BazelCon 2022 16-17 নভেম্বর নিউ ইয়র্ক এবং অনলাইনে আসছে। নিবন্ধন আজ!
নতুন: 15 নভেম্বর সম্প্রদায় দিবসের জন্য আমাদের সাথে যোগ দিন! বিস্তারিত এবং নিবন্ধন.

ctx

সেভ করা পৃষ্ঠা গুছিয়ে রাখতে 'সংগ্রহ' ব্যবহার করুন আপনার পছন্দ অনুযায়ী কন্টেন্ট সেভ করুন ও সঠিক বিভাগে রাখুন।
একটি প্রসঙ্গ বস্তু যা একটি নিয়ম বা দৃষ্টিভঙ্গির জন্য বাস্তবায়ন ফাংশনে পাস করা হয়। এটি বর্তমান লক্ষ্য বিশ্লেষণের জন্য প্রয়োজনীয় তথ্য এবং পদ্ধতিগুলিতে অ্যাক্সেস সরবরাহ করে।

বিশেষ করে, এটি বাস্তবায়ন ফাংশনকে বর্তমান লক্ষ্যের লেবেল, বৈশিষ্ট্য, কনফিগারেশন এবং এর নির্ভরতা প্রদানকারীদের অ্যাক্সেস করতে দেয়। এটিতে আউটপুট ফাইলগুলি ঘোষণা করার পদ্ধতি এবং সেগুলি তৈরি করা ক্রিয়া রয়েছে।

প্রসঙ্গ বস্তুগুলি মূলত বাস্তবায়ন ফাংশনে কলের সময়কালের জন্য বেঁচে থাকে। এই বস্তুগুলিকে তাদের সম্পর্কিত ফাংশনের বাইরে অ্যাক্সেস করা দরকারী নয়। আরও তথ্যের জন্য নিয়ম পৃষ্ঠা দেখুন।

সদস্যরা

কর্ম

actions ctx.actions

আউটপুট ফাইল ঘোষণা করার পদ্ধতি এবং সেগুলি তৈরি করে এমন ক্রিয়া রয়েছে।

aspect_ids

list ctx.aspect_ids

লক্ষ্যে প্রয়োগ করা সমস্ত দিকগুলির জন্য আইডিগুলির একটি তালিকা৷ শুধুমাত্র দৃষ্টিভঙ্গি বাস্তবায়ন ফাংশন উপলব্ধ.

attr

struct ctx.attr

বৈশিষ্ট্যের মানগুলি অ্যাক্সেস করার জন্য একটি কাঠামো। মান ব্যবহারকারী দ্বারা প্রদান করা হয় (যদি না, একটি ডিফল্ট মান ব্যবহার করা হয়)। কাঠামোর বৈশিষ্ট্য এবং তাদের মানগুলির প্রকারগুলি rule ফাংশনে দেওয়া attrs dict- এর কী এবং মানগুলির সাথে মিলে যায়। ব্যবহারের উদাহরণ দেখুন

বিন_দির

root ctx.bin_dir

বিন ডিরেক্টরির সাথে সম্পর্কিত রুট।

build_file_path

string ctx.build_file_path

এই নিয়মের জন্য BUILD ফাইলের পথ, উৎস রুটের সাথে সম্পর্কিত।

বিল্ড_সেটিং_মান

unknown ctx.build_setting_value

পরীক্ষামূলক। এই ক্ষেত্রটি পরীক্ষামূলক এবং যেকোনো সময় পরিবর্তন হতে পারে। এর উপর নির্ভর করবেন না।

বিল্ড সেটিং এর মান যা বর্তমান টার্গেট দ্বারা উপস্থাপিত হয়। নিয়মের build_setting অ্যাট্রিবিউট সেট করে না এমন নিয়মগুলির জন্য এই ক্ষেত্রটি অ্যাক্সেস করা একটি ত্রুটি।

কনফিগারেশন

configuration ctx.configuration

ডিফল্ট কনফিগারেশন। আরো বিস্তারিত জানার জন্য কনফিগারেশন প্রকার দেখুন.

coverage_instrumented

bool ctx.coverage_instrumented(target=None)

এই নিয়মের জন্য সংকলন ক্রিয়া সম্পাদন করার সময় কোড কভারেজ ইন্সট্রুমেন্টেশন তৈরি করা উচিত কিনা বা, যদি target দেওয়া হয়, সেই টার্গেট দ্বারা নির্দিষ্ট করা নিয়মটি প্রদান করে। (যদি একটি নন-রুল বা একটি স্টারলার্ক নিয়ম টার্গেট প্রদান করা হয়, তাহলে এটি ফলস প্রদান করে।) বর্তমান নিয়মের উৎসগুলি (যদি কোন লক্ষ্য প্রদান করা না হয়) বা লক্ষ্যের উত্সগুলি --ইনস্ট্রুমেন্টেশন_ফিল্টার এবং - এর উপর ভিত্তি করে ইনস্ট্রুমেন্ট করা উচিত কিনা তা পরীক্ষা করে। -instrument_test_targets কনফিগারেশন সেটিংস। এটি কনফিগারেশনে coverage_enabled থেকে আলাদা, যা পুরো রানের জন্য কভারেজ ডেটা সংগ্রহ সক্ষম কিনা তা নোট করে, কিন্তু একটি নির্দিষ্ট লক্ষ্যকে যন্ত্র করা উচিত কিনা তা নয়।

পরামিতি

প্যারামিটার বর্ণনা
target Target ; or None ; ডিফল্ট = কোনোটিই নয়
একটি নিয়ম নির্দিষ্ট করে একটি লক্ষ্য। প্রদান করা না হলে, বর্তমান নিয়মে ডিফল্ট।

তৈরি_ক্রিয়া

StarlarkValue ctx.created_actions()

_skylark_testable- এর নিয়মগুলির জন্য True তে সেট করা হয়েছে, এটি একটি অ্যাকশন প্রদানকারী প্রদান করে যা বর্তমান নিয়মের জন্য এখন পর্যন্ত তৈরি করা সমস্ত কর্মের প্রতিনিধিত্ব করে। অন্যান্য সমস্ত নিয়মের জন্য, None ফেরত দেয় না। নোট করুন যে পরবর্তী ক্রিয়াগুলি তৈরি করার সময় প্রদানকারী আপডেট করা হয় না, তাই আপনি যদি সেগুলি পরিদর্শন করতে চান তবে আপনাকে এই ফাংশনটিকে আবার কল করতে হবে৷

এটি নিয়ম-বাস্তবায়ন সহায়ক ফাংশনগুলির জন্য পরীক্ষা লিখতে সাহায্য করার উদ্দেশ্যে, যা একটি ctx অবজেক্ট গ্রহণ করতে পারে এবং এটিতে ক্রিয়া তৈরি করতে পারে।

default_provider

Provider ctx.default_provider

অবচয়। পরিবর্তে DefaultInfo ব্যবহার করুন।

disabled_features

list ctx.disabled_features

এই নিয়মের জন্য ব্যবহারকারীর দ্বারা স্পষ্টভাবে অক্ষম করা বৈশিষ্ট্যগুলির সেট৷

exec_groups

ExecGroupCollection ctx.exec_groups

এই নিয়মের জন্য উপলব্ধ মৃত্যুদন্ড গোষ্ঠীর একটি সংগ্রহ, তাদের নামের দ্বারা সূচিত করা হয়েছে। ctx.exec_groups[name_of_group] দিয়ে অ্যাক্সেস করুন।

নির্বাহযোগ্য

struct ctx.executable

executable=True হিসেবে চিহ্নিত লেবেল টাইপ অ্যাট্রিবিউটে সংজ্ঞায়িত এক্সিকিউটেবল ফাইল সমন্বিত একটি struct । struct ক্ষেত্রগুলি অ্যাট্রিবিউট নামের সাথে মিলে যায়। স্ট্রাকটের প্রতিটি মান হয় একটি File বা None । যদি একটি ঐচ্ছিক বৈশিষ্ট্য নিয়মে নির্দিষ্ট করা না থাকে তাহলে সংশ্লিষ্ট struct মানটি None হয়। যদি একটি লেবেল executable=True হিসেবে চিহ্নিত না করা হয়, তাহলে কোনো সংশ্লিষ্ট struct ক্ষেত্র তৈরি হয় না। ব্যবহারের উদাহরণ দেখুন

প্রসারিত_অবস্থান

string ctx.expand_location(input, targets=[], short_paths=False)

টার্গেট //x-এর আউটপুট ফাইলের পাথ দিয়ে $(location //x) প্রতিস্থাপন করে প্রদত্ত স্ট্রিং-এর সমস্ত $(location ...) টেমপ্লেট প্রসারিত করে। সম্প্রসারণ শুধুমাত্র সেই লেবেলগুলির জন্য কাজ করে যা এই নিয়মের সরাসরি নির্ভরতা নির্দেশ করে বা যেগুলি ঐচ্ছিক আর্গুমেন্ট targets স্পষ্টভাবে তালিকাভুক্ত।

উল্লেখিত লক্ষ্যে একাধিক আউটপুট থাকলে $(location ...) একটি ত্রুটি সৃষ্টি করবে। এই ক্ষেত্রে, অনুগ্রহ করে $(locations ...) ব্যবহার করুন যেহেতু এটি আউটপুট পাথগুলির একটি স্থান-বিচ্ছিন্ন তালিকা তৈরি করে। এটি নিরাপদে একটি একক আউটপুট ফাইলের জন্যও ব্যবহার করা যেতে পারে।

এই ফাংশনটি ব্যবহারকারীকে একটি BUILD ফাইলে (যেমন genrule জন্য) একটি কমান্ড নির্দিষ্ট করতে দেওয়ার জন্য দরকারী। অন্যান্য ক্ষেত্রে, লেবেলগুলি সরাসরি ম্যানিপুলেট করা প্রায়শই ভাল।

পরামিতি

প্যারামিটার বর্ণনা
input প্রয়োজনীয়
স্ট্রিং প্রসারিত করা হবে.
targets sequence of Target s ; ডিফল্ট = []
অতিরিক্ত অনুসন্ধান তথ্যের জন্য লক্ষ্যগুলির তালিকা।
short_paths ডিফল্ট = মিথ্যা
সম্পূর্ণ exec পাথের পরিবর্তে রুট আপেক্ষিক পাথ ব্যবহার করুন
None ফেরত দিতে পারে না।

expand_make_variables

string ctx.expand_make_variables(attribute_name, command, additional_substitutions)

অবচয়। পরিবর্তে ভেরিয়েবল অ্যাক্সেস করতে ctx.var ব্যবহার করুন।
"ভেরিয়েবল তৈরি করুন" এর সমস্ত রেফারেন্স প্রসারিত করার পরে একটি স্ট্রিং প্রদান করে। ভেরিয়েবলের অবশ্যই নিম্নলিখিত বিন্যাস থাকতে হবে: $(VAR_NAME) । এছাড়াও, $$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.
$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.
$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.
$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.
$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.
$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.
$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.
$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.
$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features l10n-placeholder17 The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file l10n-placeholder18 A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files l10n-placeholder20 A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments l10n-placeholder22 Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir l10n-placeholder23 The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration l10n-placeholder24 The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments l10n-placeholder25 Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file l10n-placeholder26 The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label l10n-placeholder27 The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:

ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file l10n-placeholder28 DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.

$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
The attribute name. Used for error reporting. command required
The expression to expand. It can contain references to "Make variables". additional_substitutions required
Additional substitutions to make beyond the default make variables. features
list ctx.features
The set of features that are explicitly enabled by the user for this rule. See example of use . file
struct ctx.file
A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
list(ctx.attr.<ATTR>.files)[0]
In other words, use file to access the (singular) default output of a dependency. See example of use . files
struct ctx.files
A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
[f for t in ctx.attr.<ATTR> for f in t.files]
In other words, use files to access the default outputs of a dependency. See example of use . fragments
fragments ctx.fragments
Allows access to configuration fragments in target configuration. genfiles_dir
root ctx.genfiles_dir
The root corresponding to genfiles directory. host_configuration
configuration ctx.host_configuration
The host configuration. See the configuration type for more details. host_fragments
fragments ctx.host_fragments
Allows access to configuration fragments in host configuration. info_file
File ctx.info_file
The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
Label ctx.label
The label of the target currently being analyzed. new_file
File ctx.new_file(var1, var2=unbound, var3=unbound)
DEPRECATED. Use ctx.actions.declare_file .
Creates a file object. There are four possible signatures to this method:
new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
var2 string ; or File ; default = unbound
var3 string ; default = unbound
outputs
structure ctx.outputs
A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
(Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
Command to resolve. attribute string ; or None ; default = None
Name of the associated attribute for which to issue an error, or None. expand_locations default = False
Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
Make variables to expand, or None. tools sequence of Target s ; default = []
List of tools (list of targets). label_dict default = {}
Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
tuple ctx.resolve_tools(tools=[])
Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
List of tools (list of targets). rule
rule_attributes ctx.rule
Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
struct ctx.split_attr
A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
bool ctx.target_platform_has_constraint(constraintValue)
Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
The constraint value to check the target platform against. toolchains
ToolchainContext ctx.toolchains
Toolchains for the default exec group of this rule. var
dict ctx.var
Dictionary (String to String) of configuration variables. version_file
File ctx.version_file
The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
string ctx.workspace_name
The workspace name as defined in the WORKSPACE file.
  • $$VAR_NAME expands to $VAR_NAME. Examples:
    ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
    ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
    The attribute name. Used for error reporting. command required
    The expression to expand. It can contain references to "Make variables". additional_substitutions required
    Additional substitutions to make beyond the default make variables. features
    list ctx.features
    The set of features that are explicitly enabled by the user for this rule. See example of use . file
    struct ctx.file
    A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
    list(ctx.attr.<ATTR>.files)[0]
    In other words, use file to access the (singular) default output of a dependency. See example of use . files
    struct ctx.files
    A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
    [f for t in ctx.attr.<ATTR> for f in t.files]
    In other words, use files to access the default outputs of a dependency. See example of use . fragments
    fragments ctx.fragments
    Allows access to configuration fragments in target configuration. genfiles_dir
    root ctx.genfiles_dir
    The root corresponding to genfiles directory. host_configuration
    configuration ctx.host_configuration
    The host configuration. See the configuration type for more details. host_fragments
    fragments ctx.host_fragments
    Allows access to configuration fragments in host configuration. info_file
    File ctx.info_file
    The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
    Label ctx.label
    The label of the target currently being analyzed. new_file
    File ctx.new_file(var1, var2=unbound, var3=unbound)
    DEPRECATED. Use ctx.actions.declare_file .
    Creates a file object. There are four possible signatures to this method:
    new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
    Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
    var2 string ; or File ; default = unbound
    var3 string ; default = unbound
    outputs
    structure ctx.outputs
    A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
    tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
    (Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
    Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
    Command to resolve. attribute string ; or None ; default = None
    Name of the associated attribute for which to issue an error, or None. expand_locations default = False
    Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
    Make variables to expand, or None. tools sequence of Target s ; default = []
    List of tools (list of targets). label_dict default = {}
    Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
    Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
    tuple ctx.resolve_tools(tools=[])
    Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

    In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
    List of tools (list of targets). rule
    rule_attributes ctx.rule
    Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
    runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
    Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
    The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
    The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
    Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
    Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
    Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
    Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
    struct ctx.split_attr
    A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
    bool ctx.target_platform_has_constraint(constraintValue)
    Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
    The constraint value to check the target platform against. toolchains
    ToolchainContext ctx.toolchains
    Toolchains for the default exec group of this rule. var
    dict ctx.var
    Dictionary (String to String) of configuration variables. version_file
    File ctx.version_file
    The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
    string ctx.workspace_name
    The workspace name as defined in the WORKSPACE file.
  • $$VAR_NAME expands to $VAR_NAME. Examples:
    ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
    ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
    The attribute name. Used for error reporting. command required
    The expression to expand. It can contain references to "Make variables". additional_substitutions required
    Additional substitutions to make beyond the default make variables. features
    list ctx.features
    The set of features that are explicitly enabled by the user for this rule. See example of use . file
    struct ctx.file
    A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
    list(ctx.attr.<ATTR>.files)[0]
    In other words, use file to access the (singular) default output of a dependency. See example of use . files
    struct ctx.files
    A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
    [f for t in ctx.attr.<ATTR> for f in t.files]
    In other words, use files to access the default outputs of a dependency. See example of use . fragments
    fragments ctx.fragments
    Allows access to configuration fragments in target configuration. genfiles_dir
    root ctx.genfiles_dir
    The root corresponding to genfiles directory. host_configuration
    configuration ctx.host_configuration
    The host configuration. See the configuration type for more details. host_fragments
    fragments ctx.host_fragments
    Allows access to configuration fragments in host configuration. info_file
    File ctx.info_file
    The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
    Label ctx.label
    The label of the target currently being analyzed. new_file
    File ctx.new_file(var1, var2=unbound, var3=unbound)
    DEPRECATED. Use ctx.actions.declare_file .
    Creates a file object. There are four possible signatures to this method:
    new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
    Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
    var2 string ; or File ; default = unbound
    var3 string ; default = unbound
    outputs
    structure ctx.outputs
    A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
    tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
    (Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
    Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
    Command to resolve. attribute string ; or None ; default = None
    Name of the associated attribute for which to issue an error, or None. expand_locations default = False
    Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
    Make variables to expand, or None. tools sequence of Target s ; default = []
    List of tools (list of targets). label_dict default = {}
    Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
    Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools
    tuple ctx.resolve_tools(tools=[])
    Returns a tuple (inputs, input_manifests) of the depset of resolved inputs and the runfiles metadata required to run the tools, both of them suitable for passing as the same-named arguments of the ctx.actions.run method.

    In contrast to ctx.resolve_command , this method does not require that Bash be installed on the machine, so it's suitable for rules built on Windows. Parameters Parameter Description tools sequence of Target s ; default = []
    List of tools (list of targets). rule
    rule_attributes ctx.rule
    Rule attributes descriptor for the rule that the aspect is applied to. Only available in aspect implementation functions. runfiles
    runfiles ctx.runfiles(files=[], transitive_files=None, collect_data=False, collect_default=False, symlinks={}, root_symlinks={})
    Creates a runfiles object. Parameters Parameter Description files sequence of File s ; default = []
    The list of files to be added to the runfiles. transitive_files depset of File s; or None ; default = None
    The (transitive) set of files to be added to the runfiles. The depset should use the default order (which, as the name implies, is the default). collect_data default = False
    Use of this parameter is not recommended. See runfiles guide . Whether to collect the data runfiles from the dependencies in srcs, data and deps attributes. collect_default default = False
    Use of this parameter is not recommended. See runfiles guide . Whether to collect the default runfiles from the dependencies in srcs, data and deps attributes. symlinks dict ; or depset of SymlinkEntry s ; default = {}
    Either a SymlinkEntry depset or the map of symlinks, prefixed by workspace name, to be added to the runfiles. See Runfiles symlinks in the rules guide. root_symlinks dict ; or depset of SymlinkEntry s ; default = {}
    Either a SymlinkEntry depset or a map of symlinks to be added to the runfiles. See Runfiles symlinks in the rules guide. split_attr
    struct ctx.split_attr
    A struct to access the values of attributes with split configurations. If the attribute is a label list, the value of split_attr is a dict of the keys of the split (as strings) to lists of the ConfiguredTargets in that branch of the split. If the attribute is a label, then the value of split_attr is a dict of the keys of the split (as strings) to single ConfiguredTargets. Attributes with split configurations still appear in the attr struct, but their values will be single lists with all the branches of the split merged together. target_platform_has_constraint
    bool ctx.target_platform_has_constraint(constraintValue)
    Returns true if the given constraint value is part of the current target platform. Parameters Parameter Description constraintValue required
    The constraint value to check the target platform against. toolchains
    ToolchainContext ctx.toolchains
    Toolchains for the default exec group of this rule. var
    dict ctx.var
    Dictionary (String to String) of configuration variables. version_file
    File ctx.version_file
    The file that is used to hold the volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. workspace_name
    string ctx.workspace_name
    The workspace name as defined in the WORKSPACE file.
  • $$VAR_NAME expands to $VAR_NAME. Examples:
    ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
    ctx.expand_make_variables("cmd", "$$PWD", {}) # == "$PWD" Additional variables may come from other places, such as configurations. Note that this function is experimental. Parameters Parameter Description attribute_name required
    The attribute name. Used for error reporting. command required
    The expression to expand. It can contain references to "Make variables". additional_substitutions required
    Additional substitutions to make beyond the default make variables. features
    list ctx.features
    The set of features that are explicitly enabled by the user for this rule. See example of use . file
    struct ctx.file
    A struct containing files defined in label type attributes marked as allow_single_file . The struct fields correspond to the attribute names. The struct value is always a File or None . If an optional attribute is not specified in the rule then the corresponding struct value is None . If a label type is not marked as allow_single_file , no corresponding struct field is generated. It is a shortcut for:
    list(ctx.attr.<ATTR>.files)[0]
    In other words, use file to access the (singular) default output of a dependency. See example of use . files
    struct ctx.files
    A struct containing files defined in label or label list type attributes. The struct fields correspond to the attribute names. The struct values are list of File s. It is a shortcut for:
    [f for t in ctx.attr.<ATTR> for f in t.files]
    In other words, use files to access the default outputs of a dependency. See example of use . fragments
    fragments ctx.fragments
    Allows access to configuration fragments in target configuration. genfiles_dir
    root ctx.genfiles_dir
    The root corresponding to genfiles directory. host_configuration
    configuration ctx.host_configuration
    The host configuration. See the configuration type for more details. host_fragments
    fragments ctx.host_fragments
    Allows access to configuration fragments in host configuration. info_file
    File ctx.info_file
    The file that is used to hold the non-volatile workspace status for the current build request. See documentation for --workspace_status_command for more information. label
    Label ctx.label
    The label of the target currently being analyzed. new_file
    File ctx.new_file(var1, var2=unbound, var3=unbound)
    DEPRECATED. Use ctx.actions.declare_file .
    Creates a file object. There are four possible signatures to this method:
    new_file(filename): Creates a file object with the given filename in the current package. new_file(file_root, filename): Creates a file object with the given filename under the given file root. new_file(sibling_file, filename): Creates a file object in the same directory as the given sibling file. new_file(file_root, sibling_file, suffix): Creates a file object with same base name of the sibling_file but with different given suffix, under the given file root.
    Does not actually create a file on the file system, just declares that some action will do so. You must create an action that generates the file. If the file should be visible to other rules, declare a rule output instead when possible. Doing so enables Blaze to associate a label with the file that rules can refer to (allowing finer dependency control) instead of referencing the whole rule. Parameters Parameter Description var1 string ; or root ; or File ; required
    var2 string ; or File ; default = unbound
    var3 string ; default = unbound
    outputs
    structure ctx.outputs
    A pseudo-struct containing all the predeclared output files, represented by File objects. See the Rules page for more information and examples. This field does not exist on aspect contexts, since aspects do not have predeclared outputs. The fields of this object are defined as follows. It is an error if two outputs produce the same field name or have the same label. If the rule declares an outputs dict, then for every entry in the dict, there is a field whose name is the key and whose value is the corresponding File . For every attribute of type attr.output that the rule declares, there is a field whose name is the attribute's name. If the target specified a label for that attribute, then the field value is the corresponding File ; otherwise the field value is None . For every attribute of type attr.output_list that the rule declares, there is a field whose name is the attribute's name. The field value is a list of File objects corresponding to the labels given for that attribute in the target, or an empty list if the attribute was not specified in the target. (Deprecated) If the rule is marked executable or test , there is a field named "executable" , which is the default executable. It is recommended that instead of using this, you pass another file (either predeclared or not) to the executable arg of DefaultInfo . resolve_command
    tuple ctx.resolve_command(command='', attribute=None, expand_locations=False, make_variables=None, tools=[], label_dict={}, execution_requirements={})
    (Experimental) Returns a tuple (inputs, command, input_manifests) of the list of resolved inputs, the argv list for the resolved command, and the runfiles metadata required to run the command, all of them suitable for passing as the same-named arguments of the ctx.action method.
    Note for Windows users : this method requires Bash (MSYS2). Consider using resolve_tools() instead (if that fits your needs). Parameters Parameter Description command default = ''
    Command to resolve. attribute string ; or None ; default = None
    Name of the associated attribute for which to issue an error, or None. expand_locations default = False
    Shall we expand $(location) variables? See ctx.expand_location() for more details. make_variables dict ; or None ; default = None
    Make variables to expand, or None. tools sequence of Target s ; default = []
    List of tools (list of targets). label_dict default = {}
    Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). execution_requirements default = {}
    Information for scheduling the action to resolve this command. See tags for useful keys. resolve_tools