規則或面向的實作函式所傳遞的內容物件。可存取分析目前目標所需的資訊和方法。
具體來說,這可讓實作函式存取目前目標的標籤、屬性、設定,以及其依附元件的提供者。這個類別提供方法,可宣告輸出檔案和產生這些檔案的動作。
內容物件基本上會在呼叫實作函式的期間保留。在相關聯函式以外存取這些物件並無實用性。詳情請參閱「規則」頁面。
成員
- 動作
- aspect_ids
- attr
- bin_dir
- build_file_path
- build_setting_value
- 設定
- coverage_instrumented
- created_actions
- disabled_features
- exec_groups
- 可執行
- expand_location
- expand_make_variables
- 功能
- file
- files
- 片段
- genfiles_dir
- info_file
- label
- outputs
- resolve_command
- resolve_tools
- rule
- runfiles
- split_attr
- super
- target_platform_has_constraint
- 工具鍊
- var
- version_file
- workspace_name
作業
actions ctx.actions包含宣告輸出檔案和產生這些檔案的動作的方法。
aspect_ids
list ctx.aspect_ids套用至目標的所有面向 ID 清單。僅適用於面向切入點的實作函式。
attr
struct ctx.attr用於存取屬性值的結構體。這些值由使用者提供 (如未提供,則會使用預設值)。結構體的屬性和值類型,會對應至提供給
rule
函式的 attrs
字典鍵和值。查看使用範例。
bin_dir
root ctx.bin_dir對應至 bin 目錄的根目錄。
build_file_path
string ctx.build_file_path相對於來源根目錄,此規則的 BUILD 檔案路徑。
build_setting_value
unknown ctx.build_setting_value目前目標所代表的建構設定值。如果這不是設定
build_setting
屬性的規則例項的上下文,讀取這個值會導致錯誤。設定
configuration ctx.configuration預設設定。詳情請參閱設定類型。
coverage_instrumented
bool ctx.coverage_instrumented(target=None)傳回是否應在執行此規則或 (如果提供
target
的話) 由該目標指定的規則時,產生程式碼涵蓋率檢測工具。(如果提供了非規則或 Starlark 規則目標,則會傳回 False。)檢查目前規則的來源 (如果未提供目標) 或目標來源是否應根據 --instrumentation_filter 和 --instrument_test_targets 設定進行檢測。這與設定中的 coverage_enabled
不同,後者會指出是否要為整個執行作業啟用涵蓋率資料收集,但不會指出是否要為特定目標進行檢測。
參數
參數 | 說明 |
---|---|
target
|
Target 或 None ;預設為 None 。指定規則的 Target。如未提供,則會預設為目前的規則。 |
created_actions
StarlarkValue ctx.created_actions()如果規則的 _skylark_testable 設為
True
,這項作業會傳回 Actions
供應器,代表目前規則至今為止所建立的所有動作。對於所有其他規則,則會傳回 None
。請注意,後續動作建立時不會更新供應器,因此如要檢查,您必須再次呼叫這個函式。這有助於為規則實作輔助函式編寫測試,這些函式可能會接收
ctx
物件,並在該物件上建立動作。
disabled_features
list ctx.disabled_features使用者針對這項規則明確停用的一組功能。
exec_groups
ExecGroupCollection ctx.exec_groups這個規則可用的執行群組集合,並以名稱做為索引。使用
ctx.exec_groups[name_of_group]
存取。
執行檔
struct ctx.executable
struct
包含在標籤類型屬性中定義的執行檔,並標示為 executable=True
。結構體欄位會對應至屬性名稱。結構體中的每個值都是 File
或 None
。如果規則中未指定選用屬性,則對應的結構體值為 None
。如果標籤類型未標示為 executable=True
,系統就不會產生對應的 struct 欄位。查看使用範例。expand_location
string ctx.expand_location(input, targets=[])將
$(location //x)
替換為目標 //x 的輸出檔案路徑,藉此展開指定字串中的所有 $(location ...)
範本。展開功能僅適用於指向此規則直接依附元件的標籤,或是在選用引數 targets
中明確列出的標籤。如果參照的目標有多個輸出項目,$(location ...)
就會導致錯誤。在這種情況下,請使用 $(locations ...)
,因為它會產生以空格分隔的輸出路徑清單。這項功能也能安全地用於單一輸出檔案。這項功能可讓使用者在 BUILD 檔案中指定指令 (例如
genrule
)。在其他情況下,直接操作標籤通常會是較佳做法。
參數
參數 | 說明 |
---|---|
input
|
required String to be expanded. |
targets
|
序列為「目標」;預設為 [] 目標清單可提供額外查詢資訊。 |
None
。
expand_make_variables
string ctx.expand_make_variables(attribute_name, command, additional_substitutions)已淘汰。請改用 ctx.var 存取變數。
在展開所有「Make 變數」參照後,會傳回字串。變數必須採用下列格式:
$(VAR_NAME)
。其他班次:$$VAR_NAME
expands to $VAR_NAME
. Examples:ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"}) # == "Hi" ctx.expand_make_variables("cmd", "$$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.featuresThe set of features that are explicitly enabled by the user for this rule. See example of use.
file
struct ctx.fileA
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.filesA
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.fragmentsAllows access to configuration fragments in target configuration.
genfiles_dir
root ctx.genfiles_dirThe root corresponding to genfiles directory.
info_file
File ctx.info_fileThe 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.labelThe label of the target currently being analyzed.
outputs
structure ctx.outputsA 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 correspondingFile
. - 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 correspondingFile
; otherwise the field value isNone
. - 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 ofFile
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
ortest
, 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 theexecutable
arg ofDefaultInfo
.
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 is '' Command to resolve. |
attribute
|
string; or None ;
default is None Name of the associated attribute for which to issue an error, or None. |
expand_locations
|
default is False Shall we expand $(location) variables? See ctx.expand_location() for more details. |
make_variables
|
dict; or None ;
default is None Make variables to expand, or None. |
tools
|
sequence of Targets;
default is [] List of tools (list of targets). |
label_dict
|
default is {} Dictionary of resolved labels and the corresponding list of Files (a dict of Label : list of Files). |
execution_requirements
|
default is {} 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 Targets;
default is [] List of tools (list of targets). |
rule
rule_attributes ctx.ruleRule 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 Files;
default is [] The list of files to be added to the runfiles. |
transitive_files
|
depset of Files; or None ;
default is 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 is 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 is 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 SymlinkEntrys;
default is {} Either a SymlinkEntry depset or the map of symlinks to be added to the runfiles. Symlinks are always added under the main workspace's runfiles directory (e.g. <runfiles_root>/_main/<symlink_path> , not the directory corresponding to the current target's repository. See Runfiles symlinks in the rules guide.
|
root_symlinks
|
dict; or depset of SymlinkEntrys;
default is {} 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_attrA 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.
super
unknown ctx.super()Experimental: Calls parent's implementation function and returns its providers
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.toolchainsToolchains for the default exec group of this rule.
var
dict ctx.varDictionary (String to String) of configuration variables.
version_file
File ctx.version_fileThe 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_nameThe name of the workspace, which is effectively the execution root name and runfiles prefix for the main repo. If
--enable_bzlmod
is on, this is the fixed string _main
. Otherwise, this is the workspace name as defined in the WORKSPACE file.