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傳遞至規則或層面實作函式的內容物件。可存取分析目前目標所需的資訊和方法。

具體來說,這項功能可讓實作函式存取目前目標的標籤、屬性、設定,以及其依附元件的供應商。這個類別提供的方法可宣告輸出檔案,以及產生這些檔案的動作。

基本上,內容物件的生命週期與實作函式的呼叫時間相同。在相關聯函式以外存取這些物件並無用處。詳情請參閱規則頁面

成員

作業

actions ctx.actions

包含用於宣告輸出檔案的方法,以及產生這些檔案的動作。

aspect_ids

list ctx.aspect_ids

套用至目標的所有層面 ID 清單。僅適用於層面實作函式。

attr

struct ctx.attr

用來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)。結構的屬性和值的類型,對應於提供給 rule 函式attrs dict 的鍵和值。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

這個規則的 BUILD 檔案路徑 (相對於來源根目錄)。

build_setting_value

unknown ctx.build_setting_value

代表目前目標的建構設定值。如果這不是設定 build_setting 屬性的規則執行個體情境,讀取此屬性會發生錯誤。

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)

傳回是否應為這項規則執行編譯動作時產生程式碼涵蓋範圍檢測,或傳回 (如果提供 target) 該目標指定的規則。(如果提供非規則或 Starlark 規則的目標,則會傳回 False)。根據 --instrumentation_filter 和 --instrument_test_targets 設定,檢查目前規則的來源 (如果未提供目標) 或目標的來源是否應經過檢測。這與coverage_enabled設定不同,後者會記錄是否為整個執行作業啟用涵蓋範圍資料收集功能,但不會記錄是否應為特定目標進行插樁。

參數

參數 說明
target 目標;或 None; 預設為 None
指定規則的目標。如未提供,則預設為目前的規則。

created_actions

StarlarkValue ctx.created_actions()

如果規則的 _skylark_testable 設為 True,這會傳回 Actions 提供者,代表目前規則至今建立的所有動作。如果是其他規則,則會傳回 None。請注意,建立後續動作時,系統不會更新提供者,因此如要檢查這些動作,必須再次呼叫這個函式。

這項功能旨在協助您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,並對該物件建立動作。

disabled_features

list ctx.disabled_features

使用者為這項規則明確停用的功能集。

exec_groups

ExecGroupCollection ctx.exec_groups

這個規則可用的執行群組集合,依名稱建立索引。使用 ctx.exec_groups[name_of_group] 存取。

執行檔

struct ctx.executable

struct,其中包含標示為 executable=True標籤類型屬性中定義的可執行檔。結構體欄位對應屬性名稱。結構體中的每個值都是 FileNone。如果規則中未指定選填屬性,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=[])

將指定字串中的所有 $(location ...) 範本展開,並將 $(location //x) 替換為目標 //x 的輸出檔案路徑。擴展功能僅適用於指向這項規則直接依附元件的標籤,或選用引數 targets 中明確列出的標籤。如果參照的目標有多個輸出內容,

$(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。也可以安全地用於單一輸出檔案。

這項函式可讓使用者在 BUILD 檔案中指定指令 (例如 genrule),在其他情況下,直接操控標籤通常會比較好。

參數

參數 說明
input 必要
要展開的字串。
targets 目標序列; 預設為 []
額外查閱資訊的目標清單。
可能會傳回 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。
展開「建立變數」的所有參照後,系統會傳回字串。變數必須採用下列格式:$(VAR_NAME)。此外,$$VAR_NAME expands to $VAR_NAME. Examples:
ctx.expand_make_variables("cmd", "$(MY_VAR)", {"MY_VAR": "Hi"})  # == "Hi"
ctx.expand_make_variables("cmd", "$$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 Files. 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.

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.

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 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.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 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.

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.
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_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.

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.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 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.