ctx

报告问题 查看源代码

传递到规则或宽高比的实现函数的上下文对象。让您可以访问分析当前目标所需的信息和方法。

具体来说，它允许实现函数访问当前目标的标签、属性、配置及其依赖项的提供方。它包含用于声明输出文件的方法以及生成这些文件的操作。

上下文对象实质上在调用实现函数的持续时间内存在。在关联函数之外访问这些对象没有用。如需了解详情，请参阅“规则”页面。

会员

操作

actions ctx.actions

包含声明输出文件的方法以及生成输出的操作。

宽高比

list ctx.aspect_ids

应用于目标的所有方面的 ID 列表。仅适用于宽高比实现函数。

属性

struct ctx.attr

访问特性值的结构体。这些值由用户提供（如果不是，则使用默认值）。结构体的属性及其类型与提供给 rule 函数的 attrs dict 的键和值相对应。查看使用示例。

bin_dir

root ctx.bin_dir

与 bin 目录对应的根目录。

build_file_path

string ctx.build_file_path

此规则的 BUILD 文件的路径（相对于来源根目录）。

build_setting_value

unknown ctx.build_setting_value

实验性功能。此字段目前处于实验阶段，随时可能会发生变化。请勿依赖它。

由当前目标表示的构建设置的值。对于未在规则定义中设置 build_setting 属性的规则，访问此字段是错误的。

配置

configuration ctx.configuration

默认配置。如需了解详情，请参阅配置类型。

覆盖率测试

bool ctx.coverage_instrumented(target=None)

返回在执行此规则的编译操作时是否应生成代码覆盖率插桩，或者，如果提供了 target，则返回该目标指定的规则。（如果提供非规则或 Starlark 规则目标，将返回 False。）检查当前规则的来源（如果未提供目标）或目标来源应根据 --instrument_filter 和 --instrument_test_targets 配置设置进行插桩。这与配置中的 coverage_enabled 不同，后者用于说明是否针对整个运行作业启用了覆盖率数据收集，而不是用于指明特定目标是否应进行插桩。

参数

参数 说明
target Target; or None; default = None
指定规则的目标。如果未提供，则默认为当前规则。

已创建操作

StarlarkValue ctx.created_actions()

对于 _skylark_testable 设置为 True 的规则，这将返回 Actions 提供程序，该提供程序表示当前为当前规则创建的所有操作。对于所有其他规则，则返回 None。请注意，在创建后续操作时，提供程序不会更新，因此如果您要检查这些操作，必须再次调用此函数。

此变更旨在帮助为用于实现规则的辅助函数编写测试，这些函数可能会接受 ctx 对象并对其执行操作。

默认提供程序

Provider ctx.default_provider

已弃用。请改用 DefaultInfo。

已停用的功能

list ctx.disabled_features

用户在此规则中明确停用的一组功能。

高管群组

ExecGroupCollection ctx.exec_groups

可用于此规则的执行组的集合，按名称命名。使用 ctx.exec_groups[name_of_group] 进行访问。

可执行文件

struct ctx.executable

一个 struct ，其中包含在 标签类型属性中定义的标记为 executable=True 的可执行文件。结构体字段与属性名称相对应。结构体中的每个值都是 File 或 None。如果规则中未指定可选属性，则相应的结构体值为 None。如果某个标签类型未标记为 executable=True，则不会生成相应的结构体字段。查看使用示例。

展开位置

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

通过将 $(location //x) 替换为目标 //x 的输出文件的路径，展开给定字符串中的所有 $(location ...) 模板。扩展功能仅适用于指向此规则的直接依赖项标签或在可选参数 targets 中明确列出的标签。

如果引用的目标有多个输出，$(location ...) 会引发错误。在这种情况下，请使用 $(locations ...)，因为它会生成以空格分隔的输出路径列表。它也可以安全地用于单个输出文件。

借助该函数，用户可以在 BUILD 文件中指定命令（例如，对于 genrule）。在其他情况下，最好直接操作标签。

参数

参数 说明
input 必需
要展开的字符串。
targets sequence of Targets; default = []
有关其他查询信息的目标列表。
可能会返回 None。

展开变量

string ctx.expand_make_variables(attribute_name, command, additional_substitutions)

已弃用。改用 ctx.var 访问变量。
在扩展对“Make 变量”的所有引用后，返回一个字符串。变量必须采用以下格式：$(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.


        
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 Targets;
                                     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 Targets;
                                     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 Files;
                                     default = []

                          The list of files to be added to the runfiles.
            		
          

                  

            
              transitive_files
            
            
                          depset of Files; 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.
            

          

                  

            
            
                          dict; or depset of SymlinkEntrys;
                                     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.
            		
          

                  

            
            
                          dict; or depset of SymlinkEntrys;
                                     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.