字元

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，實作函式可藉此存取目前目標的標籤、屬性、設定，以及依附元件的供應商。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。僅適用於切面實作函式。

attr

struct ctx.attr

用來存取屬性值的 struct。這些值由使用者提供 (如未提供，則會使用預設值)。struct 的屬性和值的類型，對應於提供給 rule 函式的 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

實驗功能。這個欄位仍在實驗階段，因此隨時可能變更，因此請勿依賴這項功能。

目前目標代表的建構設定值。如果規則未在規則定義中設定 build_setting 屬性，存取這個欄位就會發生錯誤。

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)

傳回為這項規則執行編譯動作時，是否應產生程式碼涵蓋率檢測程式碼；如果提供 target，則傳回該 Target 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階段啟用涵蓋率資料收集功能，但不會記錄是否應為特定目標插入檢測程式碼。

參數

參數 說明
target Target; or None; default = None
A Target specifying a rule. 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，系統不會更新供應商，因此如要檢查供應商，請再次呼叫這個函式。

這項功能旨在協助編寫規則實作輔助函式的測試，這類函式可能會接收 ctx 物件，並對該物件建立動作。

default_provider

Provider ctx.default_provider

已淘汰，請改用 DefaultInfo。

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

這個規則的可用執行群組集合 (以名稱編列索引)。使用 ctx.exec_groups[name_of_group] 存取。

執行檔

struct ctx.executable

包含以 executable=True標示的標籤類型屬性中定義的可執行檔。structStruct 欄位對應至屬性名稱。Struct 中的每個值都是 File 或 None。如果規則中未指定選填屬性，對應的 struct 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=[], short_paths=False)

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
要擴充的字串。
targets sequence of Targets; default = []
List of targets for additional lookup information.
short_paths default = False
Use root relative paths instead of full exec paths
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，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.


        
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 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 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.