字元

傳遞至規則或切面實作函式的內容物件。這個程式庫可存取分析目前目標所需的資訊和方法。

特別是，它可讓實作函式存取目前目標的標籤、屬性、設定和其依附元件的提供者。其中包含宣告輸出檔案的方法和產生這些檔案的動作。

情境物件在呼叫實作函式的期間基本上有效。在關聯函式以外的地方存取這些物件並不實用。詳情請參閱規則頁面。

成員

作業

actions ctx.actions

包含宣告輸出檔案的方法和產生這些檔案的方法。

aspect_ids

list ctx.aspect_ids

列出套用至目標的所有層面的 ID 清單。僅適用於切面實作函式。

attr

struct ctx.attr

用來存取屬性值的結構體。屬性值是由使用者提供 (如果不是，則會採用預設值)。結構的屬性和值類型會對應至提供給 rule 函式的 attrs 字典的鍵和值。查看使用範例。

bin_dir

root ctx.bin_dir

與 bin 目錄相對應的根目錄。

build_file_path

string ctx.build_file_path

這項規則的 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，隨時可能變更。請勿仰賴這項功能。

目前目標代表建構設定的值。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)

傳回是否要在為這項規則執行編譯動作時產生程式碼涵蓋率檢測，如果提供 target，則傳回該目標指定的規則。(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 (若未提供目標) 或目標來源是否應根據 --instrumentation_filter 和 --instrument_test_targets 配置設定進行檢測。這與設定中的 coverage_enabled 不同，後者會指出整個執行作業是否已啟用涵蓋範圍資料收集功能，但不會對特定目標進行檢測。

參數

參數 說明
target Target; or None； 預設值 = 無
指定規則的目標。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，則會傳回 Actions 供應程式，代表到目前規則為止建立的所有動作。針對所有其他規則，則傳回 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。

這是為了協助編寫規則實作輔助函式的測試，測試會接收 ctx 物件並建立動作。

default_provider

Provider ctx.default_provider

已淘汰，請改用 DefaultInfo。

disabled_features

list ctx.disabled_features

使用者針對這項規則明確停用的一組功能。

exec_groups

ExecGroupCollection ctx.exec_groups

這項規則可用的一組執行群組，按名稱建立索引。透過「ctx.exec_groups[name_of_group]」存取。

執行檔

struct ctx.executable

struct，包含標籤類型屬性中定義的可執行檔，並標示為 executable=True。struct 欄位對應的是屬性名稱。結構中的每個值均為 File 或 None。如果規則中未指定選用屬性，則對應的結構值會是 None。如果標籤類型未標示為 executable=True，則不會產生相對應的結構體欄位。查看使用範例。

expand_location

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

將 $(location //x) 替換為目標 //x 的輸出檔案路徑，展開指定字串中的所有 $(location ...) 範本。擴充功能僅適用於指向這項規則的直接依附性標籤，或是明確列於選用引數 targets 中的標籤。

$(location ...) 如果參照的目標有多項輸出內容，就會發生錯誤。在這種情況下，請使用 $(locations ...)，因為這會產生以空格分隔的輸出路徑清單。這也可以安全用於單一輸出檔案。

這個函式可用來讓使用者在 BUILD 檔案中指定指令 (例如 genrule)。在其他情況下，建議您直接操控標籤。

參數

參數 說明
input 必要
要展開的字串。
targets sequence of Targets； 預設 = []
列出其他查詢資訊的目標清單。
short_paths 預設值 = 否
使用根相對路徑，而非完整執行路徑
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。
在展開所有「Make 變數」參照後傳回字串。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.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 workspace name as defined in the WORKSPACE file.