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Documentation for @bazel_lib@v3.2.0 — View source
General-purpose Starlark utility functions

​
Usage example

load("@bazel_lib//lib:utils.bzl", "utils")

out_label = utils.to_label(out_file)

​
Function: utils.consistent_label_str

Generate a consistent label string for all Bazel versions. Starting in Bazel 6, the workspace name is empty for the local workspace and there’s no other way to determine it. This behavior differs from Bazel 5 where the local workspace name was fully qualified in str(label). This utility function is meant for use in rules and requires the rule context to determine the user’s workspace name (ctx.workspace_name).

​
Parameters

​
ctx
name
required
The rule context.
​
label
name
required
A Label.
Returns: String representation of the label including the repository name if the label is from an external repository. For labels in the user’s repository the label will start with @//.

​
Function: utils.default_timeout

Provide a sane default for *_test timeout attribute. The test-encyclopedia says:
Tests may return arbitrarily fast regardless of timeout. A test is not penalized for an overgenerous timeout, although a warning may be issued: you should generally set your timeout as tight as you can without incurring any flakiness.
However Bazel’s default for timeout is medium, which is dumb given this guidance. It also says:
Tests which do not explicitly specify a timeout have one implied based on the test’s size as follows
Therefore if size is specified, we should allow timeout to take its implied default. If neither is set, then we can fix Bazel’s wrong default here to avoid warnings under --test_verbose_timeout_warnings. This function can be used in a macro which wraps a testing rule.

​
Parameters

​
size
name
required
the size attribute of a test target
​
timeout
name
required
the timeout attribute of a test target
Returns: “short” if neither is set, otherwise timeout

​
Function: utils.file_exists

Check whether a file exists. Useful in macros to set defaults for a configuration file if it is present. This can only be called during the loading phase, not from a rule implementation.

​
Parameters

​
path
name
required
a label, or a string which is a path relative to this package

​
Function: utils.glob_directories

​
Parameters

​
include
name
required
​
kwargs
string_list

​
Function: utils.is_bazel_6_or_greater

Detects if the Bazel version being used is greater than or equal to 6 (including Bazel 6 pre-releases and RCs). Detecting Bazel 6 or greater is particularly useful in rules as slightly different code paths may be needed to support bzlmod which was added in Bazel 6. Unlike the undocumented native.bazel_version, which only works in WORKSPACE and repository rules, this function can be used in rules and BUILD files. An alternate approach to make the Bazel version available in BUILD files and rules would be to use the host_repo repository rule which contains the bazel_version in the exported host struct: WORKSPACE: 
load("@bazel_lib//lib:host_repo.bzl", "host_repo")
host_repo(name = "bazel_lib_host")
BUILD.bazel: 
load("@bazel_lib_host//:defs.bzl", "host")
print(host.bazel_version)
That approach, however, incurs a cost in the user’s WORKSPACE. Returns: True if the Bazel version being used is greater than or equal to 6 (including pre-releases and RCs)

​
Function: utils.is_bazel_7_or_greater

Detects if the Bazel version being used is greater than or equal to 7 (including Bazel 7 pre-releases and RCs). Unlike the undocumented native.bazel_version, which only works in WORKSPACE and repository rules, this function can be used in rules and BUILD files. An alternate approach to make the Bazel version available in BUILD files and rules would be to use the host_repo repository rule which contains the bazel_version in the exported host struct: WORKSPACE: 
load("@bazel_lib//lib:host_repo.bzl", "host_repo")
host_repo(name = "bazel_lib_host")
BUILD.bazel: 
load("@bazel_lib_host//:defs.bzl", "host")
print(host.bazel_version)
That approach, however, incurs a cost in the user’s WORKSPACE. Returns: True if the Bazel version being used is greater than or equal to 7 (including pre-releases and RCs)

​
Function: utils.is_bzlmod_enabled

Detect the value of the —enable_bzlmod flag

​
Function: utils.is_external_label

Returns True if the given Label (or stringy version of a label) represents a target outside of the workspace

​
Parameters

​
param
name
required
a string or label
Returns: a bool

​
Function: utils.maybe_http_archive

Adapts a maybe(http_archive, …) to look like an http_archive. This makes WORKSPACE dependencies easier to read and update. Typical usage looks like, 
load("//lib:utils.bzl", http_archive = "maybe_http_archive")

http_archive(
    name = "aspect_rules_js",
    sha256 = "5bb643d9e119832a383e67f946dc752b6d719d66d1df9b46d840509ceb53e1f1",
    strip_prefix = "rules_js-1.6.2",
    url = "https://github.com/aspect-build/rules_js/archive/refs/tags/v1.6.2.tar.gz",
)
instead of the classic maybe pattern of, 
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")

maybe(
    http_archive,
    name = "aspect_rules_js",
    sha256 = "5bb643d9e119832a383e67f946dc752b6d719d66d1df9b46d840509ceb53e1f1",
    strip_prefix = "rules_js-1.6.2",
    url = "https://github.com/aspect-build/rules_js/archive/refs/tags/v1.6.2.tar.gz",
)

​
Parameters

​
kwargs
string_list
all arguments to pass-forward to http_archive

​
Function: utils.path_to_workspace_root

Returns the path to the workspace root under bazel Returns: Path to the workspace root

​
Function: utils.propagate_common_binary_rule_attributes

Returns a dict of rule parameters filtered from the input dict that only contains the ones that are common to all binary rules These are listed in Bazel’s documentation: https://bazel.build/reference/be/common-definitions#common-attributes https://bazel.build/reference/be/common-definitions#common-attributes-binary

​
Parameters

​
attrs
name
required
Dict of parameters to filter
Returns: The dict of parameters, containing only common binary attributes

​
Function: utils.propagate_common_rule_attributes

Returns a dict of rule parameters filtered from the input dict that only contains the ones that are common to all rules These are listed in Bazel’s documentation: https://bazel.build/reference/be/common-definitions#common-attributes

​
Parameters

​
attrs
name
required
Dict of parameters to filter
Returns: The dict of parameters, containing only common attributes

​
Function: utils.propagate_common_test_rule_attributes

Returns a dict of rule parameters filtered from the input dict that only contains the ones that are common to all test rules These are listed in Bazel’s documentation: https://bazel.build/reference/be/common-definitions#common-attributes https://bazel.build/reference/be/common-definitions#common-attributes-tests

​
Parameters

​
attrs
name
required
Dict of parameters to filter
Returns: The dict of parameters, containing only common test attributes

​
Function: utils.propagate_well_known_tags

Returns a list of tags filtered from the input set that only contains the ones that are considered “well known” These are listed in Bazel’s documentation: https://docs.bazel.build/versions/main/test-encyclopedia.html#tag-conventions https://docs.bazel.build/versions/main/be/common-definitions.html#common-attributes

​
Parameters

​
tags
name
default:"[]"
List of tags to filter
Returns: List of tags that only contains the well known set

​
Function: utils.to_label

Converts a string to a Label. If Label is supplied, the same label is returned.

​
Parameters

​
param
name
required
a string representing a label or a Label
Returns: a Label

​
Function: default_timeout

Provide a sane default for *_test timeout attribute. The test-encyclopedia says:
Tests may return arbitrarily fast regardless of timeout. A test is not penalized for an overgenerous timeout, although a warning may be issued: you should generally set your timeout as tight as you can without incurring any flakiness.
However Bazel’s default for timeout is medium, which is dumb given this guidance. It also says:
Tests which do not explicitly specify a timeout have one implied based on the test’s size as follows
Therefore if size is specified, we should allow timeout to take its implied default. If neither is set, then we can fix Bazel’s wrong default here to avoid warnings under --test_verbose_timeout_warnings. This function can be used in a macro which wraps a testing rule.

​
Parameters

​
size
name
required
the size attribute of a test target
​
timeout
name
required
the timeout attribute of a test target
Returns: “short” if neither is set, otherwise timeout

​
Function: file_exists

Check whether a file exists. Useful in macros to set defaults for a configuration file if it is present. This can only be called during the loading phase, not from a rule implementation.

​
Parameters

​
path
name
required
a label, or a string which is a path relative to this package

​
Function: glob_directories

​
Parameters

​
include
name
required
​
kwargs
string_list

​
Function: is_bazel_6_or_greater

Detects if the Bazel version being used is greater than or equal to 6 (including Bazel 6 pre-releases and RCs). Detecting Bazel 6 or greater is particularly useful in rules as slightly different code paths may be needed to support bzlmod which was added in Bazel 6. Unlike the undocumented native.bazel_version, which only works in WORKSPACE and repository rules, this function can be used in rules and BUILD files. An alternate approach to make the Bazel version available in BUILD files and rules would be to use the host_repo repository rule which contains the bazel_version in the exported host struct: WORKSPACE: 
load("@bazel_lib//lib:host_repo.bzl", "host_repo")
host_repo(name = "bazel_lib_host")
BUILD.bazel: 
load("@bazel_lib_host//:defs.bzl", "host")
print(host.bazel_version)
That approach, however, incurs a cost in the user’s WORKSPACE. Returns: True if the Bazel version being used is greater than or equal to 6 (including pre-releases and RCs)

​
Function: is_bazel_7_or_greater

Detects if the Bazel version being used is greater than or equal to 7 (including Bazel 7 pre-releases and RCs). Unlike the undocumented native.bazel_version, which only works in WORKSPACE and repository rules, this function can be used in rules and BUILD files. An alternate approach to make the Bazel version available in BUILD files and rules would be to use the host_repo repository rule which contains the bazel_version in the exported host struct: WORKSPACE: 
load("@bazel_lib//lib:host_repo.bzl", "host_repo")
host_repo(name = "bazel_lib_host")
BUILD.bazel: 
load("@bazel_lib_host//:defs.bzl", "host")
print(host.bazel_version)
That approach, however, incurs a cost in the user’s WORKSPACE. Returns: True if the Bazel version being used is greater than or equal to 7 (including pre-releases and RCs)

​
Function: is_bzlmod_enabled

Detect the value of the —enable_bzlmod flag

​
Function: is_external_label

Returns True if the given Label (or stringy version of a label) represents a target outside of the workspace

​
Parameters

​
param
name
required
a string or label
Returns: a bool

​
Function: maybe_http_archive

Adapts a maybe(http_archive, …) to look like an http_archive. This makes WORKSPACE dependencies easier to read and update. Typical usage looks like, 
load("//lib:utils.bzl", http_archive = "maybe_http_archive")

http_archive(
    name = "aspect_rules_js",
    sha256 = "5bb643d9e119832a383e67f946dc752b6d719d66d1df9b46d840509ceb53e1f1",
    strip_prefix = "rules_js-1.6.2",
    url = "https://github.com/aspect-build/rules_js/archive/refs/tags/v1.6.2.tar.gz",
)
instead of the classic maybe pattern of, 
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")

maybe(
    http_archive,
    name = "aspect_rules_js",
    sha256 = "5bb643d9e119832a383e67f946dc752b6d719d66d1df9b46d840509ceb53e1f1",
    strip_prefix = "rules_js-1.6.2",
    url = "https://github.com/aspect-build/rules_js/archive/refs/tags/v1.6.2.tar.gz",
)

​
Parameters

​
kwargs
string_list
all arguments to pass-forward to http_archive

​
Function: path_to_workspace_root

Returns the path to the workspace root under bazel Returns: Path to the workspace root

​
Function: propagate_well_known_tags

Returns a list of tags filtered from the input set that only contains the ones that are considered “well known” These are listed in Bazel’s documentation: https://docs.bazel.build/versions/main/test-encyclopedia.html#tag-conventions https://docs.bazel.build/versions/main/be/common-definitions.html#common-attributes

​
Parameters

​
tags
name
default:"[]"
List of tags to filter
Returns: List of tags that only contains the well known set

​
Function: propagate_common_rule_attributes

Returns a dict of rule parameters filtered from the input dict that only contains the ones that are common to all rules These are listed in Bazel’s documentation: https://bazel.build/reference/be/common-definitions#common-attributes

​
Parameters

​
attrs
name
required
Dict of parameters to filter
Returns: The dict of parameters, containing only common attributes

​
Function: propagate_common_test_rule_attributes

Returns a dict of rule parameters filtered from the input dict that only contains the ones that are common to all test rules These are listed in Bazel’s documentation: https://bazel.build/reference/be/common-definitions#common-attributes https://bazel.build/reference/be/common-definitions#common-attributes-tests

​
Parameters

​
attrs
name
required
Dict of parameters to filter
Returns: The dict of parameters, containing only common test attributes

​
Function: propagate_common_binary_rule_attributes

Returns a dict of rule parameters filtered from the input dict that only contains the ones that are common to all binary rules These are listed in Bazel’s documentation: https://bazel.build/reference/be/common-definitions#common-attributes https://bazel.build/reference/be/common-definitions#common-attributes-binary

​
Parameters

​
attrs
name
required
Dict of parameters to filter
Returns: The dict of parameters, containing only common binary attributes

​
Function: to_label

Converts a string to a Label. If Label is supplied, the same label is returned.

​
Parameters

​
param
name
required
a string representing a label or a Label
Returns: a Label

​
Function: consistent_label_str

Generate a consistent label string for all Bazel versions. Starting in Bazel 6, the workspace name is empty for the local workspace and there’s no other way to determine it. This behavior differs from Bazel 5 where the local workspace name was fully qualified in str(label). This utility function is meant for use in rules and requires the rule context to determine the user’s workspace name (ctx.workspace_name).

​
Parameters

​
ctx
name
required
The rule context.
​
label
name
required
A Label.
Returns: String representation of the label including the repository name if the label is from an external repository. For labels in the user’s repository the label will start with @//.