Core Python rules

Core rules for building Python projects.

current_py_toolchain

This rule exists so that the current python toolchain can be used in the toolchains attribute of other rules, such as genrule. It allows exposing a python toolchain after toolchain resolution has happened, to a rule which expects a concrete implementation of a toolchain, rather than a toolchain_type which could be resolved to that toolchain.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required

py_import

This rule allows the use of Python packages as dependencies.

It imports the given .egg file(s), which might be checked in source files, fetched externally as with http_file, or produced as outputs of other rules.

It may be used like a py_library, in the deps of other Python rules.

This is similar to java_import.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
deps	The list of other libraries to be linked in to the binary target.	List of labels	optional	[]
srcs	The list of Python package files provided to Python targets that depend on this target. Note that currently only the .egg format is accepted. For .whl files, try the whl_library rule. We accept contributions to extend py_import to handle .whl.	List of labels	optional	[]

py_binary

See the Bazel core py_binary documentation.

PARAMETERS

Name	Description	Default Value
attrs	Rule attributes	none

py_library

See the Bazel core py_library documentation.

PARAMETERS

Name	Description	Default Value
attrs	Rule attributes	none

py_runtime

See the Bazel core py_runtime documentation.

PARAMETERS

Name	Description	Default Value
attrs	Rule attributes	none

py_runtime_pair

A toolchain rule for Python.

This used to wrap up to two Python runtimes, one for Python 2 and one for Python 3. However, Python 2 is no longer supported, so it now only wraps a single Python 3 runtime.

Usually the wrapped runtimes are declared using the py_runtime rule, but any rule returning a PyRuntimeInfo provider may be used.

This rule returns a platform_common.ToolchainInfo provider with the following schema:

platform_common.ToolchainInfo(
    py2_runtime = None,
    py3_runtime = <PyRuntimeInfo or None>,
)

Example usage:

# In your BUILD file...

load("@rules_python//python:defs.bzl", "py_runtime_pair")

py_runtime(
    name = "my_py3_runtime",
    interpreter_path = "/system/python3",
    python_version = "PY3",
)

py_runtime_pair(
    name = "my_py_runtime_pair",
    py3_runtime = ":my_py3_runtime",
)

toolchain(
    name = "my_toolchain",
    target_compatible_with = <...>,
    toolchain = ":my_py_runtime_pair",
    toolchain_type = "@rules_python//python:toolchain_type",
)

# In your WORKSPACE...

register_toolchains("//my_pkg:my_toolchain")

PARAMETERS

Name	Description	Default Value
name	str, the name of the target	none
py2_runtime	optional Label; must be unset or None; an error is raised otherwise.	None
py3_runtime	Label; a target with PyRuntimeInfo for Python 3.	None
attrs	Extra attrs passed onto the native rule	none

py_test

See the Bazel core py_test documentation.

PARAMETERS

Name	Description	Default Value
attrs	Rule attributes	none

find_requirements

The aspect definition. Can be invoked on the command line as

bazel build //pkg:my_py_binary_target --aspects=@rules_python//python:defs.bzl%find_requirements --output_groups=pyversioninfo

ASPECT ATTRIBUTES

Name	Type
deps	String

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required