python/pip.bzl

# Copyright 2017 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Import pip requirements into Bazel."""

load("//python/pip_install:pip_repository.bzl", "pip_repository", _package_annotation = "package_annotation")
load("//python/pip_install:repositories.bzl", "pip_install_dependencies")
load("//python/pip_install:requirements.bzl", _compile_pip_requirements = "compile_pip_requirements")
load("//python/private:bzlmod_enabled.bzl", "BZLMOD_ENABLED")
load("//python/private:full_version.bzl", "full_version")
load("//python/private:render_pkg_aliases.bzl", "NO_MATCH_ERROR_MESSAGE_TEMPLATE")

compile_pip_requirements = _compile_pip_requirements
package_annotation = _package_annotation

def pip_install(requirements = None, name = "pip", allow_pip_install = False, **kwargs):
    """Will be removed in 0.28.0

    Args:
        requirements (Label): A 'requirements.txt' pip requirements file.
        name (str, optional): A unique name for the created external repository (default 'pip').
        allow_pip_install (bool, optional): change this to keep this rule working (default False).
        **kwargs (dict): Additional arguments to the [`pip_repository`](./pip_repository.md) repository rule.
    """

    if allow_pip_install:
        pip_parse(requirements = requirements, name = name, **kwargs)
    else:
        fail("pip_install support has been disabled, please use pip_parse as a replacement.")

def pip_parse(requirements = None, requirements_lock = None, name = "pip_parsed_deps", **kwargs):
    """Accepts a locked/compiled requirements file and installs the dependencies listed within.

    Those dependencies become available in a generated `requirements.bzl` file.
    You can instead check this `requirements.bzl` file into your repo, see the "vendoring" section below.

    This macro wraps the [`pip_repository`](./pip_repository.md) rule that invokes `pip`.
    In your WORKSPACE file:

    ```python
    load("@rules_python//python:pip.bzl", "pip_parse")

    pip_parse(
        name = "pip_deps",
        requirements_lock = ":requirements.txt",
    )

    load("@pip_deps//:requirements.bzl", "install_deps")

    install_deps()
    ```

    You can then reference installed dependencies from a `BUILD` file with:

    ```python
    load("@pip_deps//:requirements.bzl", "requirement")

    py_library(
        name = "bar",
        ...
        deps = [
           "//my/other:dep",
           requirement("requests"),
           requirement("numpy"),
        ],
    )
    ```

    In addition to the `requirement` macro, which is used to access the generated `py_library`
    target generated from a package's wheel, The generated `requirements.bzl` file contains
    functionality for exposing [entry points][whl_ep] as `py_binary` targets as well.

    [whl_ep]: https://packaging.python.org/specifications/entry-points/

    ```python
    load("@pip_deps//:requirements.bzl", "entry_point")

    alias(
        name = "pip-compile",
        actual = entry_point(
            pkg = "pip-tools",
            script = "pip-compile",
        ),
    )
    ```

    Note that for packages whose name and script are the same, only the name of the package
    is needed when calling the `entry_point` macro.

    ```python
    load("@pip_deps//:requirements.bzl", "entry_point")

    alias(
        name = "flake8",
        actual = entry_point("flake8"),
    )
    ```

    ## Vendoring the requirements.bzl file

    In some cases you may not want to generate the requirements.bzl file as a repository rule
    while Bazel is fetching dependencies. For example, if you produce a reusable Bazel module
    such as a ruleset, you may want to include the requirements.bzl file rather than make your users
    install the WORKSPACE setup to generate it.
    See https://github.com/bazelbuild/rules_python/issues/608

    This is the same workflow as Gazelle, which creates `go_repository` rules with
    [`update-repos`](https://github.com/bazelbuild/bazel-gazelle#update-repos)

    To do this, use the "write to source file" pattern documented in
    https://blog.aspect.dev/bazel-can-write-to-the-source-folder
    to put a copy of the generated requirements.bzl into your project.
    Then load the requirements.bzl file directly rather than from the generated repository.
    See the example in rules_python/examples/pip_parse_vendored.

    Args:
        requirements_lock (Label): A fully resolved 'requirements.txt' pip requirement file
            containing the transitive set of your dependencies. If this file is passed instead
            of 'requirements' no resolve will take place and pip_repository will create
            individual repositories for each of your dependencies so that wheels are
            fetched/built only for the targets specified by 'build/run/test'.
            Note that if your lockfile is platform-dependent, you can use the `requirements_[platform]`
            attributes.
        requirements (Label): Deprecated. See requirements_lock.
        name (str, optional): The name of the generated repository. The generated repositories
            containing each requirement will be of the form `<name>_<requirement-name>`.
        **kwargs (dict): Additional arguments to the [`pip_repository`](./pip_repository.md) repository rule.
    """
    pip_install_dependencies()

    # Temporary compatibility shim.
    # pip_install was previously document to use requirements while pip_parse was using requirements_lock.
    # We would prefer everyone move to using requirements_lock, but we maintain a temporary shim.
    reqs_to_use = requirements_lock if requirements_lock else requirements

    pip_repository(
        name = name,
        requirements_lock = reqs_to_use,
        **kwargs
    )

def _multi_pip_parse_impl(rctx):
    rules_python = rctx.attr._rules_python_workspace.workspace_name
    load_statements = []
    install_deps_calls = []
    process_requirements_calls = []
    for python_version, pypi_repository in rctx.attr.pip_parses.items():
        sanitized_python_version = python_version.replace(".", "_")
        load_statement = """\
load(
    "@{pypi_repository}//:requirements.bzl",
    _{sanitized_python_version}_install_deps = "install_deps",
    _{sanitized_python_version}_all_requirements = "all_requirements",
)""".format(
            pypi_repository = pypi_repository,
            sanitized_python_version = sanitized_python_version,
        )
        load_statements.append(load_statement)
        process_requirements_call = """\
_process_requirements(
    pkg_labels = _{sanitized_python_version}_all_requirements,
    python_version = "{python_version}",
    repo_prefix = "{pypi_repository}_",
)""".format(
            pypi_repository = pypi_repository,
            python_version = python_version,
            sanitized_python_version = sanitized_python_version,
        )
        process_requirements_calls.append(process_requirements_call)
        install_deps_call = """    _{sanitized_python_version}_install_deps(**whl_library_kwargs)""".format(
            sanitized_python_version = sanitized_python_version,
        )
        install_deps_calls.append(install_deps_call)

    requirements_bzl = """\
# Generated by python/pip.bzl

load("@{rules_python}//python:pip.bzl", "whl_library_alias")
{load_statements}

_wheel_names = []
_version_map = dict()
def _process_requirements(pkg_labels, python_version, repo_prefix):
    for pkg_label in pkg_labels:
        workspace_name = Label(pkg_label).workspace_name
        wheel_name = workspace_name[len(repo_prefix):]
        _wheel_names.append(wheel_name)
        if not wheel_name in _version_map:
            _version_map[wheel_name] = dict()
        _version_map[wheel_name][python_version] = repo_prefix

{process_requirements_calls}

def _clean_name(name):
    return name.replace("-", "_").replace(".", "_").lower()

def requirement(name):
    return "@{name}_" + _clean_name(name) + "//:pkg"

def whl_requirement(name):
    return "@{name}_" + _clean_name(name) + "//:whl"

def data_requirement(name):
    return "@{name}_" + _clean_name(name) + "//:data"

def dist_info_requirement(name):
    return "@{name}_" + _clean_name(name) + "//:dist_info"

def entry_point(pkg, script = None):
    fail("Not implemented yet")

def install_deps(**whl_library_kwargs):
{install_deps_calls}
    for wheel_name in _wheel_names:
        whl_library_alias(
            name = "{name}_" + wheel_name,
            wheel_name = wheel_name,
            default_version = "{default_version}",
            version_map = _version_map[wheel_name],
        )
""".format(
        name = rctx.attr.name,
        install_deps_calls = "\n".join(install_deps_calls),
        load_statements = "\n".join(load_statements),
        process_requirements_calls = "\n".join(process_requirements_calls),
        rules_python = rules_python,
        default_version = rctx.attr.default_version,
    )
    rctx.file("requirements.bzl", requirements_bzl)
    rctx.file("BUILD.bazel", "exports_files(['requirements.bzl'])")

_multi_pip_parse = repository_rule(
    _multi_pip_parse_impl,
    attrs = {
        "default_version": attr.string(),
        "pip_parses": attr.string_dict(),
        "_rules_python_workspace": attr.label(default = Label("//:WORKSPACE")),
    },
)

def _whl_library_alias_impl(rctx):
    rules_python = rctx.attr._rules_python_workspace.workspace_name
    if rctx.attr.default_version:
        default_repo_prefix = rctx.attr.version_map[rctx.attr.default_version]
    else:
        default_repo_prefix = None
    version_map = rctx.attr.version_map.items()
    build_content = ["# Generated by python/pip.bzl"]
    for alias_name in ["pkg", "whl", "data", "dist_info"]:
        build_content.append(_whl_library_render_alias_target(
            alias_name = alias_name,
            default_repo_prefix = default_repo_prefix,
            rules_python = rules_python,
            version_map = version_map,
            wheel_name = rctx.attr.wheel_name,
        ))
    rctx.file("BUILD.bazel", "\n".join(build_content))

def _whl_library_render_alias_target(
        alias_name,
        default_repo_prefix,
        rules_python,
        version_map,
        wheel_name):
    # The template below adds one @, but under bzlmod, the name
    # is canonical, so we have to add a second @.
    if BZLMOD_ENABLED:
        rules_python = "@" + rules_python

    alias = ["""\
alias(
    name = "{alias_name}",
    actual = select({{""".format(alias_name = alias_name)]
    for [python_version, repo_prefix] in version_map:
        alias.append("""\
        "@{rules_python}//python/config_settings:is_python_{full_python_version}": "{actual}",""".format(
            full_python_version = full_version(python_version),
            actual = "@{repo_prefix}{wheel_name}//:{alias_name}".format(
                repo_prefix = repo_prefix,
                wheel_name = wheel_name,
                alias_name = alias_name,
            ),
            rules_python = rules_python,
        ))
    if default_repo_prefix:
        default_actual = "@{repo_prefix}{wheel_name}//:{alias_name}".format(
            repo_prefix = default_repo_prefix,
            wheel_name = wheel_name,
            alias_name = alias_name,
        )
        alias.append('        "//conditions:default": "{default_actual}",'.format(
            default_actual = default_actual,
        ))

    alias.append("    },")  # Close select expression condition dict
    if not default_repo_prefix:
        supported_versions = sorted([python_version for python_version, _ in version_map])
        alias.append('    no_match_error="""{}""",'.format(
            NO_MATCH_ERROR_MESSAGE_TEMPLATE.format(
                supported_versions = ", ".join(supported_versions),
                rules_python = rules_python,
            ),
        ))
    alias.append("    ),")  # Close the select expression
    alias.append('    visibility = ["//visibility:public"],')
    alias.append(")")  # Close the alias() expression
    return "\n".join(alias)

whl_library_alias = repository_rule(
    _whl_library_alias_impl,
    attrs = {
        "default_version": attr.string(
            mandatory = False,
            doc = "Optional Python version in major.minor format, e.g. '3.10'." +
                  "The Python version of the wheel to use when the versions " +
                  "from `version_map` don't match. This allows the default " +
                  "(version unaware) rules to match and select a wheel. If " +
                  "not specified, then the default rules won't be able to " +
                  "resolve a wheel and an error will occur.",
        ),
        "version_map": attr.string_dict(mandatory = True),
        "wheel_name": attr.string(mandatory = True),
        "_rules_python_workspace": attr.label(default = Label("//:WORKSPACE")),
    },
)

def multi_pip_parse(name, default_version, python_versions, python_interpreter_target, requirements_lock, **kwargs):
    """NOT INTENDED FOR DIRECT USE!

    This is intended to be used by the multi_pip_parse implementation in the template of the
    multi_toolchain_aliases repository rule.

    Args:
        name: the name of the multi_pip_parse repository.
        default_version: the default Python version.
        python_versions: all Python toolchain versions currently registered.
        python_interpreter_target: a dictionary which keys are Python versions and values are resolved host interpreters.
        requirements_lock: a dictionary which keys are Python versions and values are locked requirements files.
        **kwargs: extra arguments passed to all wrapped pip_parse.

    Returns:
        The internal implementation of multi_pip_parse repository rule.
    """
    pip_parses = {}
    for python_version in python_versions:
        if not python_version in python_interpreter_target:
            fail("Missing python_interpreter_target for Python version %s in '%s'" % (python_version, name))
        if not python_version in requirements_lock:
            fail("Missing requirements_lock for Python version %s in '%s'" % (python_version, name))

        pip_parse_name = name + "_" + python_version.replace(".", "_")
        pip_parse(
            name = pip_parse_name,
            python_interpreter_target = python_interpreter_target[python_version],
            requirements_lock = requirements_lock[python_version],
            **kwargs
        )
        pip_parses[python_version] = pip_parse_name

    return _multi_pip_parse(
        name = name,
        default_version = default_version,
        pip_parses = pip_parses,
    )