Google Git
Sign in
pigweed / third_party / github / bazelbuild / rules_python / 522222ae63f30a9ecb0c6a0ed0a628b4eaca4f84
commit522222ae63f30a9ecb0c6a0ed0a628b4eaca4f84[log] [tgz]
authorJon Brandvein <brandjon@google.com>Fri Jul 26 23:35:39 2019 -0400
committerGitHub <noreply@github.com>Fri Jul 26 23:35:39 2019 -0400
tree7c73513487643102bad76a50851ac75b7a07f22c
parentd1596a309ac9216b1a17fc984eb1376e64aa5fcf [diff]
Add exports for core Python logic that's bundled with Bazel (#202)

* Introduce defs.bzl as the official home of the core Python rules

The "core" Python rules are the rules that traditionally have been bundled with
Bazel. This includes native rules like `py_binary`, and Starlark-defined rules
under `@bazel_tools` like `py_runtime_pair`. These should all live in
or around `@rules_python//python:defs.bzl`.

Currently we re-export the native rules here, with a magic tag to allow them to
survive the flag flip for `--incompatible_load_python_rules_from_bzl`. When
native rules are ported to Starlark their definitions will live here.

* Add re-exports for Starlark-defined symbols

This adds export definitions for built-in symbols like `PyInfo` and
`@bazel_tools`-defined symbols like py_runtime_pair.

* Vendor in runfiles library

This vendors in the @bazel_tools//tools/python/runfiles target as
//python/runfiles. See comment in the BUILD file for why we couldn't re-export
the bundled implementation.

* Fix README to prefer defs.bzl over python.bzl
8 files changed
tree: 7c73513487643102bad76a50851ac75b7a07f22c
  1. .bazelci/
  2. .ci/
  3. docs/
  4. examples/
  5. experimental/
  6. proposals/
  7. python/
  8. rules_python/
  9. tools/
  10. .gitignore
  11. .travis.yml
  12. AUTHORS
  13. BUILD
  14. CONTRIBUTING.md
  15. CONTRIBUTORS
  16. LICENSE
  17. README.md
  18. update_docs.sh
  19. update_tools.sh
  20. WORKSPACE
README.md

Experimental Bazel Python Rules

Status: This is ALPHA software.

Build status

Recent updates

  • 2019-07-26: The canonical name of this repo has been changed from @io_bazel_rules_python to just @rules_python, in accordance with convention. Please update your WORKSPACE file and labels that reference this repo accordingly.

Rules

Overview

This repository provides Python rules for Bazel. Currently, support for rules that are available from Bazel core are simple aliases to that bundled functionality. On top of that, this repository provides support for installing dependencies typically managed via pip.

Setup

Add the following to your WORKSPACE file to add the external repositories:

load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")

git_repository(
    name = "rules_python",
    remote = "https://github.com/bazelbuild/rules_python.git",
    # NOT VALID!  Replace this with a Git commit SHA.
    commit = "{HEAD}",
)

# Only needed for PIP support:
load("@rules_python//python:pip.bzl", "pip_repositories")

pip_repositories()

Then in your BUILD files load the python rules with:

load(
  "@rules_python//python:defs.bzl",
  "py_binary", "py_library", "py_test",
)

py_binary(
  name = "main",
  ...
)

Importing pip dependencies

These rules are designed to have developers continue using requirements.txt to express their dependencies in a Python idiomatic manner. These dependencies are imported into the Bazel dependency graph via a two-phased process in WORKSPACE:

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

# This rule translates the specified requirements.txt into
# @my_deps//:requirements.bzl, which itself exposes a pip_install method.
pip_import(
   name = "my_deps",
   requirements = "//path/to:requirements.txt",
)

# Load the pip_install symbol for my_deps, and create the dependencies'
# repositories.
load("@my_deps//:requirements.bzl", "pip_install")
pip_install()

Consuming pip dependencies

Once a set of dependencies has been imported via pip_import and pip_install we can start consuming them in our py_{binary,library,test} rules. In support of this, the generated requirements.bzl also contains a requirement method, which can be used directly in deps=[] to reference an imported py_library.

load("@my_deps//:requirements.bzl", "requirement")

py_library(
    name = "mylib",
    srcs = ["mylib.py"],
    deps = [
        ":myotherlib",
	# This takes the name as specified in requirements.txt
	requirement("importeddep"),
    ]
)

Canonical whl_library naming

It is notable that whl_library rules imported via pip_import are canonically named, following the pattern: pypi__{distribution}_{version}. Characters in these components that are illegal in Bazel label names (e.g. -, .) are replaced with _.

This canonical naming helps avoid redundant work to import the same library multiple times. It is expected that this naming will remain stable, so folks should be able to reliably depend directly on e.g. @pypi__futures_3_1_1//:pkg for dependencies, however, it is recommended that folks stick with the requirement pattern in case the need arises for us to make changes to this format in the future.

“Extras” will have a target of the extra name (in place of pkg above).

Updating docs/

All of the content (except BUILD) under docs/ is generated. To update the documentation simply run this in the root of the repository:

./update_docs.sh

Updating tools/

All of the content (except BUILD) under tools/ is generated. To update the documentation simply run this in the root of the repository:

./update_tools.sh