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pigweed / third_party / github / bazelbuild / rules_python / d1596a309ac9216b1a17fc984eb1376e64aa5fcf
commitd1596a309ac9216b1a17fc984eb1376e64aa5fcf[log] [tgz]
authorJon Brandvein <brandjon@google.com>Fri Jul 26 23:14:09 2019 -0400
committerGitHub <noreply@github.com>Fri Jul 26 23:14:09 2019 -0400
tree6a03ad1eba2c01a77dee0280a82ebcb4f303376b
parentd852e8a063b83f1c75c2cf0bcba1a0f9e54e62d0 [diff]
Rename canonical workspace name to "@rules_python" (#212)

* Change official workspace name to @rules_python

This includes regenerating the par files to use the new name. Neat trick: Since
the par file regeneration depends on the previous par files, I had to bootstrap
this change by temporarily editing the WORKSPACE to include:

local_repository(
    name = "io_bazel_rules_python",
    path = ".",
)

* Add a nice error message to help with the workspace name migration

This hooks into pip_repositories(), which users are *supposed* to be calling in
their WORKSPACE files, to emit a nice fail() message alerting them that they
need to update their repo definition.

Without this change (and even with it, for users who do not call
`pip_repositories()`), users will instead see a confusing cyclic dependency
error.
7 files changed
tree: 6a03ad1eba2c01a77dee0280a82ebcb4f303376b
  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:python.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