Bazel pip rules

Overview

This repository provides support for installing pip packages. Usage is similar to rules_python.

Main features

• Fetch pip packages incrementally. Fetch happens only if needed by a target.

• Support for namespace packages

• Reproducible wheel builds.

• Support for passing arguments to pip_install. You can optionally pass the same arguments that pip install accepts to pip_install. For example, if you have wheels for all the packages you can have pip_install(["--only-binary", ":all"]).

• Support for python version. The assumption is that each python version has its own requirements file and the python binary of that version exists in the global environment.

requirements file

For full hermetic builds always use a requirements files that is produced by pip-compile. Also pre-build the wheels in advance. You can run pip-compile as:

$ pip-compile --allow-unsafe requirements.in

--allow-unsafe is important. For example some packages need setuptools and we need it to be in requirements file.

Otherwise, you can set compile=True in pip_import rule and the rule will try to compile the requirements file. But this process is fragile.

Setup

Add the following to your WORKSPACE file:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "com_github_ali5h_rules_pip",
    strip_prefix = "rules_pip-<revision>",
    sha256 = "<revision_hash>",
    urls = ["https://github.com/ali5h/rules_pip/archive/<revision>.tar.gz"],
)

load("@com_github_ali5h_rules_pip//:defs.bzl", "pip_import")

pip_import(
   name = "pip_deps",
   requirements = "//path/to:requirements.txt",

   # default value is "python"
   # python_interpreter="python3",

   # or specify a python runtime label
   # python_runtime="@python3_x86_64//:bin/python3",

   # set compile to true only if requirements files is not already compiled
   # compile = True
)

load("@pip_deps//:requirements.bzl", "pip_install")
pip_install([<optional pip install args])

Target dependencies

To use pip packages you can

• add dependencies via requirement macro as

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

py_binary(
    name = "main",
    srcs = ["main.py"],
    deps = [
        requirement("pip-module")
    ]
)

• use package aliases as

py_binary(
    name = "main",
    srcs = ["main.py"],
    deps = [
        "@pip_deps//:pip-module"
    ]
)