Getting started

This doc is a simplified guide to help get started quickly. It provides a simplified introduction to having a working Python program for both bzlmod and the older way of using WORKSPACE.

It assumes you have a requirements.txt file with your PyPI dependencies.

For more details information about configuring rules_python, see:

• Configuring the runtime
• Configuring third party dependencies (pip/pypi)
• API docs

Using bzlmod

The first step to using rules_python with bzlmod is to add the dependency to your MODULE.bazel file:

# Update the version "0.0.0" to the release found here:
# https://github.com/bazelbuild/rules_python/releases.
bazel_dep(name = "rules_python", version = "0.0.0")

pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
pip.parse(
    hub_name = "pypi",
    python_version = "3.11",
    requirements_lock = "//:requirements.txt",
)
use_repo(pip, "pypi")

Using a WORKSPACE file

Using WORKSPACE is deprecated, but still supported, and a bit more involved than using Bzlmod. Here is a simplified setup to download the prebuilt runtimes.

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

# Update the snippet based on the latest release below
# https://github.com/bazelbuild/rules_python/releases

http_archive(
    name = "rules_python",
    sha256 = "ca77768989a7f311186a29747e3e95c936a41dffac779aff6b443db22290d913",
    strip_prefix = "rules_python-0.36.0",
    url = "https://github.com/bazelbuild/rules_python/releases/download/0.36.0/rules_python-0.36.0.tar.gz",
)

load("@rules_python//python:repositories.bzl", "py_repositories")

py_repositories()

load("@rules_python//python:repositories.bzl", "python_register_toolchains")

python_register_toolchains(
    name = "python_3_11",
    # Available versions are listed in @rules_python//python:versions.bzl.
    # We recommend using the same version your team is already standardized on.
    python_version = "3.11",
)

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

pip_parse(
    name = "pypi",
    python_interpreter_target = "@python_3_11_host//:python",
    requirements_lock = "//:requirements.txt",
)

“Hello World”

Once you've imported the rule set using either Bzlmod or WORKSPACE, you can then load the core rules in your BUILD files with the following:

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

py_binary(
  name = "main",
  srcs = ["main.py"],
  deps = [
      "@pypi//foo",
      "@pypi//bar",
  ]
)