rules_venv

Overview

This repository implements Bazel rules for Python and is designed to be a drop-in replacement for the existing rules_python where uses of @rules_python//python:defs.bzl can be replaced with @rules_venv//python:defs.bzl.

Improvements over rules_python

While rules_python has fantastic toolchain infrastructure which this repo relies on, rules_python ultimately suffers from a few issues which this repo aims to solve:

1. Use of PYTHONPATH to construct the python environment leads to operating system limitations.

   Some details on MAX_ARG_STRLEN and ARG_MAX can be found here: https://unix.stackexchange.com/a/120842

2. Slow startup on windows systems that do not support symlinks.

   rules_python creates zipapps on systems that do not support runfiles. For large projects, this can lead to large (~500MB+) zip files being constantly compressed and uncompressed to run simple actions which is a lot more expensive than systems which support runfiles.

Setup

bzlmod

bazel_dep(name = "rules_venv", version = "{version}")

WORKSPACE.bazel

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

# See releases for urls and checksums
http_archive(
    name = "rules_venv",
    sha256 = "{sha256}",
    urls = ["https://github.com/periareon/rules_venv/releases/download/{version}/rules_venv-v{version}.tar.gz"],
)

load("@rules_venv//venv:repositories.bzl", "venv_register_toolchains", "rules_venv_dependencies")

rules_venv_dependencies()

venv_register_toolchains()

load("@rules_venv//python/venv:repositories_transitive.bzl", "rules_venv_transitive_deps")

rules_venv_transitive_deps()