GitHub Actions: Pure Python wheels

We will cover binary wheels on the next page, but if you do not have a compiled extension, this is called a universal (pure Python) package, and the procedure to make a “built” wheel is simple. At the end of this page, there is a recipe that can often be used exactly for pure Python wheels (if the previous recommendations were followed).

Why make a wheel when there is nothing to compile? There are a multitude of reasons that a wheel is better than only providing an sdist:

Wheels do not run setup.py, but simply install files into locations

Lower install requirements - users don’t need your setup tools

Faster installs

Safer installs - no arbitrary code execution

Highly consistent installs

Wheels pre-compile bytecode when they install

Initial import is not slower than subsequent import

Less chance of a permission issue

You can look in the .whl (it’s a .zip, really) and see where everything is going to go

Job setup

name: CD

on:
  workflow_dispatch:
  release:
    types:
      - published

jobs:

This will run when you manually trigger a build (workflow_dispatch), or when you publish a release. Later, we will make sure that the actual publish step requires the event to be a publish event, so that manual triggers (and branches/PRs, if those are enabled).

If you want tags instead of releases, you can add the on: push: tags: "v*" key instead of the releases - however, please remember to make a GitHub release of your tag! It shows up in the GUI and it notifies anyone watching releases(-only). You will also need to change the event filter below.

You can merge the CI job and the CD job if you want. To do that, preferably with the name “CI/CD”, you can just combine the two on dicts.

Distribution: Pure Python wheels

dist:
  runs-on: ubuntu-latest
  steps:
    - uses: actions/checkout@v4
      with:
        fetch-depth: 0

    - name: Build SDist and wheel
      run: pipx run build

    - uses: actions/upload-artifact@v4
      with:
        name: Packages
        path: dist/*

    - name: Check metadata
      run: pipx run twine check dist/*

We use PyPA-Build, a new build tool designed to make building wheels and SDists easy. It run a PEP 517 backend and can get PEP 518 requirements even for making SDists.

By default this will make an SDist and a wheel from the package in the current directory, and they will be placed in ./dist. You can only build SDist (-s), only build wheel (-w), change the output folder (-o <dir>) or give a different input folder if you want.

You could use the setup-python action, install build and twine with pip, and then use python -m build or pyproject-build, but it’s better to use pipx to install and run python applications. Pipx is provided by default by GitHub Actions (in fact, they use it to setup other applications).

We upload the artifact just to make it available via the GitHub PR/Checks API. You can download a file to test locally if you want without making a release.

As of upload-artifact@v4, the artifact name must be unique. Extending an existing artifact is no longer supported.

We also add an optional check using twine for the metadata (it will be tested later in the upload action for the release job, as well).

All-in-one action

There is an all-in-one action that does all the work for you for a pure Python package, including extra pre-upload checks & nice GitHub summaries.
steps:
  - uses: actions/checkout@v4
  - uses: hynek/build-and-inspect-python-package@v2
The artifact it produces is named Packages, so that’s what you need to use later to publish. This will be used instead of the manual steps below.

And then, you need a release job:

publish:
  needs: [dist]
  environment: pypi
  permissions:
    id-token: write
    attestations: write
    contents: read
  runs-on: ubuntu-latest
  if: github.event_name == 'release' && github.event.action == 'published'
  steps:
    - uses: actions/download-artifact@v4
      with:
        name: Packages
        path: dist

    - name: Generate artifact attestation for sdist and wheel
      uses: actions/attest-build-provenance@v1.4.4
      with:
        subject-path: "dist/*"

    - uses: pypa/gh-action-pypi-publish@release/v1

When you make a GitHub release in the web UI, we publish to PyPI. You’ll just need to tell PyPI which org, repo, workflow, and set the pypi environment to allow pushes from GitHub. If it’s the first time you’ve published a package, go to the PyPI trusted publisher docs for instructions on preparing PyPI to accept your initial package publish.

We are also generating artifact attestations, which can allow users to verify that the artifacts were built on your actions.

Complete recipe

This can be used on almost any package with a standard .github/workflows/cd.yml recipe. This works because pyproject.toml describes exactly how to build your package, hence all packages build exactly via the same interface:

name: CD

on:
  workflow_dispatch:
  pull_request:
  push:
    branches:
      - main
  release:
    types:
      - published

jobs:
  dist:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - uses: hynek/build-and-inspect-python-package@v2

  publish:
    needs: [dist]
    environment: pypi
    permissions:
      id-token: write
      attestations: write
      contents: read
    runs-on: ubuntu-latest
    if: github.event_name == 'release' && github.event.action == 'published'

    steps:
      - uses: actions/download-artifact@v4
        with:
          name: Packages
          path: dist

      - name: Generate artifact attestation for sdist and wheel
        uses: actions/attest-build-provenance@v1.4.4
        with:
          subject-path: "dist/*"

      - uses: pypa/gh-action-pypi-publish@release/v1