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Build workflow (psf/pyperf)

The Build workflow from psf/pyperf, explained and optimized by Latchkey.

Source: psf/pyperf.github/workflows/build.ymlLicense MITView source
D
CI health grade
53/100
Health score
2
Jobs per trigger
4
Fixes in the optimized version

In short

  1. CI health: D (needs work)
  2. The optimized version below points runs-on at Latchkey managed runners and adds run de-duplication, caching, and job timeouts.

What it does

This is the Build workflow from the psf/pyperf repository, a real project running GitHub Actions. It is shown here with attribution under its MIT license.

Below, Latchkey shows a faster, safer version produced by its optimization engine.

The workflow

workflow (.yml)
name: Build

on: [push, pull_request, workflow_dispatch]

permissions: {}

env:
  FORCE_COLOR: 1

jobs:
  tox-jobs:
    strategy:
      fail-fast: false
      matrix:
        tox-job: [doc, pep8]
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          persist-credentials: false
      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
        with:
          python-version: 3.x
      - run: pip install tox
      - run: tox -e ${{ matrix.tox-job }}
  build:
    runs-on: ${{ matrix.os }}
    name: ${{ matrix.os }} - ${{ matrix.python }} ${{ matrix.build }}
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest, windows-latest, ubuntu-24.04-arm]
        python: ['3.12']
        build: ['']
        include:
          - os: ubuntu-latest
            python: 'pypy3.10'
          - os: ubuntu-latest
            python: 'pypy3.9'
          - os: ubuntu-latest
            python: '3.9'
          - os: ubuntu-latest
            python: '3.10'
          - os: ubuntu-latest
            python: '3.11'
          - os: ubuntu-latest
            python: '3.12'
          - os: ubuntu-latest
            python: '3.13-dev'
            build: 'free-threading'

    steps:
      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          persist-credentials: false
      - name: Setup Python
        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
        if: ${{ matrix.build != 'free-threading' }}
        with:
          python-version: ${{ matrix.python }}
      - name: Set up Python ${{ matrix.python }} using deadsnakes
        uses: deadsnakes/action@e640ac8743173a67cca4d7d77cd837e514bf98e8 # v3.2.0
        if: ${{ matrix.build == 'free-threading' }}
        with:
          python-version: ${{ matrix.python }}
          nogil: true
      - name: Display Python version
        run: |
          python -VV
          python -c 'import sysconfig; print("Free threading?", "Yes" if sysconfig.get_config_var("Py_GIL_DISABLED") else "No")'
      - name: Install Tox and any other packages
        run: pip install tox
      - name: Run Tox
        # Run tox using the version of Python in `PATH`
        run: tox -e py

The same workflow, on Latchkey

Estimated ~20% faster on cache hits, plus fewer wasted runs and a safer supply chain. Added and changed lines are highlighted.

workflow (.yml), optimized
name: Build

on: [push, pull_request, workflow_dispatch]

permissions: {}

env:
  FORCE_COLOR: 1

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  tox-jobs:
    timeout-minutes: 30
    strategy:
      fail-fast: false
      matrix:
        tox-job: [doc, pep8]
    runs-on: ubuntu-latest
    runs-on: latchkey-small
    steps:
      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          persist-credentials: false
      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
        with:
          cache: 'pip'
          python-version: 3.x
      - run: pip install tox
      - run: tox -e ${{ matrix.tox-job }}
  build:
    timeout-minutes: 30
    runs-on: ${{ matrix.os }}
    name: ${{ matrix.os }} - ${{ matrix.python }} ${{ matrix.build }}
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest, windows-latest, ubuntu-24.04-arm]
        python: ['3.12']
        build: ['']
        include:
          - os: ubuntu-latest
            python: 'pypy3.10'
          - os: ubuntu-latest
            python: 'pypy3.9'
          - os: ubuntu-latest
            python: '3.9'
          - os: ubuntu-latest
            python: '3.10'
          - os: ubuntu-latest
            python: '3.11'
          - os: ubuntu-latest
            python: '3.12'
          - os: ubuntu-latest
            python: '3.13-dev'
            build: 'free-threading'

    steps:
      - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          persist-credentials: false
      - name: Setup Python
        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
        if: ${{ matrix.build != 'free-threading' }}
        with:
          cache: 'pip'
          python-version: ${{ matrix.python }}
      - name: Set up Python ${{ matrix.python }} using deadsnakes
        uses: deadsnakes/action@e640ac8743173a67cca4d7d77cd837e514bf98e8 # v3.2.0
        if: ${{ matrix.build == 'free-threading' }}
        with:
          python-version: ${{ matrix.python }}
          nogil: true
      - name: Display Python version
        run: |
          python -VV
          python -c 'import sysconfig; print("Free threading?", "Yes" if sysconfig.get_config_var("Py_GIL_DISABLED") else "No")'
      - name: Install Tox and any other packages
        run: pip install tox
      - name: Run Tox
        # Run tox using the version of Python in `PATH`
        run: tox -e py

What changed

  1. Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. Each Linux x64 job moves to the Latchkey size matching its vCPU count, latchkey-small for a standard 2 vCPU runner; macOS, Windows and arm64 jobs stay as written.
  2. Cancel superseded runs when a branch or PR gets a newer push.
  3. Cache dependency installs on the setup step so they are served from cache.
  4. Add a job timeout so a hung step cannot burn hours of runner time.

Left runs-on as written on the build job: matrix.os mixes Linux with macOS and Windows and arm64, which Latchkey does not run. Point only the Linux legs at Latchkey, for example with a matrix include entry that sets the runner.

What Latchkey heals here

This workflow has steps that commonly fail on transient issues (network, registries, flaky browsers). On Latchkey managed runners they are detected, retried, and self-healed instead of failing your build:

  • Dependency installs

This workflow runs 2 jobs (6 with the matrix expanded) per trigger. 3 of the 6 run on a standard GitHub-hosted Linux x64 runner, which in a private repository bills $0.006 a minute against $0.0025 on latchkey-small, 58% lower; in a public repository like this one they are free. 3 of the 6 run on macOS and Windows and arm64, which Latchkey does not offer, so those stay where they are. Estimate the monthly difference with your own run counts.

Actions used in this workflow

  • actions/checkout
  • actions/setup-python
  • deadsnakes/action

Frequently asked questions

What does the Build workflow (psf/pyperf) workflow do?
This is the Build workflow from the psf/pyperf repository, a real project running GitHub Actions. It is shown here with attribution under its MIT license.
What CI health grade does this workflow get?
This Python workflow grades D. Paste your own workflow into the Latchkey grader to see its grade and the exact fixes.
How can I improve this Python workflow?
Add run de-duplication, caching, and job timeouts. Latchkey applies these automatically on managed runners when you point runs-on at Latchkey.

References