CI workflow (adamchainz/time-machine)

The CI workflow from adamchainz/time-machine, explained and optimized by Latchkey.

CI health: C - fair

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Source: adamchainz/time-machine.github/workflows/main.ymlLicense MITView source

What it does

This is the CI workflow from the adamchainz/time-machine 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: CI

on:
  push:
    branches:
    - main
    tags:
    - '**'
  pull_request:

concurrency:
  group: ${{ github.head_ref || github.run_id }}
  cancel-in-progress: true

jobs:
  tests:
    name: Python ${{ matrix.python-version }}
    runs-on: ubuntu-24.04

    strategy:
      matrix:
        python-version:
        - '3.10'
        - '3.11'
        - '3.12'
        - '3.13'
        - '3.13t'
        - '3.14'
        - '3.14t'

    steps:
    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      with:
        persist-credentials: false

    - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
      with:
        python-version: ${{ matrix.python-version }}
        allow-prereleases: true

    - name: Install uv
      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
      with:
        enable-cache: true

    - name: Run tox targets for ${{ matrix.python-version }}
      run: uvx --with tox-uv tox run -f py$(echo ${{ matrix.python-version }} | tr -d .)

    - name: Upload coverage data
      uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
      with:
        name: coverage-data-${{ matrix.python-version }}
        path: '${{ github.workspace }}/.coverage/*'
        include-hidden-files: true
        if-no-files-found: error

  coverage:
    name: Coverage
    runs-on: ubuntu-24.04
    needs: tests
    if: always()
    steps:
    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      with:
        persist-credentials: false

    - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
      with:
        python-version: '3.13'

    - name: Install uv
      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0

    - name: Install dependencies
      run: uv pip install --system coverage[toml]

    - name: Download data
      uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
      with:
        path: .coverage
        pattern: coverage-data-*
        merge-multiple: true

    - name: Combine coverage and fail if it's <100%
      run: |
        python -m coverage combine
        python -m coverage html --skip-covered --skip-empty
        python -m coverage report --fail-under=100
        echo "## Coverage summary" >> $GITHUB_STEP_SUMMARY
        python -m coverage report --format=markdown >> $GITHUB_STEP_SUMMARY

    - name: Upload HTML report
      if: failure()
      uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
      with:
        name: html-report
        path: htmlcov

  build:
    name: Build wheels for ${{ matrix.os }}-${{ matrix.arch }}
    if: startsWith(github.ref, 'refs/tags/') || github.ref == 'refs/heads/main' || contains(github.event.pull_request.labels.*.name, 'Build')

    strategy:
      fail-fast: false
      matrix:
        include:
        - os: linux
          arch: aarch64
        - os: linux
          arch: x86_64
        - os: macos
          arch: arm64
        - os: macos
          arch: x86_64
        - os: windows
          arch: AMD64
        - os: windows
          arch: ARM64

    runs-on: ${{ (matrix.os == 'linux' && matrix.arch == 'aarch64' && 'ubuntu-24.04-arm') || (matrix.os == 'linux' && 'ubuntu-24.04') || (matrix.os == 'macos' && matrix.arch == 'arm64' && 'macos-15') || (matrix.os == 'macos' && matrix.arch == 'x86_64' && 'macos-15-intel') || (matrix.os == 'windows' && matrix.arch == 'ARM64' && 'windows-11-arm') || (matrix.os == 'windows' && 'windows-2022') || 'unknown' }}

    steps:
    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      with:
        persist-credentials: false

    - uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
      with:
        enable-cache: false

    - name: Build sdist
      if: matrix.os == 'linux' && matrix.arch == 'x86_64'
      run: uv build --sdist

    - name: Build wheels
      run: uv run --only-group build cibuildwheel --output-dir dist

    - run: ${{ (matrix.os == 'windows' && 'dir') || 'ls -lh' }} dist/

    - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
      with:
        name: dist-${{ matrix.os }}-${{ matrix.arch }}
        path: dist

  release:
    needs: [coverage, build]
    if: success() && startsWith(github.ref, 'refs/tags/')
    runs-on: ubuntu-24.04
    environment: release

    permissions:
      contents: read
      id-token: write

    steps:
    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      with:
        persist-credentials: false

    - name: get dist artifacts
      uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
      with:
        merge-multiple: true
        pattern: dist-*
        path: dist

    - uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # v1.14.0

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.

name: CI
 
on:
  push:
    branches:
    - main
    tags:
    - '**'
  pull_request:
 
concurrency:
  group: ${{ github.head_ref || github.run_id }}
  cancel-in-progress: true
 
jobs:
  tests:
    timeout-minutes: 30
    name: Python ${{ matrix.python-version }}
    runs-on: latchkey-small
 
    strategy:
      matrix:
        python-version:
        - '3.10'
        - '3.11'
        - '3.12'
        - '3.13'
        - '3.13t'
        - '3.14'
        - '3.14t'
 
    steps:
    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      with:
        persist-credentials: false
 
    - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
      with:
        cache: 'pip'
        python-version: ${{ matrix.python-version }}
        allow-prereleases: true
 
    - name: Install uv
      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
      with:
        enable-cache: true
 
    - name: Run tox targets for ${{ matrix.python-version }}
      run: uvx --with tox-uv tox run -f py$(echo ${{ matrix.python-version }} | tr -d .)
 
    - name: Upload coverage data
      uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
      with:
        name: coverage-data-${{ matrix.python-version }}
        path: '${{ github.workspace }}/.coverage/*'
        include-hidden-files: true
        if-no-files-found: error
 
  coverage:
    timeout-minutes: 30
    name: Coverage
    runs-on: latchkey-small
    needs: tests
    if: always()
    steps:
    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      with:
        persist-credentials: false
 
    - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
      with:
        cache: 'pip'
        python-version: '3.13'
 
    - name: Install uv
      uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
 
    - name: Install dependencies
      run: uv pip install --system coverage[toml]
 
    - name: Download data
      uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
      with:
        path: .coverage
        pattern: coverage-data-*
        merge-multiple: true
 
    - name: Combine coverage and fail if it's <100%
      run: |
        python -m coverage combine
        python -m coverage html --skip-covered --skip-empty
        python -m coverage report --fail-under=100
        echo "## Coverage summary" >> $GITHUB_STEP_SUMMARY
        python -m coverage report --format=markdown >> $GITHUB_STEP_SUMMARY
 
    - name: Upload HTML report
      if: failure()
      uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
      with:
        name: html-report
        path: htmlcov
 
  build:
    timeout-minutes: 30
    name: Build wheels for ${{ matrix.os }}-${{ matrix.arch }}
    if: startsWith(github.ref, 'refs/tags/') || github.ref == 'refs/heads/main' || contains(github.event.pull_request.labels.*.name, 'Build')
 
    strategy:
      fail-fast: false
      matrix:
        include:
        - os: linux
          arch: aarch64
        - os: linux
          arch: x86_64
        - os: macos
          arch: arm64
        - os: macos
          arch: x86_64
        - os: windows
          arch: AMD64
        - os: windows
          arch: ARM64
 
    runs-on: ${{ (matrix.os == 'linux' && matrix.arch == 'aarch64' && 'ubuntu-24.04-arm') || (matrix.os == 'linux' && 'ubuntu-24.04') || (matrix.os == 'macos' && matrix.arch == 'arm64' && 'macos-15') || (matrix.os == 'macos' && matrix.arch == 'x86_64' && 'macos-15-intel') || (matrix.os == 'windows' && matrix.arch == 'ARM64' && 'windows-11-arm') || (matrix.os == 'windows' && 'windows-2022') || 'unknown' }}
 
    steps:
    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      with:
        persist-credentials: false
 
    - uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
      with:
        enable-cache: false
 
    - name: Build sdist
      if: matrix.os == 'linux' && matrix.arch == 'x86_64'
      run: uv build --sdist
 
    - name: Build wheels
      run: uv run --only-group build cibuildwheel --output-dir dist
 
    - run: ${{ (matrix.os == 'windows' && 'dir') || 'ls -lh' }} dist/
 
    - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
      with:
        name: dist-${{ matrix.os }}-${{ matrix.arch }}
        path: dist
 
  release:
    timeout-minutes: 30
    needs: [coverage, build]
    if: success() && startsWith(github.ref, 'refs/tags/')
    runs-on: latchkey-small
    environment: release
 
    permissions:
      contents: read
      id-token: write
 
    steps:
    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
      with:
        persist-credentials: false
 
    - name: get dist artifacts
      uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
      with:
        merge-multiple: true
        pattern: dist-*
        path: dist
 
    - uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # v1.14.0

What changed

Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. This example uses latchkey-small; pick the runner size that fits the job.
Cache dependency installs on the setup step so they are served from cache.
Add a job timeout so a hung step cannot burn hours of runner time.

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 4 jobs (10 with the matrix expanded) per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.

Actions used in this workflow

actions/checkout actions/setup-python astral-sh/setup-uv actions/upload-artifact actions/download-artifact