Python package workflow (mautrix/python)

The Python package workflow from mautrix/python, explained and optimized by Latchkey.

CI health: F - at risk

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Source: mautrix/python.github/workflows/python-package.ymlLicense MPL-2.0View source

What it does

This is the Python package workflow from the mautrix/python repository, a real project running GitHub Actions. It is shown here with attribution under its MPL-2.0 license.

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

The workflow

workflow (.yml)

name: Python package

on: [push, pull_request]

jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]

    steps:
    - uses: actions/checkout@v7
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v6
      with:
        python-version: ${{ matrix.python-version }}
    - name: Install libolm
      run: sudo apt-get install libolm3
    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip
        python -m pip install python-olm --extra-index-url https://gitlab.matrix.org/api/v4/projects/27/packages/pypi/simple
        python -m pip install .[test]
    - name: Test with pytest
      run: |
        export MEOW_TEST_PG_URL=postgres://meow:meow@localhost/meow
        pytest

    services:
      postgres:
        image: postgres
        env:
          POSTGRES_USER: meow
          POSTGRES_PASSWORD: meow
          POSTGRES_DB: meow
        ports:
          - 5432:5432
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5

  lint:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v7
    - uses: actions/setup-python@v6
      with:
        python-version: "3.14"
    - uses: isort/isort-action@master
      with:
        sortPaths: "./mautrix"
    - uses: psf/black@stable
      with:
        src: "./mautrix"
        version: "26.5.1"
    - name: pre-commit
      run: |
        pip install pre-commit
        pre-commit run -av trailing-whitespace
        pre-commit run -av end-of-file-fixer
        pre-commit run -av check-yaml
        pre-commit run -av check-added-large-files

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: Python package
 
on: [push, pull_request]
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build:
    timeout-minutes: 30
    runs-on: latchkey-small
    strategy:
      fail-fast: false
      matrix:
        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
 
    steps:
    - uses: actions/checkout@v7
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v6
      with:
        cache: 'pip'
        python-version: ${{ matrix.python-version }}
    - name: Install libolm
      run: sudo apt-get install libolm3
    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip
        python -m pip install python-olm --extra-index-url https://gitlab.matrix.org/api/v4/projects/27/packages/pypi/simple
        python -m pip install .[test]
    - name: Test with pytest
      run: |
        export MEOW_TEST_PG_URL=postgres://meow:meow@localhost/meow
        pytest
 
    services:
      postgres:
        image: postgres
        env:
          POSTGRES_USER: meow
          POSTGRES_PASSWORD: meow
          POSTGRES_DB: meow
        ports:
          - 5432:5432
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
 
  lint:
    timeout-minutes: 30
    runs-on: latchkey-small
    steps:
    - uses: actions/checkout@v7
    - uses: actions/setup-python@v6
      with:
        cache: 'pip'
        python-version: "3.14"
    - uses: isort/isort-action@master
      with:
        sortPaths: "./mautrix"
    - uses: psf/black@stable
      with:
        src: "./mautrix"
        version: "26.5.1"
    - name: pre-commit
      run: |
        pip install pre-commit
        pre-commit run -av trailing-whitespace
        pre-commit run -av end-of-file-fixer
        pre-commit run -av check-yaml
        pre-commit run -av check-added-large-files

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.
Cancel superseded runs when a branch or PR gets a newer push.
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.

2 third-party actions are referenced by a movable tag. Pin them to the commit SHA (Latchkey resolves and applies this automatically) so a repointed tag cannot change what runs.

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. 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