decorator workflow (micheles/decorator)

The decorator workflow from micheles/decorator, explained and optimized by Latchkey.

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Source: micheles/decorator.github/workflows/python-package.ymlLicense BSD-2-ClauseView source

What it does

This is the decorator workflow from the micheles/decorator repository, a real project running GitHub Actions. It is shown here with attribution under its BSD-2-Clause license.

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

The workflow

workflow (.yml)

# This workflow will install Python dependencies, run tests and lint with a variety of Python versions
# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions

name: decorator

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

jobs:
  build:

    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13', '3.14']

    steps:
    - uses: actions/checkout@v6
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v6
      with:
        python-version: ${{ matrix.python-version }}
        allow-prereleases: true
    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip
        python -m pip install codespell flake8
        python -m pip install -e .
    - run: codespell --ignore-words-list="assertIn,ba,claus,vas" --quiet-level=2
    - run: flake8 . --count --ignore=E122,E226,E265,E741,E742 --max-complexity=23 --max-line-length=124 --show-source --statistics
    - run: python tests/test.py -v

  stubtest:

    runs-on: ubuntu-latest
    strategy:
      fail-fast: false

    steps:
    - uses: actions/checkout@v6
    - name: Set up Python 3.x
      uses: actions/setup-python@v6
      with:
        python-version: 3.x
        allow-prereleases: true
    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip
        python -m pip install mypy
        python -m pip install -e .
    - run: |
        python -m mypy.stubtest decorator
        python -m mypy src/decorator/__init__.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.

# This workflow will install Python dependencies, run tests and lint with a variety of Python versions
# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
 
name: decorator
 
on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]
 
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: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13', '3.14']
 
    steps:
    - uses: actions/checkout@v6
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v6
      with:
        cache: 'pip'
        python-version: ${{ matrix.python-version }}
        allow-prereleases: true
    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip
        python -m pip install codespell flake8
        python -m pip install -e .
    - run: codespell --ignore-words-list="assertIn,ba,claus,vas" --quiet-level=2
    - run: flake8 . --count --ignore=E122,E226,E265,E741,E742 --max-complexity=23 --max-line-length=124 --show-source --statistics
    - run: python tests/test.py -v
 
  stubtest:
    timeout-minutes: 30
 
    runs-on: latchkey-small
    strategy:
      fail-fast: false
 
    steps:
    - uses: actions/checkout@v6
    - name: Set up Python 3.x
      uses: actions/setup-python@v6
      with:
        cache: 'pip'
        python-version: 3.x
        allow-prereleases: true
    - name: Install dependencies
      run: |
        python -m pip install --upgrade pip
        python -m pip install mypy
        python -m pip install -e .
    - run: |
        python -m mypy.stubtest decorator
        python -m mypy src/decorator/__init__.py

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.

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 (8 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