Python package workflow (not522/ac-library-python)

The Python package workflow from not522/ac-library-python, explained and optimized by Latchkey.

CI health: D - needs work

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Source: not522/ac-library-python.github/workflows/python-package.ymlLicense CC0-1.0View source

What it does

This is the Python package workflow from the not522/ac-library-python repository, a real project running GitHub Actions. It is shown here with attribution under its CC0-1.0 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: Python package

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

jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12', '3.13']

    steps:
      - uses: actions/checkout@v4
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install .[lint,test]
      - name: Lint with flake8
        run: |
          # stop the build if there are Python syntax errors or undefined names
          flake8 atcoder tests --count --select=E9,F63,F7,F82 --show-source --statistics
          # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
          flake8 atcoder tests --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
      - name: Type check with mypy
        run: |
          mypy atcoder tests
      - name: Test with pytest
        run: |
          pytest

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: Python package
 
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:
      matrix:
        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
 
    steps:
      - uses: actions/checkout@v4
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          cache: 'pip'
          python-version: ${{ matrix.python-version }}
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install .[lint,test]
      - name: Lint with flake8
        run: |
          # stop the build if there are Python syntax errors or undefined names
          flake8 atcoder tests --count --select=E9,F63,F7,F82 --show-source --statistics
          # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
          flake8 atcoder tests --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
      - name: Type check with mypy
        run: |
          mypy atcoder tests
      - name: Test with pytest
        run: |
          pytest

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 1 job (7 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