PEP8 and mypy workflow (christgau/wsdd)

The PEP8 and mypy workflow from christgau/wsdd, explained and optimized by Latchkey.

What it does

This is the PEP8 and mypy workflow from the christgau/wsdd 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

name: "PEP8 and mypy"

on:
  push:
    branches: ["master", "feat/workflows"]
  pull_request:
    branches: ["master", "feat/workflows"]
  schedule:
    - cron: '0 0 * * */10'

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v1

    - name: Set up Python 3.10
      uses: actions/setup-python@v1
      with:
        python-version: "3.10"

    - name: Python 3.10 syntax check
      run: python -m py_compile src/wsdd.py

    - name: Lint with flake8
      run: |
        pip install flake8
        flake8 --count --show-source --statistics src

    - name: mypy type check
      run: |
        pip install mypy==1.13.0
        test/linting/mypy.sh

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: "PEP8 and mypy"
 
on:
  push:
    branches: ["master", "feat/workflows"]
  pull_request:
    branches: ["master", "feat/workflows"]
  schedule:
    - cron: '0 0 * * */10'
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build:
    timeout-minutes: 30
    runs-on: latchkey-small
 
    steps:
    - uses: actions/checkout@v1
 
    - name: Set up Python 3.10
      uses: actions/setup-python@v1
      with:
        cache: 'pip'
        python-version: "3.10"
 
    - name: Python 3.10 syntax check
      run: python -m py_compile src/wsdd.py
 
    - name: Lint with flake8
      run: |
        pip install flake8
        flake8 --count --show-source --statistics src
 
    - name: mypy type check
      run: |
        pip install mypy==1.13.0
        test/linting/mypy.sh
 

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• Cancel superseded runs when a branch or PR gets a newer push.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 per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.

Actions used in this workflow