flake8 Linting workflow (PyGCL/PyGCL)

The flake8 Linting workflow from PyGCL/PyGCL, explained and optimized by Latchkey.

What it does

This is the flake8 Linting workflow from the PyGCL/PyGCL repository, a real project running GitHub Actions. It is shown here with attribution under its Apache-2.0 license.

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

The workflow

name: flake8 Linting

on: [push, pull_request]

jobs:
  flake8-lint:
    runs-on: ${{ matrix.os }}

    strategy:
      matrix:
        os: [ ubuntu-20.04 ]
        python-version: [ 3.9 ]
        torch-version: [ 1.9.0 ]

    name: Lint
    steps:
      - name: Check out source repository
        uses: actions/checkout@v2
      - name: Set up Python environment
        uses: actions/setup-python@v2
        with:
          python-version: ${{ matrix.python-version }}
      - name: flake8 Lint
        uses: py-actions/flake8@v1
        with:
          args: "--max-complexity=5"
          max-line-length: "120"

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: flake8 Linting
 
on: [push, pull_request]
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  flake8-lint:
    timeout-minutes: 30
    runs-on: ${{ matrix.os }}
 
    strategy:
      matrix:
        os: [ ubuntu-20.04 ]
        python-version: [ 3.9 ]
        torch-version: [ 1.9.0 ]
 
    name: Lint
    steps:
      - name: Check out source repository
        uses: actions/checkout@v2
      - name: Set up Python environment
        uses: actions/setup-python@v2
        with:
          cache: 'pip'
          python-version: ${{ matrix.python-version }}
      - name: flake8 Lint
        uses: py-actions/flake8@v1
        with:
          args: "--max-complexity=5"
          max-line-length: "120"
 

What changed

• Cancel superseded runs when a branch or PR gets a newer push.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

1 third-party action is referenced by a movable tag. Pin it to the commit SHA (Latchkey resolves and applies this automatically) so a repointed tag cannot change what runs.

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