Automatic lint workflow (asteroid-team/asteroid)

The Automatic lint workflow from asteroid-team/asteroid, explained and optimized by Latchkey.

What it does

This is the Automatic lint workflow from the asteroid-team/asteroid 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: Automatic lint

on:
  issue_comment:
    types: [created]

jobs:
  build:
    name: Lint code base
    if: github.event.issue.pull_request != '' && contains(github.event.comment.body, '/lint')
    runs-on: ubuntu-latest

    steps:
      - name: Set up Python 3.13
        uses: actions/setup-python@v6
        with:
          python-version: 3.13

      - uses: actions/checkout@v5
      - run: git pull
      - run: pip install black==25.9.0 flake8
      - run: python -m black --config=pyproject.toml asteroid tests egs
      - name: Commit changes
        uses: EndBug/add-and-commit@v9
        with:
          message: "[Bot] Lint PR"
          add: "*.py"
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

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: Automatic lint
 
on:
  issue_comment:
    types: [created]
 
jobs:
  build:
    timeout-minutes: 30
    name: Lint code base
    if: github.event.issue.pull_request != '' && contains(github.event.comment.body, '/lint')
    runs-on: latchkey-small
 
    steps:
      - name: Set up Python 3.13
        uses: actions/setup-python@v6
        with:
          cache: 'pip'
          python-version: 3.13
 
      - uses: actions/checkout@v5
      - run: git pull
      - run: pip install black==25.9.0 flake8
      - run: python -m black --config=pyproject.toml asteroid tests egs
      - name: Commit changes
        uses: EndBug/add-and-commit@v9
        with:
          message: "[Bot] Lint PR"
          add: "*.py"
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 

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.
• 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.

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