pre-commit workflow (encode/django-vanilla-views)

The pre-commit workflow from encode/django-vanilla-views, explained and optimized by Latchkey.

What it does

This is the pre-commit workflow from the encode/django-vanilla-views 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

name: pre-commit

on:
  push:
    branches:
    - master
  pull_request:

jobs:
  pre-commit:
    runs-on: ubuntu-20.04

    steps:
    - uses: actions/checkout@v2
      with:
        fetch-depth: 0

    - uses: actions/setup-python@v2

    - uses: pre-commit/action@v2.0.0
      with:
        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: pre-commit
 
on:
  push:
    branches:
    - master
  pull_request:
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  pre-commit:
    timeout-minutes: 30
    runs-on: latchkey-small
 
    steps:
    - uses: actions/checkout@v2
      with:
        fetch-depth: 0
 
    - uses: actions/setup-python@v2
      with:
        cache: 'pip'
 
    - uses: pre-commit/action@v2.0.0
      with:
        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.
• Cancel superseded runs when a branch or PR gets a newer push.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