black-action workflow (killiansheriff/LovelyPlots)

The black-action workflow from killiansheriff/LovelyPlots, explained and optimized by Latchkey.

What it does

This is the black-action workflow from the killiansheriff/LovelyPlots 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: black-action
on: [push, pull_request]
jobs:
  linter_name:
    name: runner / black formatter
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: rickstaa/action-black@v1
        with:
          black_args: ". --check"
          fail_on_error: "False"

The same workflow, on Latchkey

Removes redundant runs and caps runaway jobs. Added and changed lines are highlighted.

name: black-action
on: [push, pull_request]
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  linter_name:
    timeout-minutes: 30
    name: runner / black formatter
    runs-on: latchkey-small
    steps:
      - uses: actions/checkout@v2
      - uses: rickstaa/action-black@v1
        with:
          black_args: ". --check"
          fail_on_error: "False"

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• Cancel superseded runs when a branch or PR gets a newer push.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