Build Docker Image workflow (badges/shields)

The Build Docker Image workflow from badges/shields, explained and optimized by Latchkey.

What it does

This is the Build Docker Image workflow from the badges/shields 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: Build Docker Image
on:
  pull_request:
  push:
    branches:
      - 'gh-readonly-queue/**'

jobs:
  build-docker-image:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v7

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v4

      - name: Set Git Short SHA
        run: echo "SHORT_SHA=${GITHUB_SHA::7}" >> $GITHUB_ENV

      - name: Build
        uses: docker/build-push-action@v7
        with:
          context: .
          push: false
          tags: ghcr.io/badges/shields:pr-validation
          build-args: |
            version=${{ env.SHORT_SHA }}

The same workflow, on Latchkey

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

name: Build Docker Image
on:
  pull_request:
  push:
    branches:
      - 'gh-readonly-queue/**'
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build-docker-image:
    timeout-minutes: 30
    runs-on: latchkey-small
    steps:
      - name: Checkout
        uses: actions/checkout@v7
 
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v4
 
      - name: Set Git Short SHA
        run: echo "SHORT_SHA=${GITHUB_SHA::7}" >> $GITHUB_ENV
 
      - name: Build
        uses: docker/build-push-action@v7
        with:
          context: .
          push: false
          tags: ghcr.io/badges/shields:pr-validation
          build-args: |
            version=${{ env.SHORT_SHA }}
 

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• Cancel superseded runs when a branch or PR gets a newer push.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

2 third-party actions are referenced by a movable tag. Pin them 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:

• Container pulls and builds

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