Build and push docker images workflow (CERT-Polska/karton)

The Build and push docker images workflow from CERT-Polska/karton, explained and optimized by Latchkey.

What it does

This is the Build and push docker images workflow from the CERT-Polska/karton repository, a real project running GitHub Actions. It is shown here with attribution under its BSD-3-Clause license.

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

The workflow

name: Build and push docker images
on:
  push:
    branches:
      - master
  pull_request:
    branches:
      - master
jobs:
  build_core:
    name: Build image
    runs-on: ubuntu-latest
    steps:
      - name: Check out repository
        uses: actions/checkout@v4
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v2
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v2
      - name: Login to Docker Hub
        if: ${{ github.event_name == 'push' }}
        uses: docker/login-action@v2
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}
      - name: Build and push the image
        uses: docker/build-push-action@v4
        with:
          tags: |
            certpl/karton-system:${{ github.sha }}
            certpl/karton-system:master
          push: ${{ github.event_name == 'push' }}
          # Flux v1 doesn't support OCI-compliant manifests
          provenance: false
          platforms: linux/arm64,linux/amd64

The same workflow, on Latchkey

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

name: Build and push docker images
on:
  push:
    branches:
      - master
  pull_request:
    branches:
      - master
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build_core:
    timeout-minutes: 30
    name: Build image
    runs-on: latchkey-small
    steps:
      - name: Check out repository
        uses: actions/checkout@v4
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v2
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v2
      - name: Login to Docker Hub
        if: ${{ github.event_name == 'push' }}
        uses: docker/login-action@v2
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}
      - name: Build and push the image
        uses: docker/build-push-action@v4
        with:
          tags: |
            certpl/karton-system:${{ github.sha }}
            certpl/karton-system:master
          push: ${{ github.event_name == 'push' }}
          # Flux v1 doesn't support OCI-compliant manifests
          provenance: false
          platforms: linux/arm64,linux/amd64
 

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.

4 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