Test before push with GitHub Actions

In some cases, you might want to validate that the image works as expected before pushing it. The following workflow implements several steps to achieve this:

  1. Build and export the image to Docker
  2. Test your image
  3. Multi-platform build and push the image
name: ci

on:
  push:

env:
  TEST_TAG: user/app:test
  LATEST_TAG: user/app:latest

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ vars.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Build and export to Docker
        uses: docker/build-push-action@v6
        with:
          load: true
          tags: ${{ env.TEST_TAG }}

      - name: Test
        run: |
          docker run --rm ${{ env.TEST_TAG }}          

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          platforms: linux/amd64,linux/arm64
          push: true
          tags: ${{ env.LATEST_TAG }}

メモ

The linux/amd64 image is only built once in this workflow. The image is built once, and the following steps use the internal cache from the first Build and push step. The second Build and push step only builds linux/arm64.