setup-buildx-action VS metadata-action

Good luck running this locally. There's no script code to speak of, just references to external "actions" and parameters (for example, https://github.com/docker/setup-buildx-action).

Some CI platforms are just a simple glue layer (Gitlab CI - which I prefer - is one of them), but in most cases Github CI is not. Maybe it adds to the author frustration?

Set up Docker Buildx: We will use the docker/setup-buildx-action action to set up Docker Buildx.

There’s an amazing docker/bake-action which makes it insanely easy to build all of your containers in the most optimal way. Since we’ve set the group “default” block in the docker-bake.hcl, config is very minimal. One step in your GitHub Action workflow file will build all of your images and will push all of your cache layers, tag all of your containers, and push all your final images. You’ll still have to do things like checkout the code and don’t forget that you’ll want to use the docker/setup-buildx-action since bake is a buildx feature. There’s one quick gotcha for the actual docker/bake-action. We don’t want to push PR builds and we don’t want to pollute the cache with PR builds.

To be clear, that article does NOT provide a solution for avoiding QEMU. I suggested it because it describes "the hard way" to get a single image multi-arch image. The github action crazy-max/ghaction-docker-buildx has been archived and replaced by docker/setup-qemu-action and docker/setup-buildx-action, which it seems like you were already using.

Third step is docker/setup-buildx-action configures buildx, which is a Docker CLI plugin that provides enhanced build capabilities.

We then use the docker/setup-buildx-action action to initialize an environment to build Docker images:

The setup-buildx-action configures Docker Buildx to create a builder instance for running the image build. The following step build-push-action, makes use of that instance to build your Docker image. The build-push-action supports all of the features provided by BuildKit out of the box. In our simple example, we are only specifying the Docker context, but more advanced features like SSH, secrets, and build args are supported.

# Get the repository's code - name: Checkout uses: actions/checkout@v2 # https://github.com/docker/setup-qemu-action - name: Set up QEMU uses: docker/setup-qemu-action@v1 # https://github.com/docker/setup-buildx-action - name: Set up Docker Buildx id: buildx uses: docker/setup-buildx-action@v1

docker/setup-buildx-action@v1 - we use it to setup the docker builder

name: Lint and Dockerize the app on: push: branches: [master] pull_request: branches: [master] env: # Use docker.io for Docker Hub if empty REGISTRY: docker.io # github.repository as / IMAGE_NAME: ${{ github.repository }} jobs: build: runs-on: ubuntu-latest permissions: contents: read packages: write steps: - name: Checkout repository uses: actions/checkout@v2 - name: Set up Google Cloud uses: google-github-actions/[email protected] with: project_id: ${{ secrets.GCP_PROJECT_ID }} service_account_key: ${{ secrets.GCP_SA_KEY }} # Login against a Docker registry except on PR # https://github.com/docker/login-action - name: Log into registry ${{ env.REGISTRY }} # if: github.event_name != 'pull_request' uses: docker/login-action@v1 with: username: ${{ secrets.DOCKER_USERNAME }} password: ${{ secrets.DOCKER_PASSWORD }} # Extract metadata (tags, labels) for Docker # https://github.com/docker/metadata-action #- name: Extract Docker metadata # id: meta # uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38 # with: # images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }} # Build and push Docker image with Buildx (don't push on PR) # https://github.com/docker/build-push-action - name: Build and push Docker image uses: docker/build-push-action@v2 with: context: ./ tags: ${{ secrets.DOCKER_USERNAME }}/magga:latest push: true file: ./Dockerfile - name: Image digest run: echo

docker/metadata-action@v4 to extract metadata (tags, labels) from Git reference and GitHub events for Docker.

5d. Extract metadata (tags, labels) for Docker: This step extracts metadata for Docker. The step uses the docker/metadata-action action to extract the metadata. The action is used to extract metadata from Dockerfiles and docker-compose files. The action outputs two variables: tags and labels. The tags variable contains the tags for the Docker image. The labels variable contains the labels for the Docker image. You can read more about the docker/metadata-action action here.

name: Docker Image Publish on: push: branches: [ "main" ] # Publish semver tags as releases. tags: [ 'v*.*.*' ] pull_request: branches: [ "main" ] env: # Use docker.io for Docker Hub if empty REGISTRY: ghcr.io # github.repository as / IMAGE_NAME: ${{ github.repository }} jobs: build: runs-on: ubuntu-latest permissions: contents: read packages: write # This is used to complete the identity challenge # with sigstore/fulcio when running outside of PRs. id-token: write steps: - name: Checkout repository uses: actions/checkout@v3 # Install the cosign tool except on PR # https://github.com/sigstore/cosign-installer - name: Install cosign if: github.event_name != 'pull_request' uses: sigstore/cosign-installer@f3c664df7af409cb4873aa5068053ba9d61a57b6 #v2.6.0 with: cosign-release: 'v1.11.0' # Workaround: https://github.com/docker/build-push-action/issues/461 - name: Setup Docker buildx uses: docker/setup-buildx-action@v2 # Login against a Docker registry except on PR # https://github.com/docker/login-action - name: Log into registry ${{ env.REGISTRY }} if: github.event_name != 'pull_request' uses: docker/login-action@28218f9b04b4f3f62068d7b6ce6ca5b26e35336c with: registry: ${{ env.REGISTRY }} username: ${{ github.actor }} password: ${{ secrets.GITHUB_TOKEN }} # Extract metadata (tags, labels) for Docker # https://github.com/docker/metadata-action - name: Extract Docker metadata id: meta uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38 with: images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }} # Build and push Docker image with Buildx (don't push on PR) # https://github.com/docker/build-push-action - name: Build and push Docker image id: build-and-push uses: docker/build-push-action@v4 with: context: "{{defaultContext}}:src" push: ${{ github.event_name != 'pull_request' }} # Don't push on PR tags: ${{ steps.meta.outputs.tags }} labels: ${{ steps.meta.outputs.labels }} cache-from: type=gha cache-to: type=gha,mode=max

Extract metadata (tags, labels) for Docker: We will use the docker/metadata-action action to extract the metadata for the Docker image. We will use the following inputs:

If using Github actions, the Docker metadata-action catches and fixes issues like that: https://github.com/docker/metadata-action

name: Docker # This workflow uses actions that are not certified by GitHub. # They are provided by a third-party and are governed by # separate terms of service, privacy policy, and support # documentation. on: push: branches: [ "main" ] # Publish semver tags as releases. tags: [ 'v*.*.*' ] pull_request: branches: [ "main" ] paths: - src/MamisSolidarias.WebAPI.Campaigns/Dockerfile - .github/workflows/docker-publish.yml workflow_dispatch: env: # Use docker.io for Docker Hub if empty REGISTRY: ghcr.io IMAGE_NAME: mamis-solidarias/campaigns jobs: build: runs-on: ubuntu-latest permissions: contents: read packages: write # This is used to complete the identity challenge # with sigstore/fulcio when running outside of PRs. id-token: write steps: - name: Checkout repository uses: actions/checkout@v3 # Install the cosign tool except on PR # https://github.com/sigstore/cosign-installer - name: Install cosign if: github.event_name != 'pull_request' uses: sigstore/cosign-installer@main with: cosign-release: 'v1.13.1' - name: Set up QEMU uses: docker/setup-qemu-action@v2 with: platforms: 'arm64' # Workaround: https://github.com/docker/build-push-action/issues/461 - name: Setup Docker buildx uses: docker/setup-buildx-action@v2 # Login against a Docker registry except on PR # https://github.com/docker/login-action - name: Log into registry ${{ env.REGISTRY }} if: github.event_name != 'pull_request' uses: docker/login-action@v2 with: registry: ${{ env.REGISTRY }} username: ${{ github.actor }} password: ${{ secrets.GITHUB_TOKEN }} # Extract metadata (tags, labels) for Docker # https://github.com/docker/metadata-action - name: Extract Docker metadata id: meta uses: docker/metadata-action@v4 with: images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }} tags: | type=schedule type=ref,event=branch type=ref,event=pr type=semver,pattern={{version}} type=semver,pattern={{major}}.{{minor}} type=semver,pattern={{major}} type=sha # Build and push Docker image with Buildx (don't push on PR) # https://github.com/docker/build-push-action - name: Build and push Docker image id: build-and-push uses: docker/build-push-action@v3 with: context: . platforms: linux/amd64, linux/arm64 file: src/MamisSolidarias.WebAPI.Campaigns/Dockerfile push: ${{ github.event_name != 'pull_request' }} tags: ${{ steps.meta.outputs.tags }} labels: ${{ steps.meta.outputs.labels }} # Sign the resulting Docker image digest except on PRs. # This will only write to the public Rekor transparency log when the Docker # repository is public to avoid leaking data. If you would like to publish # transparency data even for private images, pass --force to cosign below. # https://github.com/sigstore/cosign - name: Sign the published Docker image if: ${{ github.event_name != 'pull_request' }} env: COSIGN_EXPERIMENTAL: "true" # This step uses the identity token to provision an ephemeral certificate # against the sigstore community Fulcio instance. run: echo "${{ steps.meta.outputs.tags }}" | xargs -I {} cosign sign {}@${{ steps.build-and-push.outputs.digest }}

docker/metadata-action to figure out tags and labels for images build from (newly-added) git tags automatically (with semver support).

So we'll use the extremely useful docker/metadata-action@v3 for preparing those tags for us. Check out https://github.com/docker/metadata-action for more example tagging strategies. The documentation is great!

name: Docker Publish on: push: branches: [ main ] tags: [ 'v*' ] pull_request: branches: [ main ] env: REGISTRY: ghcr.io # github.repository as / IMAGE_NAME: ${{ github.repository }} jobs: build: runs-on: ubuntu-latest permissions: contents: read packages: write steps: - name: Checkout repository uses: actions/checkout@v2 # https://github.com/docker/login-action - name: Log into registry ${{ env.REGISTRY }} if: github.event_name != 'pull_request' uses: docker/login-action@v1 with: registry: ${{ env.REGISTRY }} username: ${{ github.actor }} password: ${{ secrets.GITHUB_TOKEN }} # https://github.com/docker/metadata-action - name: Extract Docker metadata id: meta uses: docker/metadata-action@v3 with: images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }} # https://github.com/docker/build-push-action - name: Build and push Docker image uses: docker/build-push-action@v2 with: context: . push: ${{ github.event_name != 'pull_request' }} tags: ${{ steps.meta.outputs.tags }} labels: ${{ steps.meta.outputs.labels }}