free-games-claimer/.github/workflows/docker.yml

name: Build and push Docker image (amd64, arm64 to hub.docker.com and ghcr.io)

on:
  workflow_dispatch: # allows manual trigger
  push: # push on branch
    branches: [main, dev]
    paths: # ignore changes to .md files
      - "**"
      - "!*.md"
      # - '!.github/**'
  pull_request: # runs when opened/reopened or when the head branch is updated

permissions:
  contents: read
  packages: write

env:
  BRANCH: ${{ github.head_ref || github.ref_name }} # head_ref/base_ref are only set for PRs, for branches ref_name will be used

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
      - name: Set environment variables
        run: |
          echo "NOW=$(date -R)" >> "$GITHUB_ENV" # date -Iseconds; date +'%Y-%m-%dT%H:%M:%S'
          if [[ "$BRANCH" == "main" ]]; then
            echo "IMAGE_TAG=latest" >> "$GITHUB_ENV"
          else
            echo "IMAGE_TAG=$BRANCH" >> "$GITHUB_ENV"
          fi
      - name: Extract metadata for Docker (tags, labels)
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: |
            ${{ secrets.DOCKERHUB_USERNAME }}/free-games-claimer
            ghcr.io/${{ github.actor }}/free-games-claimer
          tags: |
            type=ref,event=branch
            type=ref,event=pr
            # use docker tag 'latest' for the default branch (default is to only use it for the latest git tag)
            type=raw,value=latest,enable={{is_default_branch}}
          labels: |
            org.opencontainers.image.created={{commit_date 'YYYY-MM-DDTHH:mm:ss.SSS[Z]'}}
        env:
          # otherwise labels are not shown on GitHub due to multi-arch image: https://docs.github.com/en/packages/working-with-a-github-packages-registry/working-with-the-container-registry#adding-a-description-to-multi-arch-images
          # https://github.com/docker/metadata-action#annotations
          DOCKER_METADATA_ANNOTATIONS_LEVELS: manifest,index
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        # if: ${{ secrets.DOCKERHUB_USERNAME != '' && secrets.DOCKERHUB_TOKEN != '' }} # does not work: Unrecognized named-value: 'secrets' - https://www.cloudtruth.com/blog/skipping-jobs-in-github-actions-when-secrets-are-unavailable-securely-inject-configuration-secrets-into-github
        if: github.event_name != 'pull_request' # don't try to login since PRs don't have access to secrets and need to set them in their fork
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      - name: Login to GitHub Container Registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }} # actor is user that opened PR, was repository_owner before
          password: ${{ secrets.GITHUB_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 push
        uses: docker/build-push-action@v6
        if: ${{ env.IMAGE_TAG != '' }}
        with:
          context: .
          # push: ${{ github.event_name != 'pull_request' }}
          push: ${{ secrets.DOCKERHUB_USERNAME != '' }} # here we can access secrets
          # TODO speed up by building in parallel? https://docs.docker.com/build/ci/github-actions/multi-platform/#distribute-build-across-multiple-runners
          platforms: linux/amd64,linux/arm64
          build-args: |
            COMMIT=${{ github.sha }}
            BRANCH=${{ env.BRANCH }}
            NOW=${{ env.NOW }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          annotations: ${{ steps.meta.outputs.annotations }}
          # tags: |
          #   ${{ secrets.DOCKERHUB_USERNAME }}/free-games-claimer:${{env.IMAGE_TAG}}
          #   ghcr.io/${{ github.actor }}/free-games-claimer:${{env.IMAGE_TAG}}
          cache-from: type=gha
          cache-to: type=gha,mode=max