sub-build-docker-image.yml

name: Build docker image

on:
  workflow_call:
    inputs:
      app_name:
        required: true
        type: string
      dockerfile_path:
        required: true
        type: string
      dockerfile_target:
        required: true
        type: string
      registry:
        required: true
        type: string
      environment:
        required: true
        type: string
    outputs:
      image_digest:
        description: The image digest to be used on a caller workflow
        value: ${{ jobs.build.outputs.image_digest }}

permissions: read-all

jobs:
  build:
    name: Build images
    timeout-minutes: 15
    runs-on: ubuntu-latest
    outputs:
      image_digest: ${{ steps.docker_build.outputs.digest }}
    permissions:
      contents: read
      id-token: write
    steps:
      - uses: actions/checkout@v4.1.7
        with:
          persist-credentials: false

      - name: Inject slug/short variables
        uses: rlespinasse/github-slug-action@v4.5.0
        with:
          short-length: 7

      # Automatic tag management and OCI Image Format Specification for labels
      - name: Docker meta
        id: meta
        uses: docker/metadata-action@v5.5.1
        with:
          # list of Docker images to use as base name for tags
          images: |
            ${{ inputs.registry }}/${{ inputs.app_name }}
          # generate Docker tags based on the following events/attributes
          tags: |
            type=schedule
            # semver and ref,tag automatically add a "latest" tag, but only on stable releases
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=semver,pattern={{major}}
            type=ref,event=tag
            type=ref,event=branch
            type=ref,event=pr
            type=sha
            # edge is the latest commit on the default branch.
            type=edge,enable={{is_default_branch}}

      # Setup Docker Buildx to allow use of docker cache layers from GH
      - name: Set up Docker Buildx
        id: buildx
        uses: docker/setup-buildx-action@v3.4.0

      - name: Authenticate to Google Cloud
        id: auth
        uses: google-github-actions/auth@v2.1.3
        with:
          workload_identity_provider: '${{ vars.GCP_WIF }}'
          service_account: '${{ vars.GCP_ARTIFACTS_SA }}'
          token_format: access_token
          # Some builds might take over an hour, and Google's default lifetime duration for
          # an access token is 1 hour (3600s). We increase this to 3 hours (10800s)
          # as some builds take over an hour.
          access_token_lifetime: 10800s

      - name: Login to Google Artifact Registry
        uses: docker/login-action@v3.2.0
        with:
          registry: us-docker.pkg.dev
          username: oauth2accesstoken
          password: ${{ steps.auth.outputs.access_token }}

      # Build and push image to Google Artifact Registry, and possibly DockerHub
      - name: Build & push
        id: docker_build
        uses: docker/build-push-action@v6.3.0
        with:
          target: ${{ inputs.dockerfile_target }}
          context: .
          file: ${{ inputs.dockerfile_path }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          push: true
          # To improve build speeds, for each branch we push an additional image to the registry,
          # to be used as the caching layer, using the `max` caching mode.
          #
          # We use multiple cache sources to confirm a cache hit, starting from a per-branch cache,
          # and if there's no hit, then continue with the `main` branch. When changes are added to a PR,
          # they are usually smaller than the diff between the PR and `main` branch. So this provides the
          # best performance.
          #
          # The caches are tried in top-down order, the first available cache is used:
          # https://github.com/moby/moby/pull/26839#issuecomment-277383550
          cache-from: |
            type=registry,ref=${{ inputs.registry }}/${{ inputs.app_name }}:${{ env.GITHUB_REF_SLUG_URL }}-cache
            type=registry,ref=${{ inputs.registry }}/${{ inputs.app_name }}:${{ github.event.repository.default_branch }}-cache
          cache-to: |
            type=registry,ref=${{ inputs.registry }}/${{ inputs.app_name }}:${{ env.GITHUB_REF_SLUG_URL }}-cache,mode=min