hyperlane-monorepo/.github/workflows/docker.yml

name: Push to GCR GitHub Action
on: 
  push:
    branches:
      - '**'
    tags:
      - '**'
  # pull_request:
  #   branches:
  #     - 'main'
jobs:
  check-env:
    runs-on: ubuntu-latest
    # assign output from step to job output
    outputs:
      gcloud-service-key: ${{ steps.gcloud-service-key.outputs.defined }}
    steps:
      - id: gcloud-service-key
        # assign GCLOUD_SERVICE_KEY to env for access in conditional
        env:
          GCLOUD_SERVICE_KEY: ${{ secrets.GCLOUD_SERVICE_KEY }}
        if: "${{ env.GCLOUD_SERVICE_KEY != '' }}"
        # runs if GCLOUD_SERVICE_KEY is defined, so we set the output to true
        run: echo "::set-output name=defined::true"

  build-and-push-to-gcr:
    runs-on: ubuntu-latest

    # uses check-env to determine if secrets.GCLOUD_SERVICE_KEY is defined
    needs: [check-env]
    if: needs.check-env.outputs.gcloud-service-key == 'true'

    steps:
      - uses: actions/checkout@v2
      -
        name: Docker meta
        id: meta
        uses: docker/metadata-action@v3
        with:
          # list of Docker images to use as base name for tags
          images: |
                        gcr.io/clabs-optics/optics-agent
          # generate Docker tags based on the following events/attributes
          tags: |
            type=ref,event=branch
            type=ref,event=pr
            type=sha            
      - 
        name: Login to GCR
        uses: docker/login-action@v1
        with:
          registry: gcr.io
          username: _json_key
          password: ${{ secrets.GCLOUD_SERVICE_KEY }}
      -
        name: Build and push
        uses: docker/build-push-action@v2
        env: 
          DOCKER_BUILDKIT: 1
        with:
          context: ./rust
          file: ./rust/Dockerfile
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}