build-publish-image-gcr.yml

---
name: Build and Publish Image Workflow

on:
    workflow_call:
        secrets:
            WORKLOAD_ID_PROVIDER:
                required: true
            SERVICE_ACCOUNT:
                required: true
        inputs:
            GCP_PROJECT:
                required: true
                type: string
            VERSION_FILE_PATH:
                required: true
                type: string
            IMAGE_NAME:
                required: true
                type: string
            DOCKER_PATH_CONTEXT:
                required: true
                type: string
            DOCKER_FILE:
                required: false
                type: string
        outputs:
            version_number:
                value: ${{ jobs.build.outputs.version_number }}

jobs:
    build-publish-image:
        runs-on: ubuntu-latest

        permissions:
            contents: read
            id-token: write

        steps:
            - uses: actions/checkout@v3
            # Get version number from version file and store this
            - name: Get Version Number
              id: vars
              shell: bash
              run: |
                  echo "version_number=$(cat ${{ inputs.VERSION_FILE_PATH }})" >> $GITHUB_OUTPUT
            # Set-up Docker Buildx
            - name: Set up Docker Buildx
              id: setup_buildx
              uses: docker/setup-buildx-action@v2
            - name: Authenticate to Google Cloud
              id: gcloud_auth
              uses: google-github-actions/auth@v0
              with:
                  workload_identity_provider: ${{ secrets.WORKLOAD_ID_PROVIDER }}
                  service_account: ${{ secrets.SERVICE_ACCOUNT }}
                  project_id: ${{ inputs.GCP_PROJECT }}
                  token_format: access_token
            - name: Login to GCR
              id: login_to_gcr
              uses: docker/login-action@v2
              with:
                  registry: gcr.io
                  username: oauth2accesstoken
                  password: ${{ steps.gcloud_auth.outputs.access_token }}
            # build docker metadata
            - name: Docker meta
              id: docker_meta
              uses: docker/metadata-action@v4
              with:
                  images: |
                      gcr.io/${{ inputs.GCP_PROJECT }}/${{ inputs.IMAGE_NAME }}
                  tags: |
                      latest
                      type=ref,event=branch
                      type=ref,event=pr
                      ${{ steps.vars.outputs.version_number }}
            # build and push container
            - name: Build and push container
              id: build_push_container
              uses: docker/build-push-action@v3
              with:
                  context: ${{ inputs.DOCKER_PATH_CONTEXT }}
                  file: ${{ inputs.DOCKER_FILE }}
                  push: true
                  tags: ${{ steps.docker_meta.outputs.tags }}
                  cache-from: type=gha
                  cache-to: type=gha,mode=max

        outputs:
            version_number: ${{ steps.vars.outputs.version_number }}