👷 rebuild docker image. push to gcr

.github/workflows/container-image.yml

@@ -0,0 +1,65 @@
+name: Docker Image CI
+
+on:
+  workflow_dispatch:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+  TAG: "3.1"
+
+jobs:
+
+  main-root:
+    outputs:
+      is-main: ${{ steps.is-main-root.outputs.test }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Echo a message
+        if: github.ref == 'refs/heads/main' && github.repository == 'commonhaus/pandoc-pdf'
+        id: is-main-root
+        run: echo "test=true" >> "$GITHUB_OUTPUT"
+
+  build:
+    needs: main-root
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Extract metadata (tags, labels) for Docker
+      id: meta
+      uses: docker/metadata-action@v4
+      with:
+        images: ${{ github.repository }}
+        tags: |
+          type=raw,enable=true,priority=200,prefix=,suffix=,value=${{ env.TAG }}
+
+    - name: Log in to the Container registry
+      if: ${{needs.main-root.outputs.is-main}}
+      uses: docker/login-action@9780b0c442fbb1117ed29e0efdff1e18412f7567
+      with:
+        registry: ${{ env.REGISTRY }}
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Build and push Docker image
+      uses: docker/build-push-action@v6.9.0
+      with:
+        context: .
+        push: false
+        tags: ${{ steps.meta.outputs.tags }}
+        labels: ${{ steps.meta.outputs.labels }}
+
+
+    - name: Publish OCI image to GCR
+      if: ${{needs.main-root.outputs.is-main}}
+      id: publish-oci
+      run: |
+        image="${IMAGE_NAME}:${TAG}"
+        docker tag "${image}" "ghcr.io/${image}"
+        docker push "ghcr.io/${image}"