ci: publish app images to ghcr on push

Author: ppiova

.github/workflows/publish.yml

@@ -0,0 +1,52 @@
+name: Publish images
+
+on:
+  push:
+    branches: [main]
+    tags: ["v*"]
+  workflow_dispatch:
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    strategy:
+      matrix:
+        include:
+          - image: compose-api
+            context: 04-compose/app
+          - image: blazor-chat
+            context: 05-blazor-chat
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository }}/${{ matrix.image }}
+          tags: |
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=sha,format=short
+            type=semver,pattern={{version}}
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: ${{ matrix.context }}
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max