Update push docker container to support container registry

Also simplify the existing workflow by replacing shell code with actions

ci/docker-publish.yml

@@ -2,20 +2,22 @@ name: Docker
 
 on:
   push:
-    # Publish `$default-branch` as Docker `latest` image.
-    branches:
-      - $default-branch
-
+    branches: [ $default-branch ]
     # Publish `v1.2.3` tags as releases.
-    tags:
-      - v*
+    tags: [ 'v*.*.*' ]
+    pull_request_target:
+      branches: [ $default-branch ]
 
   # Run tests for any PRs.
   pull_request:
 
 env:
-  # TODO: Change variable to your image's name.
-  IMAGE_NAME: image
+  # TODO: Creates container named ACCOUNT/REPO
+  #       Append /IMAGE-NAME to create a container named ACCOUNT/REPO/IMAGE-NAME
+  IMAGE_NAME: ${{ github.repository }}
+
+  # Registry. Use docker.io for DockerHub
+  REGISTRY: ghcr.io
 
 jobs:
   # Run tests.
@@ -49,32 +51,31 @@ jobs:
       packages: write
 
     steps:
-      - uses: actions/checkout@v2
+      - name: Checkout repository
+        uses: actions/checkout@v2
 
-      - name: Build image
-        run: docker build . --file Dockerfile --tag $IMAGE_NAME
+      - name: Log into registry ${{ env.REGISTRY }}
+        uses: docker/login-action@v1
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Log into registry
-        run: echo "${{ secrets.GITHUB_TOKEN }}" | docker login docker.pkg.github.com -u ${{ github.actor }} --password-stdin
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+              type=ref,event=branch
+              type=ref,event=pr
+              type=semver,pattern={{version}}
 
-      - name: Push image
-        run: |
-          IMAGE_ID=docker.pkg.github.com/${{ github.repository }}/$IMAGE_NAME
-
-          # Change all uppercase to lowercase
-          IMAGE_ID=$(echo $IMAGE_ID | tr '[A-Z]' '[a-z]')
-
-          # Strip git ref prefix from version
-          VERSION=$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')
-
-          # Strip "v" prefix from tag name
-          [[ "${{ github.ref }}" == "refs/tags/"* ]] && VERSION=$(echo $VERSION | sed -e 's/^v//')
-
-          # Use Docker `latest` tag convention
-          [ "$VERSION" == "$default-branch" ] && VERSION=latest
-
-          echo IMAGE_ID=$IMAGE_ID
-          echo VERSION=$VERSION
-
-          docker tag $IMAGE_NAME $IMAGE_ID:$VERSION
-          docker push $IMAGE_ID:$VERSION
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          # Don't push on pull requests
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}