Avoid Docker Hub login on PR builds

.github/workflows/docker-publish.yml

@@ -25,12 +25,14 @@ jobs:
         uses: docker/setup-buildx-action@v3
 
       - name: Log in to Docker Hub
+        if: github.event_name != 'pull_request'
         uses: docker/login-action@v3
         with:
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}
 
       - name: Extract metadata for Backend
+        if: github.event_name != 'pull_request'
         id: meta-backend
         uses: docker/metadata-action@v5
         with:
@@ -43,11 +45,20 @@ jobs:
             type=semver,pattern={{major}}
             type=sha,prefix=
 
-      - name: Build and push Backend
+      - name: Build Backend image for PR
+        if: github.event_name == 'pull_request'
         uses: docker/build-push-action@v5
         with:
           context: ./backend
-          push: ${{ github.event_name != 'pull_request' }}
+          push: false
+          tags: flclouds-backend:pr-${{ github.event.pull_request.number }}
+
+      - name: Build and push Backend
+        if: github.event_name != 'pull_request'
+        uses: docker/build-push-action@v5
+        with:
+          context: ./backend
+          push: true
           tags: ${{ steps.meta-backend.outputs.tags }}
           labels: ${{ steps.meta-backend.outputs.labels }}
 
@@ -62,12 +73,14 @@ jobs:
         uses: docker/setup-buildx-action@v3
 
       - name: Log in to Docker Hub
+        if: github.event_name != 'pull_request'
         uses: docker/login-action@v3
         with:
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}
 
       - name: Extract metadata for Frontend
+        if: github.event_name != 'pull_request'
         id: meta-frontend
         uses: docker/metadata-action@v5
         with:
@@ -80,10 +93,19 @@ jobs:
             type=semver,pattern={{major}}
             type=sha,prefix=
 
-      - name: Build and push Frontend
+      - name: Build Frontend image for PR
+        if: github.event_name == 'pull_request'
         uses: docker/build-push-action@v5
         with:
           context: ./frontend
-          push: ${{ github.event_name != 'pull_request' }}
+          push: false
+          tags: flclouds-frontend:pr-${{ github.event.pull_request.number }}
+
+      - name: Build and push Frontend
+        if: github.event_name != 'pull_request'
+        uses: docker/build-push-action@v5
+        with:
+          context: ./frontend
+          push: true
           tags: ${{ steps.meta-frontend.outputs.tags }}
           labels: ${{ steps.meta-frontend.outputs.labels }}