Fix provenance task

.github/workflows/publish.yml

@@ -8,6 +8,9 @@ jobs:
     permissions:
       contents: read
       packages: write
+    outputs:
+      image: ${{ steps.image.outputs.image }}
+      digest: ${{ steps.build.outputs.digest }}
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-java@v3
@@ -18,15 +21,32 @@ jobs:
         run: mvn --batch-mode deploy
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@dc7b9719a96d48369863986a06765841d7ea23f6
       - name: Login to Docker Hub
         uses: docker/login-action@v3
         with:
           username: ${{ secrets.DOCKERHUB_USER }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
-      - name: Build image
-        run: docker build . --file Dockerfile --platform linux/amd64 --tag "andifalk/supply-chain-security:${GITHUB_REF_NAME}"
-      - name: Push image
-        run: docker push "andifalk/supply-chain-security:${GITHUB_REF_NAME}"
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@69f6fc9d46f2f8bf0d5491e4aabe0bb8c6a4678a
+        with:
+          images: andifalk/supply-chain-security
+      - name: Build and push Docker image
+        uses: docker/build-push-action@e551b19e49efd4e98792db7592c17c09b89db8d8
+        id: build
+        with:
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+      - name: Output image
+        id: image
+        run: |
+          # NOTE: Set the image as an output because the `env` context is not
+          # available to the inputs of a reusable workflow call.
+          image_name="andifalk/supply-chain-security"
+          echo "image=$image_name" >> "$GITHUB_OUTPUT"
 
   # This step calls the container workflow to generate provenance and push it to
   # the container registry.
@@ -38,7 +58,8 @@ jobs:
       packages: write # for uploading attestations.
     uses: slsa-framework/slsa-github-generator/.github/workflows/[email protected]
     with:
-      image: "andifalk/supply-chain-security:${GITHUB_REF_NAME}"
+      image: "andifalk/supply-chain-security"
+      digest: ${{ needs.build.outputs.digest }}
       registry-username: andifalk
     secrets:
       registry-password: ${{ secrets.DOCKERHUB_TOKEN }}