Update docker-publish.yml

.github/workflows/docker-publish.yml

@@ -35,7 +35,11 @@ jobs:
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@f95db51fddba0c2d1ec667646a06c2ce06100226 # v3.0.0
-
+
+      - name: Install skopeo and jq
+        run: |
+          sudo apt-get update && sudo apt-get install -y skopeo jq
+          
       - name: Log into registry ${{ env.REGISTRY }}
         if: github.event_name != 'pull_request'
         uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # v3.0.0
@@ -56,11 +60,14 @@ jobs:
           docker-compose build
           DOCKER_IMAGE=$(docker-compose images --format "{{.Repository}}:{{.Tag}}")
           docker-compose push
+          DIGEST=$(skopeo inspect docker://${DOCKER_IMAGE} | jq -r '.Digest')
+          echo "DIGEST=${DIGEST}" >> $GITHUB_ENV
         env:
           DOCKER_BUILDKIT: 1
 
       - name: Sign the published Docker image
         if: ${{ github.event_name != 'pull_request' }}
         env:
           TAGS: ${{ steps.meta.outputs.tags }}
-        run:  echo "${TAGS}" | xargs -I {} cosign sign --yes {}
+          DIGEST: ${{ env.DIGEST }}
+        run:  echo "${TAGS}" | xargs -I {} cosign sign --yes {}@${DIGEST}