ci(gitlab-ci): replace manual frontend container build

check if image already exists in the registry and build if not; also rebuild on manual run

.gitlab-ci.yml

@@ -77,28 +77,32 @@ setup:dynamic:
   rules:
     - when: always
 
-setup:containers:frontend: &containers-frontend
+setup:containers:frontend:
   stage: setup
   needs:
     - setup:dynamic
   image: ${IMAGE_BUILDER}
   script:
     - FRONTEND_IMAGE_VERSION=`cat frontend-image-version`
-    - buildah bud -t frontend/${CI_COMMIT_REF_SLUG}:${FRONTEND_IMAGE_VERSION} --build-arg PROJECT_DIR=${CI_PROJECT_DIR} --volume ${CI_PROJECT_DIR}:/tmp/${CI_PROJECT_DIR} --file docker/frontend/Dockerfile
-    - buildah push --creds "${CI_REGISTRY_USER}:${CI_JOB_TOKEN}" frontend/${CI_COMMIT_REF_SLUG}:${FRONTEND_IMAGE_VERSION} ${CI_REGISTRY_IMAGE}/frontend/${CI_COMMIT_REF_SLUG}:${FRONTEND_IMAGE_VERSION}
-  rules:
-    - changes:
-        paths:
-          - docker/frontend/Dockerfile
-          - package.json
-          - package-lock.json
-          - webpack.config.js
-  interruptible: false
-setup:containers:frontend:manual:
-  <<: *containers-frontend
+    - IMAGE_TAG=frontend/${CI_COMMIT_REF_SLUG}:${FRONTEND_IMAGE_VERSION}
+    - REGISTRY_DESTINATION=${CI_REGISTRY_IMAGE}/frontend/${CI_COMMIT_REF_SLUG}:${FRONTEND_IMAGE_VERSION}
+    - IMAGE_EXISTS=`curl "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/registry/repositories?tags=true" | grep \""${REGISTRY_DESTINATION}"\"`
+    - ${FORCE_REBUILD_IMAGE} && echo "Force rebuilding container."
+    - >
+      if [ ${IMAGE_EXISTS} -a ! ${FORCE_REBUILD_IMAGE} ]; then
+        echo "Image ${IMAGE_TAG} already exists in the container registry. Skipping build."
+      else
+        echo "Building image..."
+        buildah bud -t ${IMAGE_TAG} --build-arg PROJECT_DIR=${CI_PROJECT_DIR} --volume ${CI_PROJECT_DIR}:/tmp/${CI_PROJECT_DIR} --file docker/frontend/Dockerfile
+        buildah push --creds "${CI_REGISTRY_USER}:${CI_JOB_TOKEN}" ${IMAGE_TAG} ${REGISTRY_DESTINATION}
   rules:
+    - when: always
+      variables:
+        FORCE_REBUILD_IMAGE: false
     - when: manual
-  allow_failure: true
+      variables:
+        FORCE_REBUILD_IMAGE: true
+  interruptible: false
 
 setup:containers:backend: &containers-backend
   stage: setup