build: split jobs to fix image tagging

.gitlab-ci.yml

@@ -49,14 +49,15 @@ stages:
     - mkdir ${HOME}/.docker
     - echo "${DOCKER_SECRET}" | base64 -d > ${HOME}/.docker/config.json
     - docker info
-
+  script:
+    - docker build -t $IMAGE_TAG .
+    - docker push $IMAGE_TAG
   after_script:
     - rm -rfv ${HOME}/.docker
 
   variables: &vars-docker
     DOCKER_DRIVER: overlay2
     DOCKER_HOST: tcp://localhost:2375
-    IMAGE_TAG: ssube/salty-dog:${CI_COMMIT_TAG:-${CI_COMMIT_REF_SLUG}}
 
 .build-node: &build-node
   image: apextoaster/node:11.15
@@ -98,15 +99,29 @@ build-node:
       - node_modules
       - out/cache
 
-build-image:
+build-image-branch:
   <<: [*build-docker]
   stage: image
+  except:
+    - tags
 
   dependencies:
     - build-node
-  script:
-    - docker build -t $IMAGE_TAG .
-    - docker push $IMAGE_TAG
+  variables:
+    <<: [*vars-docker]
+    IMAGE_TAG: "ssube/salty-dog:${CI_COMMIT_REF_SLUG}"
+
+build-image-tag:
+  <<: [*build-docker]
+  stage: image
+  only:
+    - tags
+
+  dependencies:
+    - build-node
+  variables:
+    <<: [*vars-docker]
+    IMAGE_TAG: "ssube/salty-dog:${CI_COMMIT_TAG}"
 
 # publish jobs
 publish-npm: