docker-build-dry-run:
  image: docker:latest
  stage: build-docker
  services:
  - docker:dind
  script:
  - |
    if [[ "$CI_COMMIT_BRANCH" == "$CI_DEFAULT_BRANCH" ]]; then
      tag=""
      echo "Running on default branch '$CI_DEFAULT_BRANCH': tag = 'latest'"
    else
      tag=":$CI_COMMIT_REF_SLUG"
      echo "Running on branch '$CI_COMMIT_BRANCH': tag = $tag"
    fi
  - docker build --pull -t "$CI_REGISTRY_IMAGE${tag}" .
  only:
  - merge_requests