.gitlab-ci.yml

# Build a Docker image for branches and tags

docker-build:
  image: docker:latest
  stage: build
  services:
    - docker:dind
  before_script:
    - docker login -u "$CI_REGISTRY_USER" -p "$CI_REGISTRY_PASSWORD" $CI_REGISTRY
  # Tagging images in following priority:
  # * Commit tag name
  # * latest if on master
  # * Commit reference if on different branch
  script:
    - |
      if [ -n "$CI_COMMIT_TAG" ]; then
        tag="$CI_COMMIT_TAG"
      elif [[ "$CI_COMMIT_BRANCH" == "$CI_DEFAULT_BRANCH" ]]; then
        tag="latest"
      else
        tag="$CI_COMMIT_REF_SLUG"
      fi

      echo "Running on branch '$CI_COMMIT_BRANCH'"
      echo "Tagging as '$tag'"
    - docker build --pull -t "$CI_REGISTRY_IMAGE:${tag}" .
    - docker push "$CI_REGISTRY_IMAGE:${tag}"