.prepare.gitlab-ci.yml

stages:
  - build

build_ci_runner_image:
  stage: build
  image: docker
  tags:
    - dind
  script:
    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
    - |
      if docker pull $CI_REGISTRY_IMAGE/ci-build-runner:$CI_COMMIT_REF_SLUG; then
        docker build --cache-from $CI_REGISTRY_IMAGE/ci-build-runner:$CI_COMMIT_REF_SLUG --tag $CI_REGISTRY_IMAGE/ci-build-runner:$CI_COMMIT_REF_SLUG docker/ci-runner
      else
        docker pull $CI_REGISTRY_IMAGE/ci-build-runner:latest || true
        docker build --cache-from $CI_REGISTRY_IMAGE/ci-build-runner:latest --tag $CI_REGISTRY_IMAGE/ci-build-runner:$CI_COMMIT_REF_SLUG docker/ci-runner
      fi
    - docker push $CI_REGISTRY_IMAGE/ci-build-runner:$CI_COMMIT_REF_SLUG  # push the image
    - |
      if [[ "$CI_COMMIT_BRANCH" == "$CI_DEFAULT_BRANCH" ]]; then
        docker image tag $CI_REGISTRY_IMAGE/ci-build-runner:$CI_COMMIT_REF_SLUG $CI_REGISTRY_IMAGE/ci-build-runner:latest
        docker push $CI_REGISTRY_IMAGE/ci-build-runner:latest
      fi