image: docker:18-git

stages:
  - build

before_script:
  - export VERSION=$(cat VERSION)
  - export CI_REGISTRY=${CI_REGISTRY:-hub.docker.com}
  - export CI_REGISTRY_USER=${CI_REGISTRY_USER:-gitlab-ci-token}
  - export CI_REGISTRY_PASSWORD=${CI_REGISTRY_PASSWORD:-${CI_JOB_TOKEN}}
  - export DOCKER_IMAGE=${DOCKER_IMAGE:-${CI_REGISTRY}/${CI_PROJECT_PATH}}
  - |
    if [ "${DOCKER_IMAGE}" = "/" ]; then
      export DOCKER_IMAGE=sameersbn/gitlab
    fi

docker:build:
  stage: build
  only:
    - master
  script:
    - docker login -u ${CI_REGISTRY_USER} -p ${CI_REGISTRY_PASSWORD} ${CI_REGISTRY}
    - docker build
      --pull
      --cache-from=${DOCKER_IMAGE}
      --build-arg=VCS_REF=$(git rev-parse --short HEAD)
      --build-arg=BUILD_DATE="$(date +"%Y-%m-%d %H:%M:%S%:z")"
      --tag ${DOCKER_IMAGE} .
    - docker push ${DOCKER_IMAGE}

docker:build:branches:
  stage: build
  only:
    - branches
  except:
    - master
  script:
    - docker login -u ${CI_REGISTRY_USER} -p ${CI_REGISTRY_PASSWORD} ${CI_REGISTRY}
    - docker build
      --pull
      --cache-from=${DOCKER_IMAGE}:${CI_COMMIT_REF_SLUG}
      --build-arg=VCS_REF=$(git rev-parse --short HEAD)
      --build-arg=BUILD_DATE="$(date +"%Y-%m-%d %H:%M:%S%:z")"
      --tag ${DOCKER_IMAGE}:${CI_COMMIT_REF_SLUG} .
    - docker push ${DOCKER_IMAGE}:${CI_COMMIT_REF_SLUG}

docker:build:release:
  stage: build
  only:
    - tags
  script:
    - docker login -u ${CI_REGISTRY_USER} -p ${CI_REGISTRY_PASSWORD} ${CI_REGISTRY}
    - docker build
      --pull
      --cache-from=${DOCKER_IMAGE}:${VERSION}
      --build-arg=VCS_REF=$(git rev-parse --short HEAD)
      --build-arg=BUILD_DATE="$(date +"%Y-%m-%d %H:%M:%S%:z")"
      --tag ${DOCKER_IMAGE}:${VERSION} .
    - docker push ${DOCKER_IMAGE}:${VERSION}