image: docker:git
services:
- docker:dind

stages:
- build
- test
- release

variables:
  TEST_IMAGE: ${CI_REGISTRY_IMAGE}:$CI_BUILD_REF_NAME
  RELEASE_IMAGE: ${CI_REGISTRY_IMAGE}:latest

before_script:
  - echo $CI_BUILD_TOKEN | docker login -u gitlab-ci-token --password-stdin ${CI_REGISTRY}

build:
  stage: build
  script:
    - docker build -t $TEST_IMAGE .
    - docker push $TEST_IMAGE

test:
  stage: test
  script:
    - docker run $TEST_IMAGE /test

release:
  stage: release
  script:
    - echo Publishing ${RELEASE_IMAGE}
    - docker pull $TEST_IMAGE
    - docker tag $TEST_IMAGE $RELEASE_IMAGE
    - docker push $RELEASE_IMAGE
  only:
    - master
    - tags