.gitlab-ci.yml

stages:
  - build
  - push

image: docker:dind

before_script:
  - echo $CI_JOB_TOKEN | docker login -u gitlab-ci-token --password-stdin $CI_REGISTRY

services:
  - name: docker:dind
    alias: docker
    command: ['--tls=false']

variables:
  DOCKER_DRIVER: overlay2
  DOCKER_HOST: tcp://docker:2375/
  DOCKER_TLS_CERTDIR: ''

Build:
  stage: build
  except:
    variables:
      - $DOCKER_NO_CACHE
  script:
    - docker pull $CI_REGISTRY_IMAGE:latest || true
    - docker build --cache-from $CI_REGISTRY_IMAGE:latest --tag $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA .
    - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA

Push latest:
  variables:
    GIT_STRATEGY: none
  stage: push
  only:
    - master
  script:
    - docker pull $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
    - docker tag $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA $CI_REGISTRY_IMAGE:latest
    - docker push $CI_REGISTRY_IMAGE:latest

Push tag:
  variables:
    GIT_STRATEGY: none
  stage: push
  only:
    - tags
  script:
    - docker pull $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
    - docker tag $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_NAME
    - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_NAME