自动化gitlab构建模板，曲线使用缓存创建项目镜像

Docker.gitlab-ci.yml

# 0. 项目中包含Dockerfile
# 1. 设置，指定项目ci模板，如果模板放在公共项目，可以不侵入项目源码
# 2. 设置，配置对应环境变量，公用环境变量设置到项目组，使用gitlab内置变量，比如项目名变量等重写本配置，可能会更加方便
#   - CI_REGISTRY_IMAGE registry.example.com/xxxxxx/yyyyy
#   - REGISTRY  registry.example.com
#   - REGISTRY_USER  uuu
#   - REGISTRY_PASSWORD ppp

.build:
  image: docker:latest
  stage: build
  variables:
    DOCKER_HOST: tcp://docker:2375
    DOCKER_TLS_CERTDIR: ""
  services:
    - name: docker:dind
      alias: docker
      command: [ '--tls=false' ]
  before_script:
    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
  after_script:
    - echo "build tag[$CI_REGISTRY_IMAGE:$CI_REGISTRY_TAG] from branch[$CI_COMMIT_BRANCH]"
    - docker logout $CI_REGISTRY

build-dev:
  extends: .build
  variables:
    CI_REGISTRY_TAG: $CI_COMMIT_REF_NAME # 保留到分支版本
  script:
    - docker pull $CI_REGISTRY_IMAGE:$CI_REGISTRY_TAG || echo "pull failed"
    - docker build --cache-from $CI_REGISTRY_IMAGE:$CI_REGISTRY_TAG -t $CI_REGISTRY_IMAGE:$CI_REGISTRY_TAG .
    - docker push -a $CI_REGISTRY_IMAGE
  rules:
    - if: $CI_REGISTRY_IMAGE && $CI_COMMIT_BRANCH =~ /dev|test|staging/
      exists:
        - Dockerfile

build-release:
  extends: .build
  variables:
    CI_REGISTRY_TAG: $CI_COMMIT_SHA # 主分支保留到版本号
  script:
    # 主分支提交到 latest
    - docker pull $CI_REGISTRY_IMAGE:latest || echo "pull failed"
    - docker build --cache-from $CI_REGISTRY_IMAGE:latest -t $CI_REGISTRY_IMAGE:$CI_REGISTRY_TAG -t $CI_REGISTRY_IMAGE:latest .
    - docker push -a $CI_REGISTRY_IMAGE
  rules:
    - if: $CI_REGISTRY_IMAGE && $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH
      exists:
        - Dockerfile