Simple Gitlab Pipeline (Docker Builder)

.gitlab-ci.yml

stages:
  - build

build:
  stage: build
  image: docker:19.03.12
  services:
    - docker:19.03.12-dind
  variables:
    IMAGE_TAG: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG
  script:
    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
    - docker build -t $IMAGE_TAG .
    - docker push $IMAGE_TAG
    - ([ "${CI_COMMIT_REF_NAME}" == "master" ] && docker build -t $CI_REGISTRY_IMAGE:latest .) || echo "Not latest build"
    - ([ "${CI_COMMIT_REF_NAME}" == "master" ] && docker push $CI_REGISTRY_IMAGE:latest) || echo "Not latest build"