pipeline:

  docker:
    image: plugins/docker
    repo: bunix42/google-cloud-sdk
    build_args:
      - BASE_IMAGE=google/cloud-sdk:${VERSION}
      - KUBECTL_VERSION=${KUBECTL_VERSION}
    tags:
     - ${VERSION}_kubectl-${KUBECTL_VERSION}
    secrets: [ docker_username, docker_password ]
    when:
      branch: master

matrix:
  VERSION:
    - 193.0.0-alpine
  KUBECTL_VERSION:
    - v1.9.10
    - v1.10.7
    - v1.11.2