- name: Check if Zuul merger containers are running
  # It is possible they are stopped due to some external circumstance.
  # NOTE: docker-compose ps -q reports exited containers unlike docker ps -q
  command:
    cmd: docker-compose ps -q
    chdir: /etc/zuul-merger
  become: true
  become_user: root
  register: merger_container_list
- name: Gracefully stop Zuul Merger
  shell:
    cmd: docker-compose exec -T merger zuul-merger stop
    chdir: /etc/zuul-merger
  become: true
  become_user: root
  # Only run the docker exec command if a container is running
  when: merger_container_list.stdout_lines | length > 0
  register: zm_graceful
  failed_when:
    - zm_graceful.rc != 0
    # There is a fun race with docker exec and shutting down the
    # container running the exec. If the container is stopped while
    # the exec is running then the command in the exec effectively gets
    # kill -9'd and the docker exec command rc is 137. Since this
    # should only happen when the container is stopped we proceed with
    # the overall graceful shutdown.
    - zm_graceful.rc != 137
    # If the exec fails because the container is not running we continue.
    - "'No container found' not in zm_graceful.stderr"
- name: Wait for Zuul Merger to stop
  shell:
    cmd: docker-compose ps -q | xargs docker wait
    chdir: /etc/zuul-merger
  become: true
  become_user: root
  when: merger_container_list.stdout_lines | length > 0
- name: Down Zuul Merger containers
  shell:
    cmd: docker-compose down
    chdir: /etc/zuul-merger
  become: true
  become_user: root