---
- name: add repository key
  copy:
    src: docker-com.gpg
    dest: /etc/apt/trusted.gpg.d/docker.gpg
  register: apt_repo_docker_com_key

- name: add repository entry
  copy:
    content: |
      deb https://download.docker.com/linux/{{ ansible_distribution | lower }} {{ ansible_distribution_release }} stable
    dest: /etc/apt/sources.list.d/docker.list
  register: apt_repo_docker_com_key

- name: update apt cache
  when: apt_repo_docker_com_key is changed or
        apt_repo_docker_com_sources is changed
  apt:
    update_cache: yes