setup/roles/signal/tasks/main.yml

- name: Get Signal APT key
  become: true
  get_url:
    url: https://updates.signal.org/desktop/apt/keys.asc
    dest: /etc/apt/trusted.gpg.d/signal.asc
- name: Install Signal APT repository
  become: true
  apt_repository:
    repo: "deb [arch=amd64 signed-by=/etc/apt/trusted.gpg.d/signal.asc] https://updates.signal.org/desktop/apt xenial main"
  register: apt_repository
- name: Update APT cache
  become: true
  apt:
    update_cache: true
  when: apt_repository.changed
- name: Install Signal
  become: true
  apt:
    name: signal-desktop