matrix-docker-ansible-deploy/roles/matrix-etherpad/tasks/validate_config.yml

- name: Fail if required Etherpad settings not defined
  fail:
    msg: >-
      You need to define a required configuration setting (`{{ item }}`) for using Etherpad.
  with_items:
    -
  when: "matrix_etherpad_enabled and vars[item] == ''"