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

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