ansible/roles/application-install/tasks/custom_role.yml

---
# Caller fills application_custom_role variable with actual role name.
- name: "Execute custom role {{ application_custom_role }} {{ phase }} Helm install."
  include_role:
    name: "{{ application_custom_role }}"
  when:
    - application_custom_role is defined
    - application_custom_role is not none