matrix-docker-ansible-deploy/roles/matrix-server/tasks/self_check/self_check_dns.yml

---

- name: Check DNS SRV record
  shell:
    cmd: "dig -t srv {{ ('_matrix._tcp.' + hostname_identity + '.')|quote }}"
  register: result_dig_srv
  changed_when: false
  ignore_errors: true

- name: Fail if dig failed
  fail:
    msg: "Failed checking DNS SRV record. You likely don't have the `dig` program installed locally. Full error: {{ result_dig_srv }}"
  when: "result_dig_srv.stderr != ''"

# We expect an answer like this:
# ;; ANSWER SECTION:
# _matrix._tcp.DOMAIN. 10800	IN	SRV	10 0 8448 matrix.DOMAIN.
- name: Fail if DNS SRV record incorrect
  fail:
    msg: "It appears the DNS SRV record for {{ hostname_identity }} is not set up correctly. See the 'Configuring DNS' documentation for this playbook. Full DNS answer was: {{ result_dig_srv.stdout }}"
  when: "('8448 ' + hostname_matrix) not in result_dig_srv.stdout"

- name: Report correct DNS SRV record
  debug:
    msg: "The DNS SRV record for {{ hostname_identity }} points to {{ hostname_matrix }}, as expected"