matrix-docker-ansible-deploy/roles/matrix-base/tasks/self_check_dns_srv.yml

---

# This requires the dnspython library which is usually unavailable.
- name: Check DNS SRV record for {{ dns_srv_record_check.service_and_protocol }} on {{ dns_srv_record_check.domain }} using Ansible dig lookup
  set_fact:
    lookup_dig_srv: "{{ lookup('dig', (dns_srv_record_check.service_and_protocol + '.' + dns_srv_record_check.domain + '/SRV'), 'flat=0', wantlist=False) }}"
  register: result_lookup_dig_srv
  ignore_errors: true

- name: Fail if DNS SRV check via Ansible dig lookup failed for non-dependency reason
  fail:
    msg: "DNS SRV record check via Ansible dig lookup plugin (which uses the dnspython package) failed. Error is: {{ result_lookup_dig_srv.msg }}"
  when: "result_lookup_dig_srv.failed and 'dnspython' not in result_lookup_dig_srv.msg"

# Fallback to using the dig CLI tool if dnspython was unavailable.
- name: Check DNS SRV record for {{ dns_srv_record_check.service_and_protocol }} on {{ dns_srv_record_check.domain }} using dig CLI tool
  shell:
    cmd: "dig -t srv {{ (dns_srv_record_check.service_and_protocol + '.' + dns_srv_record_check.domain)|quote }}"
  register: result_cli_dig_srv
  changed_when: false
  ignore_errors: true
  when: "lookup_dig_srv is not defined"

- name: Fail if dig CLI used and failed
  fail:
    msg: >-
      Failed performing DNS SRV record check.
      You neither have the `dnspython` Python package, nor the `dig` program installed locally.
      You need to install one of those, so we could perform a DNS SRV record check.
      Full error from trying to run `dig`: {{ result_cli_dig_srv }}
  when: "lookup_dig_srv is not defined and result_cli_dig_srv.stderr != ''"

# Some DNS servers may respond with '' (stands for "No Answer").
# Most usually, a missing record would yield a 'NXDOMAIN' response.
# In any case, we consider any non-mapping response to mean "missing record".
- name: Fail if DNS SRV record missing (Ansible dig lookup)
  fail:
    msg: >-
      It appears the DNS SRV record for {{ dns_srv_record_check.service_and_protocol }} on {{ dns_srv_record_check.domain }} is not set up correctly (the record is missing).
      See the 'Configuring DNS' documentation for this playbook.
  when: "lookup_dig_srv is defined and lookup_dig_srv is not mapping"

- name: Fail if DNS SRV record incorrect (Ansible dig lookup)
  fail:
    msg: >-
      It appears the DNS SRV record for {{ dns_srv_record_check.service_and_protocol }} on {{ dns_srv_record_check.domain }} is not set up correctly.
      Expected it to point to `{{ dns_srv_record_check.expected_target }}` (port {{ dns_srv_record_check.expected_port }}).
      Found it pointing to `{{ lookup_dig_srv.target }}` (port {{ lookup_dig_srv.port }}).
      See the 'Configuring DNS' documentation for this playbook.
  when: "lookup_dig_srv is defined and (lookup_dig_srv.target != dns_srv_record_check.expected_target or lookup_dig_srv.port != dns_srv_record_check.expected_port)"

# 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 missing or incorrect (dig CLI tool)
  fail:
    msg: >-
      It appears the DNS SRV record for {{ dns_srv_record_check.service_and_protocol }} on {{ dns_srv_record_check.domain }} is not set up correctly.
      Expected it to point to `{{ dns_srv_record_check.expected_target }}` (port {{ dns_srv_record_check.expected_port }}).
      See the 'Configuring DNS' documentation for this playbook.
      Full response from the `dig` lookup was: {{ result_cli_dig_srv }}
  when: "lookup_dig_srv is not defined and (dns_srv_record_check.expected_port|string + ' ' + dns_srv_record_check.expected_target) not in result_cli_dig_srv.stdout"

- name: Report correct DNS SRV record
  debug:
    msg: >-
      The DNS SRV record for `{{ dns_srv_record_check.service_and_protocol }}` on `{{ dns_srv_record_check.domain }}`
      points to `{{ dns_srv_record_check.expected_target }}` (port {{ dns_srv_record_check.expected_port }}), as expected.