From 0ff6735546fe368698ed43d76e7b6118b199df46 Mon Sep 17 00:00:00 2001 From: Slavi Pantaleev Date: Mon, 28 Jan 2019 09:42:04 +0200 Subject: [PATCH] Fall back to dig for SRV lookup, if no dnspython This is a known/intentional regression since f92c4d5a27d7758fc. The new stance on this is that most people would not have dnspython, but may have the `dig` tool. There's no good reason for not increasing our chances of success by trying both methods (Ansible dig lookup and using the `dig` CLI tool). Fixes #85 (Github issue). --- .../matrix-base/tasks/self_check_dns_srv.yml | 63 +++++++++++++++---- 1 file changed, 51 insertions(+), 12 deletions(-) diff --git a/roles/matrix-base/tasks/self_check_dns_srv.yml b/roles/matrix-base/tasks/self_check_dns_srv.yml index 249b10ee..9300fb65 100644 --- a/roles/matrix-base/tasks/self_check_dns_srv.yml +++ b/roles/matrix-base/tasks/self_check_dns_srv.yml @@ -1,26 +1,65 @@ --- -# This requires the dnspython library and will fail with a friendly error when unavailable. -- name: Check DNS SRV record for {{ dns_srv_record_check.service_and_protocol }} on {{ dns_srv_record_check.domain }} +# 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: - result_dig_srv: "{{ lookup('dig', (dns_srv_record_check.service_and_protocol + '.' + dns_srv_record_check.domain + '/SRV'), 'flat=0', wantlist=False) }}" + 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 record missing +- name: Fail if DNS SRV check via Ansible dig lookup failed for non-dependency reason 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: "result_dig_srv == 'NXDOMAIN'" + 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" -- name: Fail if DNS SRV record incorrect +# 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 != ''" + +- 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 == 'NXDOMAIN'" + +- 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: > + 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 `{{ result_dig_srv.target }}` (port {{ result_dig_srv.port }}). See the 'Configuring DNS' documentation for this playbook. - when: "result_dig_srv.target != dns_srv_record_check.expected_target or result_dig_srv.port != dns_srv_record_check.expected_port" + 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: > + msg: >- The DNS SRV record for `{{ dns_srv_record_check.service_and_protocol }}` on `{{ dns_srv_record_check.domain }}` - points to `{{ result_dig_srv.target }}` (port {{ dns_srv_record_check.expected_port }}), as expected \ No newline at end of file + points to `{{ dns_srv_record_check.expected_target }}` (port {{ dns_srv_record_check.expected_port }}), as expected.