From afda425fab2d64462caec8897c86b2900fbcd42d Mon Sep 17 00:00:00 2001
From: Ben Vincent <ben@unkin.net>
Date: Tue, 3 Sep 2024 22:11:21 +1000
Subject: [PATCH] feat: psql changes on master only

- add fact to detect if a psql host is a slave
- only import users/db/grants on master
---
 modules/libs/lib/facter/psql_is_slave.rb | 11 +++++++++++
 site/profiles/manifests/sql/patroni.pp   | 13 ++++++++-----
 2 files changed, 19 insertions(+), 5 deletions(-)
 create mode 100644 modules/libs/lib/facter/psql_is_slave.rb

diff --git a/modules/libs/lib/facter/psql_is_slave.rb b/modules/libs/lib/facter/psql_is_slave.rb
new file mode 100644
index 0000000..3cb8938
--- /dev/null
+++ b/modules/libs/lib/facter/psql_is_slave.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+Facter.add(:psql_is_slave) do
+  setcode do
+    # Command to check if PostgreSQL is in recovery mode
+    command = 'sudo -iu postgres psql -tAc "select pg_is_in_recovery()"'
+
+    # Execute the command and map the output to a boolean value
+    { 't' => true, 'f' => false }[Facter::Core::Execution.execute(command, on_fail: nil)]
+  end
+end
diff --git a/site/profiles/manifests/sql/patroni.pp b/site/profiles/manifests/sql/patroni.pp
index e53dcc4..45b91c4 100644
--- a/site/profiles/manifests/sql/patroni.pp
+++ b/site/profiles/manifests/sql/patroni.pp
@@ -88,11 +88,14 @@ class profiles::sql::patroni (
 
   }
 
-  # collect exported resources
-  $tag = "${facts['country']}-${facts['region']}-${facts['environment']}"
-  Profiles::Sql::Postgres::Db <<| tag == $tag |>> {}
-  Profiles::Sql::Postgres::User <<| tag == $tag |>> {}
-  Profiles::Sql::Postgres::Grant <<| tag == $tag |>> {}
+  # only apply changes to DBs/Users/Grants on master
+  if ! $facts['psql_is_slave'] {
+    # collect exported resources
+    $tag = "${facts['country']}-${facts['region']}-${facts['environment']}"
+    Profiles::Sql::Postgres::Db <<| tag == $tag |>> {}
+    Profiles::Sql::Postgres::User <<| tag == $tag |>> {}
+    Profiles::Sql::Postgres::Grant <<| tag == $tag |>> {}
+  }
 
   if $postgres_exporter_enabled {
     class { 'prometheus::postgres_exporter':
-- 
2.47.3