Issue 1389 - Discourse: Don`t run queries for site settings if the correct value is already set

modules/discourse/manifests/sitesetting.pp

 define discourse::sitesetting(
   $setting = $title,
   $value = undef,
   $type = 1,
   $ensure = 'present'
 ) {
   # Attempt some escaping
   $escaped_value = regsubst($value, '[\'\\]', '\\\1', 'G')
   $escaped_setting = regsubst($setting, '[\'\\]', '\\\1', 'G')
   $escaped_type = regsubst($type, '\D', '', 'G')
 
   case $ensure {
     default: {
       err("unknown ensure value ${ensure}")
     }
     present: {
       # This is apparently how you do a conditional INSERT in PostgreSQL - sorry
       $update_sql = "UPDATE site_settings SET value = '$escaped_value', data_type = $escaped_type WHERE name = '$escaped_setting' RETURNING 1"
       $columns = "name, data_type, value, created_at, updated_at"
       $values = "SELECT '$escaped_setting', $escaped_type, '$escaped_value', CURRENT_TIMESTAMP, CURRENT_TIMESTAMP"
 
       postgresql_psql {"WITH upd AS ($update_sql) INSERT INTO site_settings ($columns) $values WHERE NOT EXISTS (SELECT * FROM upd)":
         db => 'discourse',
         psql_user => 'discourse',
-        notify => Service['discourse']
+        notify => Service['discourse'],
+        unless => "SELECT 1 FROM site_settings WHERE name = '$escaped_setting' AND value = '$escaped_value' AND data_type = $escaped_type",
       }
     }
     absent: {
       postgresql_psql {"DELETE FROM site_settings WHERE name = '$escaped_setting'":
         db => 'discourse',
         psql_user => 'discourse',
-        notify => Service['discourse']
+        notify => Service['discourse'],
+        unless => "SELECT 1 WHERE NOT EXISTS (SELECT 1 FROM site_settings WHERE name = '$escaped_setting')",
       }
     }
   }
 }