Switch to enabling the managment plugin by default

Over time the managment plugin has become a core part of managing
a rabbit deployment. This includes allowing tools such as nrpe to
be able to query the api and alert for situations such as orphaned
queues.

Change-Id: Icbf760610ce83b9d95f48e99f6607ddf23963c97
Partial-Bug: 1930547

config.yaml

@@ -28,8 +28,10 @@ options:
       to run. Supported modules currently include os, ssh, apache and mysql.
   management_plugin:
     type: boolean
-    default: False
-    description: Enable the management plugin.
+    default: True
+    description: |
+      Enable the management plugin. This only applys to deployments using
+      Focal or later.
   mirroring-queues:
     type: boolean
     default: True

hooks/rabbit_utils.py

@@ -89,6 +89,8 @@ from charmhelpers.core.host import (
     write_file,
     cmp_pkgrevno,
     rsync,
+    lsb_release,
+    CompareHostReleases,
 )
 
 from charmhelpers.contrib.peerstorage import (
@@ -1421,6 +1423,19 @@ def remove_file(path):
         log('{} file does not exist'.format(path), level='DEBUG')
 
 
+def management_plugin_enabled():
+    """Check if management plugin should be enabled.
+
+    :returns: Whether anagement plugin should be enabled
+    :rtype: bool
+    """
+    _release = lsb_release()['DISTRIB_CODENAME'].lower()
+    if CompareHostReleases(_release) < "bionic":
+        return False
+    else:
+        return config('management_plugin') is True
+
+
 def sync_nrpe_files():
     """Sync all NRPE-related files.
 
@@ -1436,7 +1451,7 @@ def sync_nrpe_files():
     if config('queue_thresholds') and config('stats_cron_schedule'):
         rsync(os.path.join(charm_dir(), 'files', 'check_rabbitmq_queues.py'),
               os.path.join(NAGIOS_PLUGINS, 'check_rabbitmq_queues.py'))
-    if config('management_plugin'):
+    if management_plugin_enabled():
         rsync(os.path.join(charm_dir(), 'files', 'check_rabbitmq_cluster.py'),
               os.path.join(NAGIOS_PLUGINS, 'check_rabbitmq_cluster.py'))
 
@@ -1467,7 +1482,7 @@ def remove_nrpe_files():
         # `stats_cron_schedule` isn't in the config
         remove_file(os.path.join(NAGIOS_PLUGINS, 'check_rabbitmq_queues.py'))
 
-    if not config('management_plugin'):
+    if not management_plugin_enabled():
         # This script is redundant if the value `management_plugin` isn't
         # in the config
         remove_file(os.path.join(NAGIOS_PLUGINS, 'check_rabbitmq_cluster.py'))
@@ -1676,7 +1691,7 @@ def nrpe_update_cluster_check(nrpe_compat, user, password):
     :param password: password of NRPE user
     :type: str
     """
-    if config('management_plugin'):
+    if management_plugin_enabled():
         cmd = '{}/check_rabbitmq_cluster.py --port {} ' \
               '--user {} --password {}'.format(
                   NAGIOS_PLUGINS, get_managment_port(), user, password)

hooks/rabbitmq_server_relations.py

@@ -722,7 +722,7 @@ def config_changed(check_deferred_restarts=True):
     chown(RABBIT_DIR, rabbit.RABBIT_USER, rabbit.RABBIT_USER)
     chmod(RABBIT_DIR, 0o775)
 
-    if config('management_plugin') is True:
+    if rabbit.management_plugin_enabled():
         rabbit.enable_plugin(MAN_PLUGIN)
         open_port(rabbit.get_managment_port())
     else:

unit_tests/test_rabbit_utils.py

@@ -47,6 +47,7 @@ TO_PATCH = [
     'config',
     'is_unit_paused_set',
     'local_unit',
+    'lsb_release',
 ]
 
 
@@ -158,6 +159,8 @@ class UtilsTests(CharmTestCase):
         self.nrpe_compat = mock.MagicMock()
         self.nrpe_compat.add_check = mock.MagicMock()
         self.nrpe_compat.remove_check = mock.MagicMock()
+        self.lsb_release.return_value = {
+            'DISTRIB_CODENAME': 'focal'}
 
     def tearDown(self):
         super(UtilsTests, self).tearDown()
@@ -1453,3 +1456,17 @@ class UtilsTests(CharmTestCase):
             self.assertEqual(generated_policy, policy)
 
             mock_set_policy.reset_mock()
+
+    @mock.patch('rabbit_utils.config')
+    def test_management_plugin_enabled(self, mock_config):
+        mock_config.side_effect = self.test_config
+        self.lsb_release.return_value = {
+            'DISTRIB_CODENAME': 'focal'}
+        self.test_config.set('management_plugin', True)
+        self.assertTrue(rabbit_utils.management_plugin_enabled())
+        self.test_config.set('management_plugin', False)
+        self.assertFalse(rabbit_utils.management_plugin_enabled())
+        self.lsb_release.return_value = {
+            'DISTRIB_CODENAME': 'xenial'}
+        self.test_config.set('management_plugin', True)
+        self.assertFalse(rabbit_utils.management_plugin_enabled())

unit_tests/test_rabbitmq_server_relations.py

@@ -419,6 +419,7 @@ class RelationUtil(CharmTestCase):
         mock_add_check.reset_mock()
         mock_remove_check.reset_mock()
         self.test_config.unset('stats_cron_schedule')
+        self.test_config.set('management_plugin', False)
         rabbitmq_server_relations.update_nrpe_checks()
         mock_remove_file.assert_has_calls([
             call(stats_confile),