From 32e4d822c101793a44f669ab1d12b8cb946e33fa Mon Sep 17 00:00:00 2001
From: Liam Young <liam.young@canonical.com>
Date: Mon, 5 Nov 2018 18:36:06 +0000
Subject: [PATCH] Only check for one unit for container scoped rels.

When checking goal state, only look for one unit to be available
when examining container scoped relations as a principle unit only
ever has a relation with a single unit of a given subordinate
application.

Change-Id: I02f34358060c98c0702d3d7b58d52427c2a0445a
Closes-Bug: #1801754
---
 hooks/keystone_utils.py           | 25 +++++++++++++++++++++++--
 unit_tests/test_keystone_utils.py | 24 ++++++++++++++++++++++--
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/hooks/keystone_utils.py b/hooks/keystone_utils.py
index 8e1b516c..5906e453 100644
--- a/hooks/keystone_utils.py
+++ b/hooks/keystone_utils.py
@@ -76,6 +76,7 @@ from charmhelpers.core.decorators import (
 
 from charmhelpers.core.hookenv import (
     atexit,
+    cached,
     config,
     expected_peer_units,
     expected_related_units,
@@ -84,6 +85,7 @@ from charmhelpers.core.hookenv import (
     leader_set,
     log,
     local_unit,
+    metadata,
     relation_get,
     relation_set,
     relation_id,
@@ -2239,6 +2241,18 @@ def fernet_keys_rotate_and_sync(log_func=log):
              level=INFO)
 
 
+@cached
+def container_scoped_relations():
+    '''Get all the container scoped relations'''
+    md = metadata()
+    relations = []
+    for relation_type in ('provides', 'requires', 'peers'):
+        for relation in md.get(relation_type, []):
+            if md[relation_type][relation].get('scope') == 'container':
+                relations.append(relation)
+    return relations
+
+
 def is_expected_scale():
     """Query juju goal-state to determine whether our peer- and dependency-
     relations are at the expected scale.
@@ -2269,8 +2283,15 @@ def is_expected_scale():
         for dep in deps:
             if not dep[1]:
                 return False
-            if (len(related_units(relid=dep[1])) <
-                    len(list(expected_related_units(reltype=dep[0])))):
+            # Goal state returns every unit even for container scoped
+            # relations but the charm only ever has a relation with
+            # the local unit.
+            if dep[0] in container_scoped_relations():
+                expected_count = 1
+            else:
+                expected_count = len(
+                    list(expected_related_units(reltype=dep[0])))
+            if len(related_units(relid=dep[1])) < expected_count:
                 return False
     except NotImplementedError:
         return True
diff --git a/unit_tests/test_keystone_utils.py b/unit_tests/test_keystone_utils.py
index b95f3bad..51ebc7d7 100644
--- a/unit_tests/test_keystone_utils.py
+++ b/unit_tests/test_keystone_utils.py
@@ -1310,13 +1310,16 @@ class TestKeystoneUtils(CharmTestCase):
         mock_fernet_rotate.assert_called_once_with()
         mock_key_leader_set.assert_called_once_with()
 
+    @patch.object(utils, 'container_scoped_relations')
     @patch.object(utils, 'expected_related_units')
     @patch.object(utils, 'expected_peer_units')
     @patch.object(utils, 'related_units')
     @patch.object(utils, 'expect_ha')
     @patch.object(utils, 'relation_ids')
     def test_is_expected_scale(self, relation_ids, expect_ha, related_units,
-                               expected_peer_units, expected_related_units):
+                               expected_peer_units, expected_related_units,
+                               container_scoped_relations):
+        container_scoped_relations.return_value = ['ha']
         relation_ids.return_value = ['FAKE_RID']
         expect_ha.return_value = False
         related_units.return_value = ['unit/0', 'unit/1', 'unit/2']
@@ -1328,13 +1331,16 @@ class TestKeystoneUtils(CharmTestCase):
             call(reltype='shared-db')])
         related_units.assert_called_with(relid='FAKE_RID')
 
+    @patch.object(utils, 'container_scoped_relations')
     @patch.object(utils, 'expected_related_units')
     @patch.object(utils, 'expected_peer_units')
     @patch.object(utils, 'related_units')
     @patch.object(utils, 'expect_ha')
     @patch.object(utils, 'relation_ids')
     def test_is_expected_scale_ha(self, relation_ids, expect_ha, related_units,
-                                  expected_peer_units, expected_related_units):
+                                  expected_peer_units, expected_related_units,
+                                  container_scoped_relations):
+        container_scoped_relations.return_value = ['ha']
         relation_ids.return_value = ['FAKE_RID']
         expect_ha.return_value = True
         related_units.return_value = ['unit/0', 'unit/1', 'unit/2']
@@ -1381,3 +1387,17 @@ class TestKeystoneUtils(CharmTestCase):
         expected_peer_units.side_effect = NotImplementedError
         self.assertTrue(utils.is_expected_scale())
         expected_related_units.assert_not_called()
+
+    @patch.object(utils, 'metadata')
+    def test_container_scoped_relations(self, metadata):
+        _metadata = {
+            'provides': {
+                'amqp': {'interface': 'rabbitmq'},
+                'identity-service': {'interface': 'keystone'},
+                'ha': {
+                    'interface': 'hacluster',
+                    'scope': 'container'}},
+            'peers': {
+                'cluster': {'interface': 'openstack-ha'}}}
+        metadata.return_value = _metadata
+        self.assertEqual(utils.container_scoped_relations(), ['ha'])