Number of heat queues will keep growing forever after heat-engine restarts

Set TTL as a solution for topic queue engine_worker and heat-engine-listener
to avoid them growing all the time after heat-engin restarts.

This is heat part.

Closes-Bug: 1925436
Change-Id: I196346e4ca869efab45d1c2aafb1420b2a917d39

config.yaml

@@ -74,6 +74,12 @@ options:
     default: openstack
     type: string
     description: RabbitMQ virtual host to request access on rabbitmq-server.
+  ttl:
+    type: int
+    default: 3600000
+    description: |
+      TTL in MS for heat queues in the openstack vhost. Defaults to
+      1 hour, but can be tuned up or down depending on deployment requirements.
   encryption-key:
     default: ""
     type: string

hooks/heat_relations.py

@@ -171,6 +171,8 @@ def config_changed():
         cluster_joined(relation_id=rid)
     for r_id in relation_ids('ha'):
         ha_joined(relation_id=r_id)
+    for rid in relation_ids('amqp'):
+        amqp_joined(relation_id=rid)
 
     # call the policy overrides handler which will install any policy overrides
     policyd.maybe_do_policyd_overrides_on_config_changed(
@@ -221,7 +223,10 @@ def upgrade_charm():
 @hooks.hook('amqp-relation-joined')
 def amqp_joined(relation_id=None):
     relation_set(relation_id=relation_id,
-                 username=config('rabbit-user'), vhost=config('rabbit-vhost'))
+                 username=config('rabbit-user'), vhost=config('rabbit-vhost'),
+                 ttlname='heat_expiry',
+                 ttlreg='heat-engine-listener|engine_worker',
+                 ttl=config('ttl'))
 
 
 @hooks.hook('amqp-relation-changed')

unit_tests/test_heat_relations.py

@@ -226,14 +226,18 @@ class HeatRelationTests(CharmTestCase):
         self.relation_set.assert_called_with(
             username='heat',
             vhost='openstack',
-            relation_id=None)
+            relation_id=None,
+            ttlname='heat_expiry',
+            ttlreg='heat-engine-listener|engine_worker',
+            ttl=3600000)
 
     def test_amqp_joined_passes_relation_id(self):
         "Ensures relation_id correct passed to relation_set"
         relations.amqp_joined(relation_id='heat:1')
-        self.relation_set.assert_called_with(username='heat',
-                                             vhost='openstack',
-                                             relation_id='heat:1')
+        self.relation_set.assert_called_with(
+            username='heat', vhost='openstack', relation_id='heat:1',
+            ttlname='heat_expiry',
+            ttlreg='heat-engine-listener|engine_worker', ttl=3600000)
 
     @patch.object(relations, 'CONFIGS')
     def test_amqp_changed_relation_data(self, configs):