Add custom property for ``heartbeat_key``

Change-Id: Icd328e0b75cfb712b1519a6e2184b8ca0b6b137f

src/layer.yaml

@@ -1,4 +1,5 @@
 includes:
+  - layer:leadership
   - layer:openstack-api
   - interface:mysql-shared
   - interface:rabbitmq

src/lib/charm/openstack/octavia.py

@@ -20,6 +20,8 @@ import charms_openstack.charm
 import charms_openstack.adapters
 import charms_openstack.ip as os_ip
 
+import charms.leadership as leadership
+
 import charmhelpers.core.host as ch_host
 
 OCTAVIA_DIR = '/etc/octavia'
@@ -95,3 +97,7 @@ class OctaviaCharm(charms_openstack.charm.HAOpenStackCharm):
                                        OCTAVIA_WEBSERVER_SITE])
                 ch_host.service_reload('apache2',
                                        restart_on_failure=True)
+
+    @charms_openstack.adapters.config_property
+    def heartbeat_key(self):
+        return leadership.leader_get('heartbeat-key')

src/reactive/octavia_handlers.py

@@ -12,7 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import uuid
+
 import charms.reactive as reactive
+import charms.leadership as leadership
 
 import charms_openstack.charm as charm
 
@@ -28,9 +31,17 @@ charm.use_defaults(
     'update-status')
 
 
+@reactive.when('leadership.is_leader')
+@reactive.when_not('leadership.set.heartbeat-key')
+def generate_heartbeat_key():
+    """Generate a unique key for ``heartbeat_key`` configuration option."""
+    leadership.leader_set({'heartbeat-key': str(uuid.uuid4())})
+
+
 @reactive.when('shared-db.available')
 @reactive.when('identity-service.available')
 @reactive.when('amqp.available')
+@reactive.when('leadership.set.heartbeat-key')
 def render(*args):
     """
     Render the configuration for Octavia when all interfaces are available.

src/templates/rocky/octavia.conf

@@ -1,6 +1,9 @@
 [DEFAULT]
 debug = {{ options.debug }}
 
+[health_manager]
+heartbeat_key = {{ options.heartbeat_key }}
+
 [database]
 {% include "parts/database" %}
 

src/tests/bundles/smoke-bionic-rocky.yaml

@@ -19,7 +19,7 @@ applications:
     num_units: 1
   octavia:
     series: bionic
-    charm: octavia
+    charm: ../../../octavia
     num_units: 1
     options:
       openstack-origin: cloud:bionic-rocky

unit_tests/__init__.py

@@ -20,3 +20,8 @@ sys.path.append('src/lib')
 # Mock out charmhelpers so that we can test without it.
 import charms_openstack.test_mocks  # noqa
 charms_openstack.test_mocks.mock_charmhelpers()
+
+import mock
+import charms
+charms.leadership = mock.MagicMock()
+sys.modules['charms.leadership'] = charms.leadership

unit_tests/test_lib_charm_openstack_octavia.py

@@ -55,3 +55,12 @@ class TestOctaviaCharm(Helper):
         self.sp_check_call.assert_called_with(['a2ensite', 'octavia-api'])
         self.service_reload.assert_called_with(
             'apache2', restart_on_failure=True)
+
+    def test_heartbeat_key(self):
+        self.patch('charms.leadership.leader_get', 'leader_get')
+        self.leader_get.return_value = None
+        c = octavia.OctaviaCharm()
+        self.assertEqual(c.heartbeat_key(), None)
+        self.leader_get.return_value = 'FAKE-STORED-UUID-STRING'
+        self.assertEqual(c.heartbeat_key(), 'FAKE-STORED-UUID-STRING')
+        self.leader_get.assert_called_with('heartbeat-key')

unit_tests/test_octavia_handlers.py

@@ -37,13 +37,16 @@ class TestRegisteredHooks(test_utils.TestRegisteredHooks):
             'when': {
                 'render': ('shared-db.available',
                            'identity-service.available',
-                           'amqp.available',),
+                           'amqp.available',
+                           'leadership.set.heartbeat-key',),
                 'init_db': ('config.rendered',),
                 'cluster_connected': ('ha.connected',),
+                'generate_heartbeat_key': ('leadership.is_leader',),
             },
             'when_not': {
                 'init_db': ('db.synced',),
                 'cluster_connected': ('ha.available',),
+                'generate_heartbeat_key': ('leadership.set.heartbeat-key',),
             },
         }
         # test that the hooks were registered via the
@@ -51,7 +54,7 @@ class TestRegisteredHooks(test_utils.TestRegisteredHooks):
         self.registered_hooks_test_helper(handlers, hook_set, defaults)
 
 
-class TestRender(test_utils.PatchHelper):
+class TestOctaviaHandlers(test_utils.PatchHelper):
 
     def setUp(self):
         super().setUp()
@@ -62,6 +65,15 @@ class TestRender(test_utils.PatchHelper):
             self.octavia_charm
         self.provide_charm_instance().__exit__.return_value = None
 
+    def test_generate_heartbeat_key(self):
+        self.patch('charms.leadership.leader_set', 'leader_set')
+        self.patch('uuid.uuid4', 'uuid4')
+        self.uuid4.return_value = fake_uuid4 = 'FAKE-UUID4-STRING'
+        handlers.generate_heartbeat_key()
+        self.leader_set.assert_called_once_with(
+            {'heartbeat-key': fake_uuid4})
+        self.uuid4.assert_called_once_with()
+
     def test_render(self):
         self.patch('charms.reactive.set_state', 'set_state')
         handlers.render('arg1', 'arg2')