Adds Cascade Delete for LoadBalancers to Octavia Driver

This implements the cascade delete functionality for the
Octavia reference driver.

Change-Id: I9127826ef72a1e144d3005e68d4307ee7efb3e79
Depends-On: I0fd88923dc76e573b92d83f68d292ded913b13a6

neutron_lbaas/db/loadbalancer/loadbalancer_dbv2.py

@@ -242,8 +242,10 @@ class LoadBalancerPluginDbv2(base_db.CommonDbMixin,
             if cascade:
                 lb = self.get_loadbalancer(context, id)
                 for pool in lb.pools:
-                    self.delete_healthmonitor(context, pool.healthmonitor_id)
-                    self.delete_pool(pool.id)
+                    if pool.healthmonitor_id:
+                        self.delete_healthmonitor(
+                            context, pool.healthmonitor_id)
+                    self.delete_pool(context, pool.id)
                 for listener in lb.listeners:
                     # todo (xgerman): delete L7
                     self.delete_listener(context, listener.id)

neutron_lbaas/drivers/driver_base.py

@@ -94,7 +94,7 @@ class BaseLoadBalancerManager(driver_mixins.BaseRefreshMixin,
 
     @property
     def deletes_cascade(self):
-        """Does this driver need to allocate its own virtual IPs"""
+        """Does this driver cascade delete LB"""
         return False
 
     def create_and_allocate_vip(self, context, obj):

neutron_lbaas/drivers/octavia/driver.py

@@ -101,7 +101,7 @@ def thread_op(manager, entity, delete=False, lb_create=False):
 def async_op(func):
     @wraps(func)
     def func_wrapper(*args, **kwargs):
-        d = (func.__name__ == 'delete')
+        d = (func.__name__ == 'delete' or func.__name__ == 'delete_cascade')
         lb_create = ((func.__name__ == 'create') and
                      isinstance(args[0], LoadBalancerManager))
         try:
@@ -196,6 +196,10 @@ class LoadBalancerManager(driver_base.BaseLoadBalancerManager):
     def allocates_vip(self):
         return cfg.CONF.octavia.allocates_vip
 
+    @property
+    def deletes_cascade(self):
+        return True
+
     def create_and_allocate_vip(self, context, lb):
         self.create(context, lb)
 
@@ -238,6 +242,10 @@ class LoadBalancerManager(driver_base.BaseLoadBalancerManager):
     def get(self, lb):
         return self.driver.req.get(self._url(lb, lb.id))
 
+    @async_op
+    def delete_cascade(self, context, lb):
+        self.driver.req.delete(self._url(lb, lb.id) + '/delete_cascade')
+
 
 class ListenerManager(driver_base.BaseListenerManager):
 

neutron_lbaas/tests/unit/drivers/octavia/test_octavia_driver.py

@@ -43,6 +43,10 @@ class ManagerTest(object):
         self.manager.delete(self.context, model)
         self.mocked_req.delete.assert_called_with(url)
 
+    def delete_cascade(self, model, url):
+        self.manager.delete_cascade(self.context, model)
+        self.mocked_req.delete.assert_called_with(url)
+
     # TODO(Banashankar) : Complete refresh function. Need more info.
     def refresh(self):
         pass
@@ -137,7 +141,7 @@ class TestOctaviaDriver(BaseOctaviaDriverTest):
         m.update(lb, lb, lb_url_id, args)
 
         # delete LB test
-        m.delete(lb, lb_url_id)
+        m.delete_cascade(lb, lb_url_id + '/delete_cascade')
 
         # TODO(Banashankar) : refresh n stats fucntions are not yet done.
         #m.refresh()