Resetting session persisnence for a VIP.

This change allows to reset session persistence, if it
was configured for a VIP. It's possible by passing None
value for session persistence through the REST API.

Change-Id: I8690850d0589065502a8eb774d51fe40851624f8
Fixes: bug #1109101

quantum/api/v2/attributes.py

@@ -338,6 +338,10 @@ def convert_none_to_empty_list(value):
     return [] if value is None else value
 
 
+def convert_none_to_empty_dict(value):
+    return {} if value is None else value
+
+
 def convert_to_list(data):
     if data is None:
         return []

quantum/db/loadbalancer/loadbalancer_db.py

@@ -260,7 +260,7 @@ class LoadBalancerPluginDb(LoadBalancerPluginBase):
         with context.session.begin(subtransactions=True):
             pool_db.update({'vip_id': vip_id})
 
-    def _update_vip_session_persistence_info(self, context, vip_id, info):
+    def _update_vip_session_persistence(self, context, vip_id, info):
         vip = self._get_resource(context, Vip, vip_id)
 
         with context.session.begin(subtransactions=True):
@@ -279,10 +279,10 @@ class LoadBalancerPluginDb(LoadBalancerPluginBase):
                 vip.session_persistence = sesspersist_db
             context.session.add(vip)
 
-    def _delete_sessionpersistence(self, context, id):
+    def _delete_session_persistence(self, context, vip_id):
         with context.session.begin(subtransactions=True):
             sess_qry = context.session.query(SessionPersistence)
-            sess_qry.filter_by(vip_id=id).delete()
+            sess_qry.filter_by(vip_id=vip_id).delete()
 
     def create_vip(self, context, vip):
         v = vip['vip']
@@ -325,12 +325,12 @@ class LoadBalancerPluginDb(LoadBalancerPluginBase):
     def update_vip(self, context, id, vip):
         v = vip['vip']
 
-        sesspersist_info = v.pop('session_persistence', None)
+        sess_persist = v.pop('session_persistence', None)
         with context.session.begin(subtransactions=True):
-            if sesspersist_info:
+            if sess_persist:
-                self._update_vip_session_persistence_info(context,
+                self._update_vip_session_persistence(context, id, sess_persist)
-                                                          id,
+            else:
-                                                          sesspersist_info)
+                self._delete_session_persistence(context, id)
 
             vip_db = self._get_resource(context, Vip, id)
             old_pool_id = vip_db['pool_id']

quantum/extensions/loadbalancer.py

@@ -88,6 +88,7 @@ RESOURCE_ATTRIBUTE_MAP = {
                     'validate': {'type:uuid': None},
                     'is_visible': True},
         'session_persistence': {'allow_post': True, 'allow_put': True,
+                                'convert_to': attr.convert_none_to_empty_dict,
                                 'default': {},
                                 'validate': {'type:dict': None},
                                 'is_visible': True},

quantum/tests/unit/db/loadbalancer/test_db_loadbalancer.py

@@ -438,6 +438,26 @@ class TestLoadBalancer(LoadBalancerPluginDbTestCase):
             for k, v in keys:
                 self.assertEqual(vip['vip'][k], v)
 
+    def test_reset_session_persistence(self):
+        name = 'vip4'
+        session_persistence = {'type': "HTTP_COOKIE",
+                               'cookie_name': "cookie_name"}
+
+        update_info = {'vip': {'session_persistence': None}}
+
+        with self.vip(name=name, session_persistence=session_persistence) as v:
+            # Ensure that vip has been created properly
+            self.assertEqual(v['vip']['session_persistence'],
+                             session_persistence)
+
+            # Try resetting session_persistence
+            req = self.new_update_request('vips', update_info, v['vip']['id'])
+            res = self.deserialize('json', req.get_response(self.ext_api))
+
+            # If session persistence has been removed, it won't be present in
+            # the response.
+            self.assertNotIn('session_persistence', res['vip'])
+
     def test_update_vip(self):
         name = 'new_vip'
         keys = [('name', name),