[VNC OpenStack] Fix concurrency project deletion

In mutli API server setup, the sync domains/projects VNC OpenStack
greenthread of one of the servers can try to remove and purge resource related
to a project which another server already purged. That results to not found
API exceptions. That patch catches that exceptions and abandons to purge
the project.
That also reveals an issue in permission code that checks if the
deletion is authorized which fails to read the resource as it was
already deleted.

Change-Id: I140cf5b7f4bd4d7798db18a7afd3b0d6168ea6b1
Closes-Bug: #1724179
Closes-Bug: #1724194

src/config/api-server/vnc_perms.py

@@ -239,11 +239,17 @@ def check_perms_delete(self, request, obj_type, obj_uuid, parent_uuid):
 
         if self._rbac:
             # delete only allowed for owner
-            (ok, obj_dict) = self._server_mgr._db_conn.dbe_read(obj_type,
-                             obj_uuid, obj_fields=['perms2'])
-            obj_owner=obj_dict['perms2']['owner']
+            try:
+                ok, result = self._server_mgr._db_conn.dbe_read(
+                    obj_type, obj_uuid, obj_fields=['perms2'])
+            except NoIdError as e:
+                return False, (404, str(e))
+            if not ok:
+                return False, (500, result)
+            obj_dict = result
+            obj_owner = obj_dict['perms2']['owner']
             return self.validate_perms_rbac(request, parent_uuid, PERMS_W,
-                                            obj_owner_for_delete = obj_owner)
+                                            obj_owner_for_delete=obj_owner)
         elif self._auth_needed:
             return self.validate_perms(request, parent_uuid, PERMS_W)
         else:

src/config/vnc_openstack/vnc_openstack/__init__.py

@@ -937,11 +937,21 @@ def post_project_create(self, proj_dict):
 
     @wait_for_api_server_connection
     def pre_project_delete(self, proj_uuid):
-        proj_obj = self._vnc_lib.project_read(id=proj_uuid)
+        try:
+            proj_obj = self._vnc_lib.project_read(id=proj_uuid)
+        except vnc_exc.NoIdError:
+            # another api server has brought that project deletion
+            return
         sec_groups = proj_obj.get_security_groups()
         for group in sec_groups or []:
             if group['to'][2] == 'default':
-                self._vnc_lib.security_group_delete(id=group['uuid'])
+                try:
+                    # another api server has brought that project deletion and
+                    # its default security group
+                    self._vnc_lib.security_group_delete(id=group['uuid'])
+                except vnc_exc.NoIdError:
+                    pass
+                return
     # end pre_project_delete
 
     @wait_for_api_server_connection