Merge "handle gw_info outside of the db transaction on router creation"

neutron/db/l3_db.py

@@ -174,11 +174,17 @@ class L3_NAT_dbonly_mixin(l3.RouterPluginBase):
         r = router['router']
         gw_info = r.pop(EXTERNAL_GW_INFO, None)
         tenant_id = self._get_tenant_id_for_create(context, r)
-        with context.session.begin(subtransactions=True):
-            router_db = self._create_router_db(context, r, tenant_id)
+        router_db = self._create_router_db(context, r, tenant_id)
+        try:
             if gw_info:
                 self._update_router_gw_info(context, router_db['id'],
                                             gw_info, router=router_db)
+        except Exception:
+            with excutils.save_and_reraise_exception():
+                LOG.exception(_LE("An exception occurred while creating "
+                                  "the router: %s"), router)
+                self.delete_router(context, router_db.id)
+
         return self._make_router_dict(router_db)
 
     def _update_router_db(self, context, router_id, data, gw_info):

neutron/tests/unit/extensions/test_l3.py

@@ -2477,6 +2477,23 @@ class L3NatTestCaseBase(L3NatTestCaseMixin):
                         fip['floatingip']['floating_ip_address'])
                 self.assertEqual(floating_ip.version, 4)
 
+    def test_create_router_gateway_fails(self):
+        # Force _update_router_gw_info failure
+        plugin = manager.NeutronManager.get_service_plugins()[
+            service_constants.L3_ROUTER_NAT]
+        ctx = context.Context('', 'foo')
+        plugin._update_router_gw_info = mock.Mock(
+            side_effect=n_exc.NeutronException)
+        data = {'router': {
+            'name': 'router1', 'admin_state_up': True,
+            'external_gateway_info': {'network_id': 'some_uuid'}}}
+
+        # Verify router doesn't persist on failure
+        self.assertRaises(n_exc.NeutronException,
+                          plugin.create_router, ctx, data)
+        routers = plugin.get_routers(ctx)
+        self.assertEqual(0, len(routers))
+
 
 class L3AgentDbTestCaseBase(L3NatTestCaseMixin):