Return 400 if creating a distributed router on old NVP platforms

Without checking for the right NVP support, creating a distributed
router will silently fail, i.e. ithe 'distributed' attribute will
be ignored and a centralized router will be created instead.

Supports blueprint nvp-distributed-router

Change-Id: If8e40c0907d78c30f9ba918aaaff57e58ebb8055

neutron/plugins/nicira/NeutronPlugin.py

@@ -1639,6 +1639,12 @@ class NvpPluginV2(db_base_plugin_v2.NeutronDbPluginV2,
             # This will be useful for setting the value if the API request
             # did not specify any value for the 'distributed' attribute
             r['distributed'] = lrouter['distributed']
+        except nvp_exc.NvpInvalidVersion:
+            msg = _("Cannot create a distributed router with the NVP "
+                    "platform currently in execution. Please, try "
+                    "without specifying the 'distributed' attribute.")
+            LOG.exception(msg)
+            raise q_exc.BadRequest(resource='router', msg=msg)
         except NvpApiClient.NvpApiException:
             raise nvp_exc.NvpPluginException(
                 err_msg=_("Unable to create logical router on NVP Platform"))

neutron/plugins/nicira/nvplib.py

@@ -360,7 +360,11 @@ def create_explicit_routing_lrouter(cluster, tenant_id,
 
 @version_dependent
 def create_lrouter(cluster, *args, **kwargs):
-    pass
+    if kwargs.get('distributed', None):
+        v = cluster.api_client.get_nvp_version()
+        if (v.major < 3) or (v.major >= 3 and v.minor < 1):
+            raise nvp_exc.NvpInvalidVersion(version=v)
+        return v
 
 
 def delete_lrouter(cluster, lrouter_id):

neutron/tests/unit/nicira/test_nicira_plugin.py

@@ -480,9 +480,10 @@ class TestNiciraL3NatTestCase(test_l3_plugin.L3NatDBTestCase,
     def test_router_create_with_gwinfo_and_l3_ext_net_with_vlan(self):
         self._test_router_create_with_gwinfo_and_l3_ext_net(444)
 
-    def _test_router_create_with_distributed(self, dist_input, dist_expected):
+    def _test_router_create_with_distributed(self, dist_input, dist_expected,
+                                             version='3.1', return_code=201):
         self.mock_instance.return_value.get_nvp_version.return_value = (
-            NvpApiClient.NVPVersion('3.1'))
+            NvpApiClient.NVPVersion(version))
 
         data = {'tenant_id': 'whatever'}
         data['name'] = 'router1'
@@ -491,11 +492,14 @@ class TestNiciraL3NatTestCase(test_l3_plugin.L3NatDBTestCase,
             'routers', {'router': data}, self.fmt)
         try:
             res = router_req.get_response(self.ext_api)
+            self.assertEqual(return_code, res.status_int)
+            if res.status_int == 201:
                 router = self.deserialize(self.fmt, res)
                 self.assertIn('distributed', router['router'])
                 self.assertEqual(dist_expected,
                                  router['router']['distributed'])
         finally:
+            if res.status_int == 201:
                 self._delete('routers', router['router']['id'])
 
     def test_router_create_distributed(self):
@@ -507,6 +511,9 @@ class TestNiciraL3NatTestCase(test_l3_plugin.L3NatDBTestCase,
     def test_router_create_distributed_unspecified(self):
         self._test_router_create_with_distributed(None, False)
 
+    def test_router_create_distributed_returns_400(self):
+        self._test_router_create_with_distributed(True, None, '3.0', 400)
+
     def test_router_create_nvp_error_returns_500(self, vlan_id=None):
         with mock.patch.object(nvplib,
                                'create_router_lport',