allow getting resource request of every bound ports of an instance

This patch adds a new network api method
get_requested_resource_for_instance() to query neutron about the
resource needs of the ports currently bound to an instance. A later
patch will use this to properly allocate resource for the ports during
migration.

blueprint: support-move-ops-with-qos-ports

Change-Id: I56ea5ee94139dfa2cdf6bb76656bca2902e7ea9c

Author: Balazs Gibizer

nova/network/base_api.py

@@ -258,6 +258,15 @@ def _get_instance_nw_info(self, context, instance, **kwargs):
         """Template method, so a subclass can implement for neutron/network."""
         raise NotImplementedError()
 
+    def get_requested_resource_for_instance(self, context, instance_uuid):
+        """Collect resource requests from the ports associated to the instance
+
+        :param context: nova request context
+        :param instance_uuid: The UUID of the instance
+        :return: A list of RequestGroup objects
+        """
+        raise NotImplementedError()
+
     def validate_networks(self, context, requested_networks, num_instances):
         """validate the networks passed at the time of creating
         the server.

nova/network/neutronv2/api.py

@@ -2216,6 +2216,31 @@ def _ports_needed_per_instance(self, context, neutron, requested_networks):
                         raise exception.NetworkNotFound(network_id=id_str)
         return ports_needed_per_instance
 
+    def get_requested_resource_for_instance(self, context, instance_uuid):
+        """Collect resource requests from the ports associated to the instance
+
+        :param context: nova request context
+        :param instance_uuid: The UUID of the instance
+        :return: A list of RequestGroup objects
+        """
+
+        neutron = get_client(context)
+        # get the ports associated to this instance
+        data = neutron.list_ports(
+            device_id=instance_uuid, fields=['id', 'resource_request'])
+        resource_requests = []
+
+        for port in data.get('ports', []):
+            if port.get('resource_request'):
+                # NOTE(gibi): explicitly orphan the RequestGroup by setting
+                # context=None as we never intended to save it to the DB.
+                resource_requests.append(
+                    objects.RequestGroup.from_port_request(
+                        context=None, port_uuid=port['id'],
+                        port_resource_request=port['resource_request']))
+
+        return resource_requests
+
     def validate_networks(self, context, requested_networks, num_instances):
         """Validate that the tenant can use the requested networks.
 

nova/tests/unit/network/test_neutronv2.py

@@ -5813,6 +5813,74 @@ def test_migrate_instance_start_get_error(self, get_client_mock):
                 raise_exc=False,
                 global_request_id=self.context.global_id)])
 
+    @mock.patch('nova.network.neutronv2.api.get_client')
+    def test_get_requested_resource_for_instance_no_resource_request(
+            self, mock_get_client):
+        mock_client = mock_get_client.return_value
+
+        ports = {'ports': [
+            {
+                'id': uuids.port1,
+                'device_id': uuids.isnt1,
+            }
+        ]}
+        mock_client.list_ports.return_value = ports
+
+        request_groups = self.api.get_requested_resource_for_instance(
+            self.context, uuids.inst1)
+
+        mock_client.list_ports.assert_called_with(
+            device_id=uuids.inst1, fields=['id', 'resource_request'])
+        self.assertEqual([], request_groups)
+
+    @mock.patch('nova.network.neutronv2.api.get_client')
+    def test_get_requested_resource_for_instance_no_ports(
+            self, mock_get_client):
+        mock_client = mock_get_client.return_value
+
+        ports = {'ports': []}
+        mock_client.list_ports.return_value = ports
+
+        request_groups = self.api.get_requested_resource_for_instance(
+            self.context, uuids.inst1)
+
+        mock_client.list_ports.assert_called_with(
+            device_id=uuids.inst1, fields=['id', 'resource_request'])
+        self.assertEqual([], request_groups)
+
+    @mock.patch('nova.network.neutronv2.api.get_client')
+    def test_get_requested_resource_for_instance_with_multiple_ports(
+            self, mock_get_client):
+        mock_client = mock_get_client.return_value
+
+        ports = {'ports': [
+            {
+                'id': uuids.port1,
+                'device_id': uuids.isnt1,
+                'resource_request': {
+                    'resources': {'NET_BW_EGR_KILOBIT_PER_SEC': 10000}}
+            },
+            {
+                'id': uuids.port2,
+                'device_id': uuids.isnt1,
+                'resource_request': {}
+            },
+        ]}
+        mock_client.list_ports.return_value = ports
+
+        request_groups = self.api.get_requested_resource_for_instance(
+            self.context, uuids.inst1)
+
+        mock_client.list_ports.assert_called_with(
+            device_id=uuids.inst1, fields=['id', 'resource_request'])
+        self.assertEqual(1, len(request_groups))
+        self.assertEqual(
+            {'NET_BW_EGR_KILOBIT_PER_SEC': 10000},
+            request_groups[0].resources)
+        self.assertEqual(
+            uuids.port1,
+            request_groups[0].requester_id)
+
 
 class TestNeutronv2ModuleMethods(test.NoDBTestCase):