networkutils: specializes the exception raised by _get_vnic_settings

VMs can be destroyed before their vNICs had a chance to be bound.
When trying to bind a vNIC of an already-destroyed VM, os-win will
raise a HyperVException.

This patch specializes the exception raised in this case, allowing
consumers to treat this case differently.

Change-Id: I8fabe8799d0e57dcc5627d67b3962c4f11f08f1e
Closes-Bug: #1684045

os_win/exceptions.py

@@ -91,6 +91,10 @@ class HyperVPortNotFoundException(NotFound, HyperVException):
     msg_fmt = _("Switch port not found: %(port_name)s")
 
 
+class HyperVvNicNotFound(NotFound, HyperVException):
+    msg_fmt = _("vNic not found: %(vnic_name)s")
+
+
 class Invalid(OSWinException):
     pass
 

os_win/tests/unit/utils/network/test_networkutils.py

@@ -162,6 +162,22 @@ class NetworkUtilsTestCase(test_base.OsWinBaseTestCase):
             mock.sentinel.switch_port_name)
         self.assertEqual(mock.sentinel.mac_address, actual_mac_address)
 
+    @ddt.data([], [mock.sentinel.nic_sd])
+    def test_get_vnic_settings(self, nic_sds):
+        mock_nic_sd = self.netutils._conn.Msvm_SyntheticEthernetPortSettingData
+        mock_nic_sd.return_value = nic_sds
+
+        if not nic_sds:
+            self.assertRaises(exceptions.HyperVvNicNotFound,
+                              self.netutils._get_vnic_settings,
+                              mock.sentinel.vnic_name)
+        else:
+            nic_sd = self.netutils._get_vnic_settings(mock.sentinel.vnic_name)
+            self.assertEqual(mock.sentinel.nic_sd, nic_sd)
+
+        mock_nic_sd.assert_called_once_with(
+            ElementName=mock.sentinel.vnic_name)
+
     @mock.patch.object(networkutils, 'patcher')
     @mock.patch.object(networkutils.tpool, 'execute')
     @mock.patch.object(networkutils.NetworkUtils, '_get_event_wql_query')

os_win/utils/network/networkutils.py

@@ -233,8 +233,7 @@ class NetworkUtils(baseutils.BaseUtilsVirt):
         vnic_settings = self._conn.Msvm_SyntheticEthernetPortSettingData(
             ElementName=vnic_name)
         if not vnic_settings:
-            raise exceptions.HyperVException(
-                message=_('Vnic not found: %s') % vnic_name)
+            raise exceptions.HyperVvNicNotFound(vnic_name=vnic_name)
         return vnic_settings[0]
 
     def get_vnic_event_listener(self, event_type):