Move VM state check post VIF required check

The VIF code determines if a VM is in a valid state for a plug vif, and
then determines if a plug vif is needed.  This can lead to odd scenarios
where the plug of the VIF will fail, when in fact no VIF plugs were
actually required.

This change set swaps the checks around to prevent this failure.

Change-Id: Ic759080fa2848eee179f322dd047bce3048624e8
Closes-Bug: 1466698

nova_powervm/tests/virt/powervm/tasks/test_network.py

@@ -148,8 +148,6 @@ class TestNetwork(test.TestCase):
             {'address': 'aa:bb:cc:dd:ee:ff'}, {'address': 'aa:bb:cc:dd:ee:11'}
         ]
 
-        mock_state.return_value = True
-
         # Run method
         p_vifs = tf_net.PlugVifs(mock.MagicMock(), self.apt, inst, net_info,
                                  'host_uuid')
@@ -160,17 +158,27 @@ class TestNetwork(test.TestCase):
         self.assertEqual(0, mock_vm_crt.call_count)
         self.assertEqual([], resp)
 
+        # State check shouldn't have even been invoked as no creates were
+        # required
+        self.assertEqual(0, mock_state.call_count)
+
     @mock.patch('nova_powervm.virt.powervm.tasks.network.state_ok_for_plug')
     @mock.patch('nova_powervm.virt.powervm.vm.crt_vif')
-    def test_plug_vifs_invalid_state(self, mock_vm_crt, mock_state):
+    @mock.patch('nova_powervm.virt.powervm.vm.get_cnas')
+    def test_plug_vifs_invalid_state(self, mock_vm_get, mock_vm_crt,
+                                     mock_state):
         """Tests that a crt_vif fails when the LPAR state is bad."""
         inst = objects.Instance(**powervm.TEST_INSTANCE)
 
+        # Mock up the CNA response.  Only doing one for simplicity
+        mock_vm_get.return_value = []
+        net_info = [{'address': 'aa:bb:cc:dd:ee:ff'}]
+
         # Mock that the state is incorrect
         mock_state.return_value = False
 
         # Run method
-        p_vifs = tf_net.PlugVifs(mock.MagicMock(), self.apt, inst, [],
+        p_vifs = tf_net.PlugVifs(mock.MagicMock(), self.apt, inst, net_info,
                                  'host_uuid')
         self.assertRaises(exception.VirtualInterfaceCreateException,
                           p_vifs.execute, mock.Mock())

nova_powervm/virt/powervm/tasks/network.py

@@ -148,15 +148,6 @@ class PlugVifs(task.Task):
         LOG.info(_LI('Plugging the Network Interfaces to instance %s'),
                  self.instance.name)
 
-        # Check to see if the LPAR is OK to add VIFs to.
-        if not state_ok_for_plug(lpar_wrap):
-            LOG.error(_LE('Unable to create VIF(s) for instance %(sys)s.  The '
-                          'VM was in a state where VIF plugging is not '
-                          'acceptable.  The system may be running without an '
-                          'active RMC connection.'),
-                      {'sys': self.instance.name}, instance=self.instance)
-            raise exception.VirtualInterfaceCreateException()
-
         # Get the current adapters on the system
         cna_w_list = vm.get_cnas(self.adapter, self.instance, self.host_uuid)
 
@@ -173,6 +164,15 @@ class PlugVifs(task.Task):
         if len(crt_vifs) == 0:
             return []
 
+        # Check to see if the LPAR is OK to add VIFs to.
+        if not state_ok_for_plug(lpar_wrap):
+            LOG.error(_LE('Unable to create VIF(s) for instance %(sys)s.  The '
+                          'VM was in a state where VIF plugging is not '
+                          'acceptable.  The system may be running without an '
+                          'active RMC connection.'),
+                      {'sys': self.instance.name}, instance=self.instance)
+            raise exception.VirtualInterfaceCreateException()
+
         # For the VIFs, run the creates (and wait for the events back)
         try:
             with self.virt_api.wait_for_instance_event(