Avoid propagating wmi exceptions for soft shutdown

The soft shutdown operation is expected to fail while the VM is
still booting. The issue is that in some cases, os-win will
propagate a wmi exception that Nova cannot handle:

http://paste.openstack.org/raw/800833/

That's because of Msvm_ShutdownComponent.InitiateShutdown, an
asynchronous WMI method that can sometimes throw a wmi exception
right away.

For now, we're taking care of this specific WMI call only. If needed,
we may consider handling all async WMI methods by introducing a new
decorator or helper function.

Change-Id: I9263b14c3c343db6453645152cb9274e38864b48
Closes-Bug: #1907270

os_win/tests/unit/utils/compute/test_vmutils.py

@@ -233,6 +233,19 @@ class VMUtilsTestCase(test_base.OsWinBaseTestCase):
         self._vmutils._jobutils.check_ret_val.assert_called_once_with(
             self._FAKE_RET_VAL, None)
 
+    def test_soft_shutdown_vm_wmi_exc(self):
+        self._lookup_vm()
+        mock_shutdown = mock.MagicMock()
+        mock_shutdown.InitiateShutdown.side_effect = exceptions.x_wmi
+        self._vmutils._conn.Msvm_ShutdownComponent.return_value = [
+            mock_shutdown]
+
+        # We ensure that the wmi exception gets converted.
+        self.assertRaises(
+            exceptions.HyperVException,
+            self._vmutils.soft_shutdown_vm,
+            self._FAKE_VM_NAME)
+
     def test_soft_shutdown_vm_no_component(self):
         mock_vm = self._lookup_vm()
         self._vmutils._conn.Msvm_ShutdownComponent.return_value = []

os_win/utils/compute/vmutils.py

@@ -662,19 +662,26 @@ class VMUtils(baseutils.BaseUtilsVirt):
         return [nic.ElementName for nic in nics]
 
     def soft_shutdown_vm(self, vm_name):
-        vm = self._lookup_vm_check(vm_name, as_vssd=False)
-        shutdown_component = self._conn.Msvm_ShutdownComponent(
-            SystemName=vm.Name)
+        try:
+            vm = self._lookup_vm_check(vm_name, as_vssd=False)
+            shutdown_component = self._conn.Msvm_ShutdownComponent(
+                SystemName=vm.Name)
 
-        if not shutdown_component:
-            # If no shutdown_component is found, it means the VM is already
-            # in a shutdown state.
-            return
+            if not shutdown_component:
+                # If no shutdown_component is found, it means the VM is already
+                # in a shutdown state.
+                return
 
-        reason = 'Soft shutdown requested by OpenStack Nova.'
-        (ret_val, ) = shutdown_component[0].InitiateShutdown(Force=False,
-                                                             Reason=reason)
-        self._jobutils.check_ret_val(ret_val, None)
+            reason = 'Soft shutdown requested by OpenStack Nova.'
+            (ret_val, ) = shutdown_component[0].InitiateShutdown(Force=False,
+                                                                 Reason=reason)
+            self._jobutils.check_ret_val(ret_val, None)
+        except exceptions.x_wmi as ex:
+            # This operation is expected to fail while the instance is booting.
+            # In some cases, InitiateShutdown immediately throws an error
+            # instead of returning an asynchronous job reference.
+            msg = _("Soft shutdown failed. VM name: %s. Error: %s.")
+            raise exceptions.HyperVException(msg % (vm_name, ex))
 
     @_utils.retry_decorator(exceptions=exceptions.WMIJobFailed)
     def set_vm_state(self, vm_name, req_state):