Enable mypy on libvirt/guest.py

This patch fixes couple of thing that is needed to run mypy

* fixed a wrong type hint in LibvirtDriver._add_vtpm_device,
  _configure_guest_by_virt_type, and _conf_non_lxc signature
* fixed a local variable type hint in LibvirtDriver._create_guest_with_network
* added an assert to _create_guest_with_network as the guest local
  variable can be None if we get eventlet.timeout.Timeout and
  CONF.vif_plugging_is_fatal is False.

Change-Id: I42c579531bac61063a381598094720271364ec92
(cherry picked from commit c17f1e1)

Author: Balazs Gibizer

mypy-files.txt

@@ -9,5 +9,6 @@ nova/virt/libvirt/machine_type_utils.py
 nova/virt/libvirt/__init__.py
 nova/virt/libvirt/driver.py
 nova/virt/libvirt/event.py
+nova/virt/libvirt/guest.py
 nova/virt/libvirt/host.py
 nova/virt/libvirt/utils.py

nova/virt/libvirt/driver.py

@@ -6032,7 +6032,7 @@ def _add_virtio_serial_controller(self, guest, instance):
 
     def _add_vtpm_device(
         self,
-        guest: libvirt_guest.Guest,
+        guest: vconfig.LibvirtConfigGuest,
         flavor: 'objects.Flavor',
         instance: 'objects.Instance',
         image_meta: 'objects.ImageMeta',
@@ -6225,7 +6225,7 @@ def _get_supported_perf_events(self):
 
     def _configure_guest_by_virt_type(
         self,
-        guest: libvirt_guest.Guest,
+        guest: vconfig.LibvirtConfigGuest,
         instance: 'objects.Instance',
         image_meta: 'objects.ImageMeta',
         flavor: 'objects.Flavor',
@@ -6327,7 +6327,7 @@ def _configure_guest_by_virt_type(
 
     def _conf_non_lxc(
         self,
-        guest: libvirt_guest.Guest,
+        guest: vconfig.LibvirtConfigGuest,
         root_device_name: str,
         rescue: bool,
         instance: 'objects.Instance',
@@ -7258,7 +7258,7 @@ def _create_guest_with_network(self, context, xml, instance, network_info,
             events = []
 
         pause = bool(events)
-        guest: libvirt_guest.Guest = None
+        guest: ty.Optional[libvirt_guest.Guest] = None
         try:
             with self.virtapi.wait_for_instance_event(
                     instance, events, deadline=timeout,
@@ -7304,6 +7304,7 @@ def _create_guest_with_network(self, context, xml, instance, network_info,
                     cleanup_instance_disks=cleanup_instance_disks)
         # Resume only if domain has been paused
         if pause:
+            assert guest is not None
             guest.resume()
         return guest
 

nova/virt/libvirt/guest.py

@@ -28,6 +28,7 @@
 """
 
 import time
+import typing as ty
 
 from lxml import etree
 from oslo_log import log as logging
@@ -41,7 +42,11 @@
 from nova.virt import hardware
 from nova.virt.libvirt import config as vconfig
 
-libvirt = None
+
+if ty.TYPE_CHECKING:
+    import libvirt
+else:
+    libvirt = None
 
 LOG = logging.getLogger(__name__)