libvirt: Define and emit DeviceRemovedEvent and DeviceRemovalFailedEvent

This patch registers for VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED and
VIR_DOMAIN_EVENT_ID_DEVICE_REMOVAL_FAILED libvirt events and transforms
them to nova virt events.

This patch also extends the libvirt driver to have a driver specific
event handling function for these events instead of using the generic
virt driver event handler that passes all the existing lifecycle events
up to the compute manager.

This is part of the longer series trying to transform the existing
device detach handling to use libvirt events.

Co-Authored-By: Lee Yarwood <lyarwood@redhat.com>
Related-Bug: #1882521
Change-Id: I92eb27b710f16d69cf003712431fe225a014c3a8

1 files changed, 42 insertions, 5 deletions

diff --git a/nova/virt/libvirt/host.py b/nova/virt/libvirt/host.py
index 586d2c5fdc..3cec733652 100644
--- a/nova/virt/libvirt/host.py
+++ b/nova/virt/libvirt/host.py
@@ -56,6 +56,7 @@ from nova import rpc
 from nova import utils
 from nova.virt import event as virtevent
 from nova.virt.libvirt import config as vconfig
+from nova.virt.libvirt import event as libvirtevent
 from nova.virt.libvirt import guest as libvirt_guest
 from nova.virt.libvirt import migration as libvirt_migrate
 from nova.virt.libvirt import utils as libvirt_utils
@@ -197,6 +198,32 @@ class Host(object):
             self._conn_event_handler_queue.task_done()
 
     @staticmethod
+    def _event_device_removed_callback(conn, dom, dev, opaque):
+        """Receives device removed events from libvirt.
+
+        NB: this method is executing in a native thread, not
+        an eventlet coroutine. It can only invoke other libvirt
+        APIs, or use self._queue_event(). Any use of logging APIs
+        in particular is forbidden.
+        """
+        self = opaque
+        uuid = dom.UUIDString()
+        self._queue_event(libvirtevent.DeviceRemovedEvent(uuid, dev))
+
+    @staticmethod
+    def _event_device_removal_failed_callback(conn, dom, dev, opaque):
+        """Receives device removed events from libvirt.
+
+        NB: this method is executing in a native thread, not
+        an eventlet coroutine. It can only invoke other libvirt
+        APIs, or use self._queue_event(). Any use of logging APIs
+        in particular is forbidden.
+        """
+        self = opaque
+        uuid = dom.UUIDString()
+        self._queue_event(libvirtevent.DeviceRemovalFailedEvent(uuid, dev))
+
+    @staticmethod
     def _event_lifecycle_callback(conn, dom, event, detail, opaque):
         """Receives lifecycle events from libvirt.
 
@@ -330,9 +357,9 @@ class Host(object):
         while not self._event_queue.empty():
             try:
                 event_type = ty.Union[
-                    virtevent.LifecycleEvent, ty.Mapping[str, ty.Any]]
+                    virtevent.InstanceEvent, ty.Mapping[str, ty.Any]]
                 event: event_type = self._event_queue.get(block=False)
-                if isinstance(event, virtevent.LifecycleEvent):
+                if issubclass(type(event), virtevent.InstanceEvent):
                     # call possibly with delay
                     self._event_emit_delayed(event)
 
@@ -366,10 +393,10 @@ class Host(object):
         if event.uuid in self._events_delayed.keys():
             self._events_delayed[event.uuid].cancel()
             self._events_delayed.pop(event.uuid, None)
-            LOG.debug("Removed pending event for %s due to "
-                      "lifecycle event", event.uuid)
+            LOG.debug("Removed pending event for %s due to event", event.uuid)
 
-        if event.transition == virtevent.EVENT_LIFECYCLE_STOPPED:
+        if (isinstance(event, virtevent.LifecycleEvent) and
+            event.transition == virtevent.EVENT_LIFECYCLE_STOPPED):
             # Delay STOPPED event, as they may be followed by a STARTED
             # event in case the instance is rebooting
             id_ = greenthread.spawn_after(self._lifecycle_delay,
@@ -443,6 +470,16 @@ class Host(object):
                 libvirt.VIR_DOMAIN_EVENT_ID_LIFECYCLE,
                 self._event_lifecycle_callback,
                 self)
+            wrapped_conn.domainEventRegisterAny(
+                None,
+                libvirt.VIR_DOMAIN_EVENT_ID_DEVICE_REMOVED,
+                self._event_device_removed_callback,
+                self)
+            wrapped_conn.domainEventRegisterAny(
+                None,
+                libvirt.VIR_DOMAIN_EVENT_ID_DEVICE_REMOVAL_FAILED,
+                self._event_device_removal_failed_callback,
+                self)
         except Exception as e:
             LOG.warning("URI %(uri)s does not support events: %(error)s",
                         {'uri': self._uri, 'error': e})