[virt-tools-list] [PATCH] Use node device lifecycle events

[Cole Robinson]

Please add something like this to the commit message body:

  API will be available in upcoming libvirt 2.2.0

On 08/08/2016 03:41 PM, Jovanka Gulicoska wrote:
> ---
>  virtManager/connection.py | 37 +++++++++++++++++++++++++++++++++++++
>  virtManager/nodedev.py    |  3 +++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/virtManager/connection.py b/virtManager/connection.py
> index 5ca8786..97a6d19 100644
> --- a/virtManager/connection.py
> +++ b/virtManager/connection.py
> @@ -215,6 +215,8 @@ class vmmConnection(vmmGObject):
>          self._network_cb_ids = []
>          self.using_storage_pool_events = False
>          self._storage_pool_cb_ids = []
> +        self.using_node_device_events = False
> +        self._node_device_cb_ids = []
>  
>          self._xml_flags = {}
>  
> @@ -796,6 +798,22 @@ class vmmConnection(vmmGObject):
>          else:
>              self.schedule_priority_tick(pollpool=True, force=True)
>  
> +    def _node_device_lifecycle_event(self, conn, dev,
> +                                     event, reason, userdata):
> +        ignore = conn
> +        ignore = userdata
> +
> +        name = dev.name()
> +        logging.debug("node device lifecycle event: device=%s event=%s "
> +            "reason=%s", name, event, reason)
> +
> +        obj = self.get_nodedev(name)
> +
> +        if obj:
> +            self.idle_add(obj.recache_from_event_loop)
> +        else:
> +            self.schedule_priority_tick(pollnodedev=True, force=True)
> +

Since these nodedev events are only when a device is added or removed, we want
to unconditionally repoll the whole netdev list, and the
recache_from_event_loop bit is redundant and should be removed. The recache
logic will be used when UPDATE support is added though, but in a different
function

>      def _add_conn_events(self):
>          if not self.check_support(support.SUPPORT_CONN_WORKING_XEN_EVENTS):
>              return
> @@ -866,6 +884,20 @@ class vmmConnection(vmmGObject):
>              self.using_storage_pool_events = False
>              logging.debug("Error registering storage pool events: %s", e)
>  
> +        try:
> +            if FORCE_DISABLE_EVENTS:
> +                raise RuntimeError("FORCE_DISABLE_EVENTS = True")
> +
> +            eventid = getattr(libvirt, "VIR_NODE_DEVICE_EVENT_ID_LIFECYCLE", 0)
> +            self._node_device_cb_ids.append(
> +                self.get_backend().nodeDeviceEventRegisterAny(
> +                None, eventid, self._node_device_lifecycle_event, None))
> +            self.using_node_device_events = True
> +            logging.debug("Using node device events")
> +        except Exception, e:
> +            self.using_network_events = False
> +            logging.debug("Error registering node device events: %s", e)
> +
>  
>      ######################################
>      # Connection closing/opening methods #
> @@ -888,6 +920,8 @@ class vmmConnection(vmmGObject):
>                      self._backend.networkEventDeregisterAny(eid)
>                  for eid in self._storage_pool_cb_ids:
>                      self._backend.storagePoolEventDeregisterAny(eid)
> +                for eid in self._node_device_cb_ids:
> +                    self._backend.nodeDeviceEventDeregisterAny(eid)
>          except:
>              logging.debug("Failed to deregister events in conn cleanup",
>                  exc_info=True)
> @@ -895,6 +929,7 @@ class vmmConnection(vmmGObject):
>              self._domain_cb_ids = []
>              self._network_cb_ids = []
>              self._storage_pool_cb_ids = []
> +            self._node_device_cb_ids = []
>  
>          self._backend.close()
>          self._stats = []
> @@ -1227,6 +1262,8 @@ class vmmConnection(vmmGObject):
>              pollnet = False
>          if self.using_storage_pool_events and not force:
>              pollpool = False
> +        if self.using_node_device_events and not force:
> +            pollnodedev = False
>  
>          self._hostinfo = self._backend.getInfo()
>  
> diff --git a/virtManager/nodedev.py b/virtManager/nodedev.py
> index 4046ff0..af10e8d 100644
> --- a/virtManager/nodedev.py
> +++ b/virtManager/nodedev.py
> @@ -44,9 +44,12 @@ class vmmNodeDevice(vmmLibvirtObject):
>          return self.get_connkey()
>      def is_active(self):
>          return True
> +    def _using_events(self):
> +        return self.conn.using_node_device_events
>  
>      def tick(self, stats_update=True):
>          # Deliberately empty
>          ignore = stats_update
>      def _init_libvirt_state(self):
> +        self.tick()
>          self.ensure_latest_xml()
> 

I don't think this self.tick() bit does anything and can be dropped

Otherwise looks good!

Thanks,
Cole