[virt-tools-list] [virt-manager][PATCH v3] Add delete VM option in console viewer.

[Leonardo Augusto Guimarães Garcia]

On 06/17/2013 02:06 PM, Leonardo Garcia wrote:
> diff --git a/virtManager/console.py b/virtManager/console.py
> index b9186ce..001318e 100644
> --- a/virtManager/console.py
> +++ b/virtManager/console.py
> @@ -651,7 +651,10 @@ class vmmConsolePages(vmmGObjectUI):
>           self.page_changed()
>
>       def is_visible(self):
> -        return self.topwin.get_visible()
> +        if self.topwin:
> +            return self.topwin.get_visible()
> +        else:
> +            return False
>
>       def _cleanup(self):
>           self.vm = None
> @@ -892,6 +895,9 @@ class vmmConsolePages(vmmGObjectUI):
>       ##########################
>
>       def view_vm_status(self):
> +        if not self.vm:
> +            # window has been closed and no pages to update are available.
> +            return
>           status = self.vm.status()
>           if status == libvirt.VIR_DOMAIN_SHUTOFF:
>               self.activate_unavailable_page(_("Guest not running"))
> @@ -900,7 +906,6 @@ class vmmConsolePages(vmmGObjectUI):
>                   self.activate_unavailable_page(_("Guest has crashed"))
>
>       def close_viewer(self):
> -        viewport = self.widget("console-gfx-viewport")
>           if self.viewer is None:
>               return
>
> @@ -908,6 +913,7 @@ class vmmConsolePages(vmmGObjectUI):
>           self.viewer = None
>           w = v.display
>
> +        viewport = self.widget("console-gfx-viewport")
>           if w and w in viewport.get_children():
>               viewport.remove(w)
As I think this part of the patch proposal will rise some questions, let 
me try to explain why this is needed.

Again, this is a race condition with the fact that the console viewer 
will be destroyed when the running VM is deleted.

When the VM is deleted, we have: vmmEngine._do_vm_removed -> 
vmmDetails.close -> vmmConsolePages.close_viewer.

However, at some point in time, a call to 
SpiceViewer._main_channel_event_cb will be queued by the channel-event 
signal, and this callback will be executed after the vmmDetails has 
already closed the viewer. In this situation:

SpiceViewer._main_channel_event_cb -> vmmConsolePages.disconnected -> 
vmmConsolePages.close_viewer

So, we need some extra code to make sure that the call to close_viewer 
is successful when the viewer does not exist anymore.

I initially thought this was being caused by the fact that the 
channel-event signal is being listened with connect_after and was being 
handled too late. But even after using GObject.connect I was still 
hitting this error. So I think the event from the spice protocol is 
hitting the application after the vmmDetails has been closed.

Best regards,

Leonardo Garcia