[virt-tools-list] [PATCH virt-manager v4] Add inspection to virt-manager

[Daniel P. Berrange]

On Tue, Jul 19, 2011 at 10:17:02AM -0400, Cole Robinson wrote:
> On 07/19/2011 03:49 AM, Richard W.M. Jones wrote:
> > On Mon, Jul 18, 2011 at 05:41:00PM -0400, Cole Robinson wrote:
> >> On 07/18/2011 02:53 PM, Richard W.M. Jones wrote:
> >>> This updates 1/4 with the fixes you suggested.  Also, all check-pylint
> >>> warnings and errors have been fixed.
> >>>
> >>> Rich.
> >>>
> >>
> >> Thanks! Pushed the series.
> > 
> > In reply to your comment on IRC:
> > 
> > crobinso> rjones: so in the default usage of virt-manager in fedora,
> >                   the guest inspection probably won't work since we
> >                   save disk images in /var/lib/libvirt/images/, which
> >                   regular user doesn't have access to.
> > crobinso> rjones: that's not entirely clear from feature page.
> > crobinso> rjones: I'm thinking of adding a disk path access check in
> >                   the inspection thread, to avoid flooding the logs
> >                   with errors if we can't even read the disk
> >                   image. that should be safe to do?
> > 
> > I always run virt-manager as root (or from sudo) so this hasn't been
> > an issue.  What user does virt-manager run as normally?
> >
> 
> I think most common usage is just running virt-manager as the logged in
> user, using policykit to authenticate the libvirt connection so the rest
> of the app doesn't have root privs.
> 
> > AFAICT if there's no access to the disks, then the call to either
> > g.add_drive_opts or g.launch will throw an exception.  But the
> > inspection._vmseen hash will mean this will only happen once per
> > domain per run of virt-manager.
> > 
> > On an unrelated note: I think we need to cache inspection between runs
> > of virt-manager.  Does virt-manager currently store permanent state (I
> > assume it must do - ie. list of connections), and where?
> > 
> 
> We store config like that in gconf, though I don't think sticking
> largish data like list of applications or a png in there is a good idea.
> hostname + os info could be cached, though ideally the latter would be
> stored in libvirt XML at some point.

Agreed, it would be desirable to cache the PNGs in $HOME/.virt-manager
though, perhaps as

  $HOME/.virt-manager/icons/$CONN_URI/$DOMAIN_UUID

To avoid growing without bound, probably want to have virt-manager
purge files in that directory on startup, if the PNG is older than
3 months and the associated connection or domain no longer exists.
ie don't immediately purge them, since a user might later re-add a
connection or re-create a VM.

Another thought though is that we've also got some work going on a
little plugin for gnome-shell to capture & display screenshots of
VMs. It might be nice for virt-manager to take advantage of this
too, while also the shell plugin might like the icon image. So
perhaps we should declare a standard location for storing assets
related to a VM, which are expensive to extract/fetch.

 $HOME/.local/libvirt/$CONN_URI/$DOMAIN_UUID/screenshot.png
 $HOME/.local/libvirt/$CONN_URI/$DOMAIN_UUID/icon.png
 $HOME/.local/libvirt/$CONN_URI/$DOMAIN_UUID/osinfo.json

or something like that

Daniel
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