[Libvir] uuid string format

[Daniel P. Berrange]

On Tue, May 23, 2006 at 12:02:09AM +0200, Karel Zak wrote:
> On Po, kv?? 22, 2006 at 09:52:35 -0400, Daniel Veillard wrote:
> > On Mon, May 22, 2006 at 03:45:04PM +0200, Karel Zak wrote:
> > > 
> > >  Hello,
> > > 
> > >  I've found that we use in our XML dump:
> > > 
> > >   <uuid>%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x</uuid>
> > > 
> > >  it's strange format of the UUID string representation. Is there any
> > >  reason for this format?  I think normal (rfc4122) is format:
> > > 
> > >   "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x"
> > > 
> > >  it means with '-'.
> > 
> >   RFC 4122 is for URN embedding, that's a specific use. We are not following 
> > that syntax anyway since it's not an URN, we really don't need to encode this
> > as an URI, only as an unambiguous ASCII string, and the current format does
> > the job minimally.
> 
>  Well, for example "xm list --long" uses the format with '-' (and
>  xend, filesystems, and ... everywhere). I think it's better follow
>  old manners although we don't need it.

More importantly than tradition - the printable formatting of UUIDs is quite 
often visible to humans, where the chunked formatting greatly increases
readability - one can much more easily compare two UUIDs in chunked encoding.
So, given its a mere 4 extra characters I think its definitely worthwhile.

>  I've commited virDomainGetUUIDString() and virDomainLookupByUUIDString() 
>  functions and the virsh command supports domain look up by UUID now.
>  
>  All these changes use '-' format ;-) It's nothing important, but I
>  think it's better support conversion from/to UUID string in the
>  library rather than duplicate this code in every libvirt application.
>  Now we use UUID in gnome-virt-manager (+ in dbus API), virsh and my
>  plan is use it also in gnome-applet-vm.

Great - as you say I'd already had to written such code in both the Perl
bindings & the gnome-virt-manager application, so this will usefully 
removely that duplication.

Dan.
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