Re: [libvirt] Generic processing of xml data
On 02/01/2012 07:01 AM, Hendrik Schwartke wrote:
There are some changes made to the conf code to handle some new tags
like <title> or to add some "metadata" to a domain description in the
last days.
I'm wondering if there is a more generic (read better) way to handle
those extra data in xml config elements.
I think it would be far more reasonable to use xml namespaces to enable
libvirt to differentiate between config options which it has to process
and data which are unknown to libvirt and thus are only stored without
any further processing.
That's precisely what we have already started implementing. We added
the <metadata> element that takes one sub-element per namespace for use
by however the application sees fit:
https://www.redhat.com/archives/libvir-list/2012-January/msg00943.html
and have a pending API to allow runtime manipulation of that metadata:
https://www.redhat.com/archives/libvir-list/2012-February/msg00032.html
This distinction could then by easily used for expansions like the
<title>-tag, to store the x- and y-position of a guest in a graphical
visualization of virtual networks, to add some names of administrators
which are responsible for the guests, to add some hints to interfaces
concerning quality of service, etc...
I don't know how complex such in implementation would be but I think it
would be worth the effort.
Right now, the only missing part is wiring up the proposed API from
Peter's series to actually modify the XML from Zeeshan's patch, if you'd
like to help with that.
--
Eric Blake eblake(a)redhat.com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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