[fedora-virt] Re: [et-mgmt-tools] RFC: libosinfo: Library for virt OS/distro metadata 3

[Daniel P. Berrange]

On Mon, Jun 15, 2009 at 07:16:56AM -0400, John Levon wrote:
> On Sun, Jun 14, 2009 at 06:50:02PM -0400, Cole Robinson wrote:
> 
> > git clone http://fedorapeople.org/~crobinso/osinfo/.git
> 
> I'm not convinced by the "arbitrary hierarchy" thing: I just don't see
> how that could possibly be useful. Surely it's either an entirely flat
> namespace, or a shallow structured one like you have.
> 
> The flat namespace would be a set of keys and multiple values for each
> key. One value would be "os type" (linux, windows, etc.). You'd most
> likely have a "generic" entry still for fallback.

I think this is the way to go. Flat list + properties, and allow apps
to build hiearchies on the fly as needed, based off properties.

> An alternative is to represent the hierarchy in the UNIX way, via the
> filesystem:
> 
> /var/lib/osinfo/
> /var/lib/osinfo/linux/info.xml
> /var/lib/osinfo/linux/fedora/info.xml
> /var/lib/osinfo/linux/fedora/8/info.xml
> 
> The fallback is pretty obvious then. Maybe it's over the top. The idea
> of a single delivered XML file that users edit does trouble me though.
> Maybe we at least have two files, one for customisations.

A single XML file would be pretty horrible for package upgrades.
With a flat list we can have 1 XML file per distro. If we allow
multiple search paths for XML files, we can have the stadnard
shipped ones in /usr/share/osinfo, and customized ones in /etc/osinfo
the latter overriding (or inheriting from) the former.


> > - How should we handle derivatives like Scientific Linux + CentOS: should we
> >   expect users to understand they are based on RHEL, or give them explicit
> >   IDs?
> 
> Explicit IDs. You'd be surprised.

Download/install URLs already require that we do separate IDs :-)


Daniel
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