Open Stack

On 11/09/2012 06:26 PM, Mellquist, Peter wrote:
> Each LBaaS offering may differ in its capabilities hence I think they
> need to be advertised as a resource or schema. Without this, a client
> has to do trial and error to find out what is supported which is not
> very  good. IMO, resources would be the easiest.

Agreed that there needs to be an introspective way to advertise
capabilities of the service.

In Nova, there is the /extensions resource which provides descriptors
for the API extensions provided by a particular Nova API server. I think
the same could be done here, but I would not go for the multiple
resources route. I would go with a simple schema descriptor instead.

In Glance's v2 API, we threw around a number of ideas around how to
return this kind of metadata, and settled on JSONSchema, which can be
queried quite easily to determine supported features/capabilities [1]
[2]. Of course, the same can be done with XMLSchema if you want to go
that route.

Best,
-jay

[1] https://github.com/openstack/glance/blob/master/glance/schema.py
[2]
https://github.com/openstack/glance/blob/master/glance/api/v2/images.py#L688