TAP information schema

[Guy Rixon]

Doug,

the vos:// URI does not give the service endpoint directly. You need to look
it up in the registry or get it by some other means, like maybe a shared
catalogue.

This is deliberate. We want the data-node URIs to be extremely stable, s.t.
the data may be rearchived by without changing the names. If we embed the
endpoint of the service in the name, then this is impossible.

Further, one can imagine a VOSpace that has multiple endpoints on different
hosts, for fail-over. We can do this in VOSI and in the registry, but it's
hard to embed multiple endpoints in a single URI.

Cheers,
Guy

On Sun, 14 Oct 2007, Doug Tody wrote:

> On Sun, 14 Oct 2007, Guy Rixon wrote:
> > Similarly, a service presented with a vos:// URL knows it's dealing with
> > VOSpace, but it has to go to the registry (or to its cache of registry
> > information) to find out which version.
> >
> > The pattern is that a data URL is either for a data stream or for a service
> > that is a generator of data streams, and the only supported cases of the
> > latter are MySpace and VOSpace. We can't exchaneg data with an arbitrary SOAPm
> > or REST service unless we know its protocol.
>
> So does the vos:// URI tell us the VOSpace service endpoint directly,
> or do we have to involve the registry to resolve this?
>
> Also, it should be possible to query the VOSpace directly (via
> getCapabilities or whatever, if not now in a later version) to find
> out what version of the VOSpace protocol it supports.
>
> Sevices can be used both in a Grid/Internet-based mode and locally;
> it should not be required to involve a remote Internet-based registry
> for basic operation of a service.
>
> 	- Doug
>

Guy Rixon 				        gtr at ast.cam.ac.uk
Institute of Astronomy   	                Tel: +44-1223-337542
Madingley Road, Cambridge, UK, CB3 0HA		Fax: +44-1223-337523