[SIAv2] capabilities

[Patrick Dowler]

I have been working on editing the SIAv2 draft, mainly splitting it up 
into WD-SIA-2.0 which contains the query and metadata capabilities and 
the WD-AccessData-1.0 which contains sync and async data access 
capabilities (the latter two could be thought of as getData and 
stageData respectively). In making these capablities/resource consistent 
with DALI, I ran into a few small-ish issues that need some input. This 
is to start that open discussion...


1. I defined the {query} capability as a DAI-sync resource that accepts 
a certain set of params (REQUEST, RESPONSEFORMAT, MAXREC, plus the 
actual query params). Does anyone feel that we also need a DALI-async 
query resource for these simple parameter-based queries? (see *)

2. The {metadata} capability returns the complete metadata (as defined 
by ImageDM) for a single observation discovered via {query} and could 
also be used with a TAP/ObsCore query response. I have assumed this 
resource is also a DALI-sync resource and that async is not needed here.

3. As written, it would be allowed for these two capabilities to be the 
same resource (different values of REQUEST) or two different resources 
(each supporting their specific value of REQUEST). That is more flexible 
than previous SIAv2 drafts, in which only the REQUEST value differed.

Comments?

* One motivation for async query might be that if you also want to 
redirect the response to some other destination (eg. write response to 
some vospace location) then that naturally works much better in an async 
job.

-- 

Patrick Dowler
Canadian Astronomy Data Centre
National Research Council Canada
5071 West Saanich Road
Victoria, BC V9A 2L9

250-363-0044 (office) 250-363-0045 (fax)