[ivoa-std/VOEvent] Registry matters (#11)

[Dave Morris]

On 2020-11-03 08:58, Baptiste Cecconi wrote:
> 
> I think it is ok to have "unregistered" streams for prototyping
> purposes. However, if we want to raise the VOEvent standard in the era
> of FAIR science, we need to be able to find metadata from a VOEvent
> using its ID. This implies that the VOEvent stream metadata is
> available somewhere. To me the IVOA Registry is the natural place for
> the IVOA ecosystem. It would be nice to have a Note on how to do this
> another way (other URIs, other registry...)

I agree, but, I think it should be MAY not MUST.

There are many use cases for having private (unregistered) services.

Someone may want to set up a service for propagating events along an 
internal data processing pipeline that is not available to the public.

Someone may want to set up a service for propagating events to a data 
analysis platform that are only intended to be available to users 
running notebooks on a JupyterHub inside that cloud compute platform.

Someone may want to set up a service for propagating events that are 
nothing to do with astronomy.

All of which are possible with a TAP service and still remain standard 
compliant, but they are are not possible with a standards compliant 
VOEvent service because we entangle the event identifier with the 
service registration.

Dis-entangling the event identifier from the service registration is 
likely to be a gradual process, with many changes to the specification.

It would be good if we could make this PR into a step along that path, 
by changing the emphasis of the wording to be IF and MAY rather than 
MUST.

-- Dave

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Dave Morris
Research Software Engineer
Wide Field Astronomy Unit
Institute for Astronomy
University of Edinburgh
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