perfsonar development work

[Maciej Glowiak <>]

Hi Nina,

I have been thinking on all of these issues for a long time :)

Nina Jeliazkova wrote:
> Hello all,
>
> Trying to use lookup service in PerfsonarUI, here is what is not clear to me:
>
> 1) Is it mandatory for a service to register information other than pure
> information about service (URL, name), e.g. interfaces?

No. It's undefined in fact. We defined a couple of attributes such as 
name, URL, description and type. There are now some other fields 
(organization, administrator, etc.). But data elements may contain 
anything. Now, for MA services we publish all interfaces, but using 
multi LS there may be aggregated data. That's quite a big problem for 
client applications because it should know what may be found inside 
service response. So, there is no good answer for your question. You may 
make use of data elements inside Lookup Information, but it is still not 
mandatory information.

> 2)Is there any way to discover schema supported by the service (for
> PerfsonarUI to provide backward compatibility, like current MA.conf settings).
>  I understood supported event type can be figured out from interfaces
> registration, but what about services that don't register these? Additionally,
> is it possible for interfaces within same service to support different event
> types?

No. I was thinking on adding attribute to metadata element, such as 
schema-version or something like that (at least service version).

> 3)Is there a way to distinguish between different types of MA services (e.g.
> utilization MA service and Hades service). I saw a suggestion to have subType
> parameter, but not sure it is implemented already or if it will be mandatory.

It's not implemented. There were two solutions: subtype vs. hierarchy of 
types. For example:

   <type>MA</type>
   <subtype>RRD</subtype>

vs.

   <type>ma.rrd</type>

Another concern is that RRD or SQL are actually not MA types. They're 
implementation type, but the real type is "utilization" or "path 
status". Maybe there should be supportedEventTypes? I am not sure what 
is the status of the implementation / usage of them.

> 4)For PerfsonarUI what will be the best approach - contact single
> preconfigured LS, or have a list of LS to send queries? 

Hmm. I'd have the list of several LS-es (but not too many) and first 
send a request to one LS, then if there is no requested data, I'd send 
the request to others... But one LS is also fine.

> I am aware these points have already been discussed, but not sure there is a
> definite answer or it could be it is already explained in some documentation
> I've missed.

They were discussed several times, but still without strong conclusions.

We should finalize the discussion on all of these topics.

best regards

Maciej