Re: RFC for Source Discovery

Tom Doust

I have some feedback about the RFC for OpenMAMA Source Discovery page:

I’m pretty much in agreement with delivering the source descriptions and notification encoded in MAMA messages, it significantly reduces the work required to deliver an implementation and also simplifies things for application writers.

However, I’d like to suggest that rather than build a new API around a notional “source discovery object” as the RFC suggests, we simply make requests on the existing market data subscription API and differentiate by specifying a “special” source name (similar to how dictionary subscriptions are made ) This will work for both initial “discovered source” messages and updates to source status. This approach works well enough in the Tick42 TREP bridge. The main benefit of this approach is that in its simplest form it requires NO code to be written in the mama infrastructure and avoids having to replicate the API across each of the language bindings.

All the additional code devolves to the bridge implementation – this has to be written anyway. The special source name can be either fixed, hard coded in some way, or configurable through the file. Although we would probably all agree as programmers it should be configurable, I can’t really think of a strong reason why J

I think that defining the fields as properties as indicated is necessary as it effectively defines the message schema but there are a couple of potential issues that are not covered by the RFC

  • Fid clashes. If the fids are defined as properties by the mama infrastructure there is a risk that they will overlap with fids defined in a dictionary posted by a bridge. This may not necessarily be a problem as the context may resolve any such clashes but nevertheless it might be worth exploring ways to avoid this
  • I think the fields need to be typed. Mostly they will be strings but some might be bool or int. This requires another property for each.


Is it possible to attribute a source with a data dictionary? I suspect that currently the assumptions made about field names in some of the MAMDA code effectively limit to a single data dictionary. This is an area that needs to be carefully explored and potentially tidied up.

Best regards


Tom Doust


TOM DOUST | Head of  Consultancy                                                                                             


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From: openmama-dev-bounces@... [mailto:openmama-dev-bounces@...] On Behalf Of Frank Quinn
Sent: 13 September 2017 11:53
To: openmama-dev <openmama-dev@...>
Subject: [Openmama-dev] RFC for Source Discovery


Hi Folks,


We have a new RFC contributed by Arcontech to cover the upcoming Source Discovery functionality. Thanks very much to the Arcontech folks for taking the time to put this together.


You can find it listed here:



As a reminder of the RFC process and how to get involved, I'll refer you all to:



Pay particular attention to the most constructive ways to provide feedback:


As per our process, we will leave this RFC open for a period of 2 weeks, after which point if there are no major concerns, the RFC design will be considered approved and work can begin.




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