0MQ: The Intelligent Transport Layer

[Roy Williams]

On 12/20/11 3:51 PM, Matthew Graham wrote:
> Hi,
>
> Agreed but considerations should include:
>
> - Is there conceptually anything wrong with the existing
> infrastructure?

There are protocols in use for transporting VOEvents or other formats.
-- Some are point to point:
       http POST, email a la MPC, GCN circulars.
-- Some are publish-subscribe (pubsub):
       Jabber/XMPP, original GCN socket, VO-GCN broker, Dakota broker.

The 0MQ people say they can do both kinds of message.

> - Is it just a case that the current tools are not good enough and
> no-one has been bothered enough to dedicate some time to sorting this
> out?

I've spent enough time trying to get Jabber/pubsub behaving itself. 
Sending an XML packet (VOEVent) within another XML protocol (Jabber) is 
delicate at best, especially when XML compliance is required.

- What exactly are our use cases for event transport?

Combination of push and pull transport

Push Point-to-point:
-- event goes direct to recipient
-- personal selection, personal feed, handling emails
-- driving remote annotators
-- sender handles identity mgmt

Push Publish-subscribe:
-- following all events from a given stream or substream
-- event travels to server, broadcast to subscribers
-- server handles identity mgmt

Pull:
-- a query is sent to an event repository
-- a set of events is returned


Authoring:
with identity management

Query services
result is a set of events

Replication:
cloning a repository elsewhere


Roy

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