Re: [xmlblaster] distributed cluster protocol

[Michael Atighetchi <matighet at bbn.com>]

Michele, 

is it possible to write a plugin for changing the behavior of a
xmlblaster server after it has matched publications with subscriptions?

I'm in need for this, as I'd like to only send a selective part of
the initially published information to the subscribers, and hence
would like to do post-matching filtering (would be a nice complement
to the PublishFilter plugin, which does pre-matching filtering).

If it's not high on anyones priority list, I might consider
implementing this myself and integrating it into the latest cvs
tree. Any opinions on the prefered design ? 

Michael



On Sat, May 03, 2003 at 11:42:05AM -0400, Michael Atighetchi wrote:
> Hi Michele,
> 
> thanks for the info - this was exactly the level of details I was
> looking for. I'll start working on the PublishFilter plugins next
> week, and will eventually transition the protocol over when mirroring
> becomes available. Do you have a rough idea when this would be ?
> 
> Thanks
> Michael
> 
> 
> 
> 
> On Sat, May 03, 2003 at 03:34:09PM +0200, Michele Laghi wrote:
> > Hi Michael,
> > I guess the cleanest way to do that is to use the clustering framework. 
> > However I think we need Mirroring for that. Unfortunately is Mirroring 
> > not implemented yet.
> > 
> > Meanwhile a solution would be to have a plugin implementing 
> > I_PublishFilter on X:
> > 
> > It would act as a client to A, B and C. In its method intercept it would 
> > publish to these servers and thereby automatically get an acknowledge 
> > from them.
> > 
> > Servers A, B, C have another plugin (implementing I_PublishFilter) which 
> > acts as a client to the own server. In its intercept method they would 
> > publish a PtP message to the client (you have the address of the client 
> > in the MsgUnit) simulating that way the acknowledge to the client.
> > 
> > 
> >       <__________PtP____________________
> >       <__________PtP__________________  '
> > Client <===> Server X<====> Server A--' '
> >                     |<====> Server B----'
> >                     |<====> Server C----
> >       <------PtP------------------------'
> > 
> > Michele
> > 
> > 
> > 
> > Michael Atighetchi wrote:
> > >Xmlblaster team,
> > >
> > >I'm planning on implementating a distributed protocol for pub/sub/and
> > >query on top of xmlblaster, and am wondering which plugin would be
> > >best fitted to do so.
> > >
> > >To give you an example of my procotol, and publish will go to a
> > >server (X). X then acks the message back to
> > >the client, and disseminates the message on to 3 other
> > >servers. Each server will then ack the message back to the client (so
> > >obviously the message has to contain a client endpoint) and to X. The 
> > >client
> > >waits for 3 successful acks, and then terminates the publish method.
> > >
> > >How difficult do you think would it be to implement such a protocol ?
> > >Which plugin would one use ?
> > >I was looking at I_Plugin and I_PublishFilter, but these plugins seem
> > >less to be involved with message routing/handling, which is what I
> > >believe I need.
> > >
> > >
> > >Thanks
> > >Michael
> > >
> > >
> > 
> > 
> 

-- 
matighet at bbn.com   BBN Technologies