Rendezvous and WebObjects
Rendezvous and WebObjects
- Subject: Rendezvous and WebObjects
- From: David Aspinall <email@hidden>
- Date: Wed, 19 May 2004 13:02:22 -0400
For the past year we have been using openJms for change notification,
but we are not 100% happy with the results. I wont go into the issues
here, but I am experimenting with options.
My question is: does anyone have good or bad experiences using
Rendezvous (ZeroConf) with WebObjects applications?
My proposed uses are:
- change notification - as each app launches, it will look for a
Rendezvous/changeNotification service and if one is not found, the it
will register itself as the coordinator. If the coordinator dies the
remaining apps will attempt to promote themselves as the coordinator
and the winner will assume that role. This makes (I hope) for a robust
but non-deterministic change service.
- background processing coordination - we have a financial forecast
model that can take up to 3 seconds (assuming all data is in memory) to
process. currently we have a "forecaster" application listening for
relevant change notification (new balance, new investment, changed
retirement date...) and auto forecasting as required. This works
because often these values change but the user is not actually viewing
the forecast at this moment so a delay in forecast update is
acceptable. The downside is that if 2 "forecast" applications are
running, both will attempt to forecast the same user, which is a waste.
I propose using Rendezvous to coordinate these actions so only one
application will perform the required activity (can be expanded to the
general case for other scheduled processes).
- background report generation - if the advisor wishes to generate
custom reports for large number of clients (yes they have been known to
generate upwards of 500 letters at a time), using Rendezvous and web
services we could distribute the processing load among multiple
applications. Here I would also like to track the number of activities
already running on each application and balance them appropriately.
Also some activities take longer than other so each activity would also
need a weight. Completed reports can either be returned using web
services, or automatically stored in the database as MIME content.
(with multiple app servers storing on the filesystem is not sufficient,
or it would be if our clients had robust SANS, but they do not)
- centralized logging - with multiple app servers, logs are generate on
multiple filesystems and are painful to locate and review when problems
occur. Similar to change notification a log coordinator could receive
all log output and organize the data appropriately. Or each
application could provide log retrieval services and the "admin"
application could then search and consolidate log reporting for each
application.
There is a fair amount or R+D for all of this (fortunately there is a
good OpenSource java implementation of mDNS) so most of the work is on
the coordination and distribution side. I just wondered if anyone else
had or was working along these lines. I might be able to convince my
boss that this would be a good collaborative Opensource project we
could contribute to ... anyone?
---
email@hidden
(416) 513-9524 x263
Ticoon Technology Inc.
56 The Esplanade, Suite 404, Toronto, ON, M5E 1A7
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