Hi Doug and co, I've written an Apache module I've called Apache::AppCluster that I would like to propose for publication to CPAN in the Apache::* namespace.
It allows one to use apache and mod_perl as a clustered/distrubited app server spawning remote processes/requests in paralell. It allows you to set up an object locally and then register 'requests' with it. Each request is a function call (and data structure) that will be sent to a remote apache/mod_perl app server via a POST (using freeze/thaw for encoding) and will be executed on that server. The results are returned, decoded and are accessable for each 'request' that was registered with the object using an index. The client module can be used under mod_perl or as standalone. The server component must run under mod_perl as a handler for a <Location> and wont interfere with any other handlers. The cool thing about this is (IMHO) that it uses non-blocking sockets to send off all requests at the same time (well, almost - it sends them off in rapid succession) so all processing on remote 'app servers' happens simultaneously. Results are then collected simultaneously from all sockets as they are received (loops through non-blocking sockets collecting data until all is received or a timeout occurs). When registering requests you specify the remote server and port for each request so you can have 1000 remote methods being called on 100 seperate app servers all processing at the same time and being consolidated on a single front end server within a single object. This was inspired by SOAP, but the difference is that every implementation of SOAP I've come accross uses blocking sockets which is a problem since thread support in Perl is not that great and you can't really use fork() under mod_perl - or at least I've never had the guts to try. So this allows you to do remote method calls on an app server in parralel while still having a single thread of execution in the calling process. The reason I didn't just write a non-blocking version of SOAP is because I want super fast performance, and I've found that SOAP is quite slow on the client and server side. We're using this in-house as part of a web service running on a front end server (apache/mod_perl exposing a SOAP API) that then spawns a bunch of processes on some back-end servers also running apache/mod_perl using Apache::AppCluster. I already have a PAUSE ID and would like to know if I may include this in your namespace - and if there's anything out there like this already. If this sounds useful, let me know and I'll package it up and either upload it or send you the url for review. thanks, Mark Maunder.
