best way to serve wsgi with multiple processes

[Robin Becker]

Graham Dumpleton wrote:
.........
> requests.
> 
> If the work is indeed long running, the backend process would normally
> just acknowledge the request and not wait. The web page would return
> and it would be up to user to then somehow occassionally poll web
> server, manually or by AJAX, to see how progres is going. That is,
> further XML-RPC requests from main server to backend daemon process
> asking about progress.
.......
this is exactly what we do with the long runners. The wsgi (django in our case) 
process can work out how long the process is likely to take and either responds 
directly or offloads the job to an xmrpc server and responds with a page 
containing a token allowing access to the queue server which refreshes 
periodically to determine job status etc etc. When the job finishes the refresh 
request returns the job result and finishes looping. In our case we don't need 
to worry about people abandoning the job since the results are cached and may be 
of use to others (typical case produce brochure containing details of all 
resources in a country or large city). To avoid overload the xmlrpc server is 
only allowed to run 3 active threads from its queue.
-- 
Robin Becker