Is it ok to spawn threads in a wsgi-application?

Question

To achieve something similar to google app engines \'deferred calls\' (i.e., the request is handled, and afterwards the deferred task is handled), i experimented a little and ca

Answer 1

FWIW, also have a read of:

http://code.google.com/p/modwsgi/wiki/RegisteringCleanupCode

The hooking of actions to close() of iterable is the only way within context of the WSGI specification itself for doing deferred work. That isn't in a separate thread though and would occur within the context of the actual request, albeit after the response is supposed to have been flushed back to the client. Thus your deferred action will consume that request thread until the work is complete and so that request thread would not be able to handle other requests until then.

In general, if you do use background threads, there is no guarantee that any hosting mechanism would wait until those background threads complete before shutting process down. In fact, can't even think of any standard deployment mechanism which does wait. There isn't really even a guarantee that atexit handlers will be called on process shutdown, something that the referenced documentation also briefly talks about.