[Twisted-Python] Question about processes in python

Phil Mayers p.mayers at imperial.ac.uk
Mon Apr 12 11:49:54 EDT 2010

On 04/12/2010 04:39 PM, Jason J. W. Williams wrote:
> Haven't had any issues yet. Twisted imports occur inside the process
> function. The app was originally written as a purely blocking
> multiprocessing app and rewritten to use Twisted inside the
> sub-processes. It's passed all automated and hand tests without an
> issue. Is there a reason importing Twisted inside sub-process should
> not work?

When I last looked at it, multiprocessing did awful things like fork'ing 
and not re-execing the interpreter in the child process, which seemed 
like an absolute disaster waiting to happen, for many types of objects 
which the child process inherits. Does it still do that?

I guess what you're doing will work though, In that setup, where the 
multiprocessing code is the absolute first thing you call, you're 
essentially using it as a helper to fork off the child process & setup 
the communication pipes (see the example I just posted for a more 
explicit example).

There's the issue that any multiprocess code which writes to the pipes 
(or whatever) used for sending results will block (and block the 
reactor) of course.

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