Thanks, how embarassing... I suggest adding it to the "using threads" howto (I'd do it myself if I knew how). Another idea: make an asynchronous file-handling module that wraps Python's file IO with something that has a deferred-oriented interface. Is there already something like that too?
Joe
--- Jp Calderone exarkun@divmod.com wrote:
On Wed, 27 Apr 2005 05:49:01 -0700 (PDT), Joachim Boomberschloss boomberschloss@yahoo.com wrote:
Hi all,
I am just wondering: from the Twisted how-tos, it appears that doing anything that could possibly
take
arbitrarily long to execute should not be done in
the
reactor's main thread; i.e. it should be done using
an
asynchronous library (such as Twisted's network communication facilities), or in a different
thread,
using the reactor's thread pool.
So it would seem that many things that may be considered "primitive" in Python, such as file IO, require some kind of patching if they are to be immediately usable by a Twisted application. I came
up
with the following solution, which enables calling
any
function in a different thread with a deferred interface; I just wanted to make sure that I'm not completely missing some point:
def deferToThread(func, *args, **kargs): """executes the given function in a thread, and passes the return value to the deferred we
return"""
d = defer.Deferred() reactor.callInThread(_calledInThread, d, func,
*args,
**kargs) return d
def _calledInThread(d, func, *args, **kargs): try: retval = func(*args, **kargs) except Exception, x: reactor.callFromThread(d.errback, x) else: reactor.callFromThread(d.callback, retval)
Looks like you've got a pretty firm understanding. The one thing you did miss is the twisted.internet.threads module, which provides the deferToThread function.
Jp
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