[Twisted-Python] Advise for heavy concurrency

[Alec Matusis]

> Because it is not a supported use of the API.  Twisted APIs, unless
> other-
> wise documented, are not thread safe and can only be called from the
> thread
> in which the reactor is running.

Then I do not understand when it is safe to use 

t.i.threads.deferToThread(f, clients) ?

I was thinking of calling this from the main reactor thread, where f is

def f(clients):
    for client in clients:
        client.protocol.transport.write('hello')


This function would not even have a deferred attached to it. 
Is the point that it's not thread-safe to have Twisted API calls
inside the function f?

> -----Original Message-----
> From: twisted-python-bounces at twistedmatrix.com [mailto:twisted-python-
> bounces at twistedmatrix.com] On Behalf Of Jean-Paul Calderone
> Sent: Saturday, December 01, 2007 10:25 PM
> To: Twisted general discussion
> Subject: RE: [Twisted-Python] Advise for heavy concurrency
> 
> On Sat, 1 Dec 2007 19:40:28 -0800, Alec Matusis <matusis at yahoo.com>
> wrote:
> >> > You cannot call any Twisted functions from a thread, with the
> >> > exception
> >>                                         ^^^^^^^^^^^^^ Er, I guess I
> >> should have worded this more carefully. What I meant is: you cannot
> >> call any Twisted functions from a different thread to the one the
> >> reactor is running in, which includes any thread created with
> >> deferToThread.
> >>
> >> > of callFromThread; so this would probably be pretty pointless.
> >
> >
> >I am not sure I understood this: suppose my message sending loop
> simply
> >loops over client protocol instances and calls
> >transport.write(some_message)
> >
> >Why cannot I call this loop in a thread from the main reactor loop
> >to have it non-blocking in case this sending loop is giant (over 1000s
> of clients)?
> 
> Because it is not a supported use of the API.  Twisted APIs, unless
> other-
> wise documented, are not thread safe and can only be called from the
> thread
> in which the reactor is running.
> 
> Jean-Paul
> 
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