Writing a TTL decorator in Python

Question

Hi,

I'm trying to write a TTL decorator in python. Basically I give it raise an exception if the function doesn't answer in the selected time.

You can find the thead2 snippets on http://sebulba.wikispaces.com/recipe+thread2

from thread2 import Thread

"""  A TTL decorator. """
class Worker(Thread):
    def __init__(self, q, f, args, kvargs):
        Thread.__init__(self)

        self.q = q
        self.f = f
        self.args = args
        self.kvargs = kvargs

    def run(self,):
        try:
            res = (True, self.f(*self.args, **self.kvargs))
            self.q.put(res)
        except Exception, e:
            self.q.put((False, e))

class Referee(Thread):
    def __init__(self,q, ttl,exception_factory):
        Thread.__init__(self)

        self.exception_factory=exception_factory    
        self.q=q
        self.ttl=ttl

    def run(self):
        time.sleep(self.ttl)
        res = (False, self.exception_factory())
        self.q.put(res)

def raise_if_too_long(ttl, exception_factory=lambda :RuntimeError("Timeout")):
    def raise_if_too_long_aux(f):
        def ritl(*args,**kvargs):
            q = Queue.Queue(2)

            referee = Referee(q, ttl, exception_factory)
            worker = Worker(q,f,args,kvargs)

            worker.start()
            referee.start()

            (valid, res)= q.get(1)

            q.task_done()

            referee.terminate()
            worker.terminate()

            if valid:
                return res
            else:
                raise res

        return ritl

    return raise_if_too_long_aux

However, I get some pretty bad result. It seems like sometimes the function is returning alright yet the decorator doesn't return until the TTL is reached and the error raises.

Do you see something wrong in this code? Is there a common way/library to write function with a TTL in python?