How to add timeout to Deferred from Twisted's deferToThread API?

Question

from twisted.internet import reactor
from twisted.internet import threads
from twisted.internet import defer
import time

def worker(arg):
    print 'Hello world'
     time.sleep(10)
    return 1

def run():
    print 'Starting workers'
    l = []
    for x in range(2):
        l.append(threads.deferToThread(worker, x))
    return defer.DeferredList(l)

def res(results):
    print results
    reactor.stop()

d = run()
d.addCallback(res)
reactor.run()

How to stop workers by timeout ?

Answer 1

Threads cannot be interrupted unless they cooperate with you. time.sleep(10) is not going to cooperate, so I don't think you can interrupt this worker. If you have another kind of worker that has several discrete phases, or operates in a loop over some tasks, then you can do something like this:

def worker(stop, jobs):
    for j in jobs:
        if stop:
            break
        j.do()

stop = []
d = deferToThread(worker)

# This will make the list eval to true and break out of the loop.
stop.append(None)

This isn't Twisted specific, either. This is just how threads work in Python.