Question

I am new to twisted and python, I am reading twisted python.

registering call

reactor.callLater(_interval, self.count, *args)

I have created Countdown class and it contains count function, I am calling it three time

reactor.callWhenRunning(Countdown().count, 1)
reactor.callWhenRunning(Countdown().count, 2)
reactor.callWhenRunning(Countdown().count, 3)

with different time interval, and I need to stop reactor when all call is finished. So is in twisted API have some method to know all call is completed.

My Code is

class Countdown(object):

    counter = 5

    def count(self, *args):
    _interval = args[0]
        name = args[1]
        if self.counter == 0 and name == "Third Call":
            reactor.stop()
        elif self.counter == 0:
        print name, " Finished..!"
        else:
            print self.counter, '...'
            self.counter -= 1
            reactor.callLater(_interval, self.count, *args)

from twisted.internet import reactor

reactor.callWhenRunning(Countdown().count, 1, "First Call")
reactor.callWhenRunning(Countdown().count, 2, "Second Call")
reactor.callWhenRunning(Countdown().count, 3, "Third Call")

print 'Start!'
reactor.run()
print 'Stop!'

Now I am using
if self.counter == 0 and name == “Third Call”:
to prevent my all counter process is finished. So now I need to know, is there in twisted have any built in method to know all call is finished or my all counter call is finished.

Answer 1

Twisted has an API for working with a list of events: DeferredList http://twistedmatrix.com/documents/current/core/howto/defer.html#auto8

Here is a small example how this might work:

from twisted.internet import defer 
from twisted.internet import reactor


def delayedFunction(dF):
    print('I was called')
    dF.success(True)

class Counter(object):
    def timeOffsetExecute(self,delay):
        dF = defer.Deferred()
        reactor.callLater(delay,delayedFunction,dF)
        return dF

def onAllResult(val):
    print 'All delayed functions called'
    reactor.stop()

cp = Counter()

dl = defer.DeferredList([cp.timeOffsetExecute(1), cp.timeOffsetExecute(3), cp.timeOffsetExecute(9)], consumeErrors=True)
dl.addCallback(onAllResult)

reactor.run()