Twisted Countdown Etude 1

# A solution to exercise 1 of the Twisted tutorial at http://krondo.com/?p=1333

import time

class Countdown(object):

    def __init__(self, name, ticks, rate):
        self.name, self.counter, self.rate = (name, ticks, rate)

    def count(self):
            print '{}: {:>2} ticks left at {} sec/tick ...'.format(self.name, self.counter, self.rate)
            self.counter -= 1

class CountdownPool(object):

    def __init__(self, *args):
        self.pool = [Countdown(name, ticks, rate) for name, ticks, rate in args]
        self.pending = len(self.pool)

    def start(self):
        self.startTime = time.time()
        for ctdn in self.pool:
            self.count(ctdn)

    def count(self, ctdn):
        if ctdn.counter > 0:
            ctdn.count()
            reactor.callLater(ctdn.rate, self.count, ctdn)
        else:
            print 'Counter {} complete! ({:.3f} sec)'.format(ctdn.name, time.time()-self.startTime)
            self.pending -= 1
            if not self.pending: reactor.stop()



from twisted.internet import reactor

pool = CountdownPool(['one', 5, 1.0], ['two', 13, .3], ['tri', 8, .8])
reactor.callWhenRunning(pool.start)

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


#### Output ####

Start!
one:  5 ticks left at 1.0 sec/tick ...
two: 13 ticks left at 0.3 sec/tick ...
tri:  8 ticks left at 0.8 sec/tick ...
two: 12 ticks left at 0.3 sec/tick ...
two: 11 ticks left at 0.3 sec/tick ...
tri:  7 ticks left at 0.8 sec/tick ...
two: 10 ticks left at 0.3 sec/tick ...
one:  4 ticks left at 1.0 sec/tick ...
two:  9 ticks left at 0.3 sec/tick ...
two:  8 ticks left at 0.3 sec/tick ...
tri:  6 ticks left at 0.8 sec/tick ...
two:  7 ticks left at 0.3 sec/tick ...
one:  3 ticks left at 1.0 sec/tick ...
two:  6 ticks left at 0.3 sec/tick ...
tri:  5 ticks left at 0.8 sec/tick ...
two:  5 ticks left at 0.3 sec/tick ...
two:  4 ticks left at 0.3 sec/tick ...
one:  2 ticks left at 1.0 sec/tick ...
two:  3 ticks left at 0.3 sec/tick ...
tri:  4 ticks left at 0.8 sec/tick ...
two:  2 ticks left at 0.3 sec/tick ...
two:  1 ticks left at 0.3 sec/tick ...
Counter two complete! (3.901 sec)
tri:  3 ticks left at 0.8 sec/tick ...
one:  1 ticks left at 1.0 sec/tick ...
tri:  2 ticks left at 0.8 sec/tick ...
Counter one complete! (5.001 sec)
tri:  1 ticks left at 0.8 sec/tick ...
Counter tri complete! (6.402 sec)
Stop!