multithreading - Leaky bucket in python -

hi trying develop leakybucket unlimited bucket capacity in python. want thread-safe , cpu efficient, minimum number of threads. works now. there tiny errors.

i throttle bandwidth 500 kbps. third line seems break this. also, can tell me if right way implement leakybucket? thanks.

rate: 500.00 rate: 500.00 rate: 550.00 rate: 500.00 rate: 500.00 rate: 500.00 rate: 500.00 rate: 500.00

code here:

from collections import deque import threading, time class leakybucket:     '''the leaky bucket throttling bit rate'''      def __init__(self, node, bitspersec, measintv, lbtype):         self.node = node         self.bitspersec = bitspersec  #the rate limit         self.measintv = measintv      #the measure interval, tokens become full @ beginning of each interval         self.lbtype = lbtype          #the type of bucket           self.lasttime = 0             #the start time of last measure interval         self.bitsdone = 0             #the bits have been transmitted         self.bdlock = threading.lock() #the lock bits sent         self.packdq = deque()          #the packet q          self.maxtoken = bitspersec*float(measintv)  #the max token (bits)         self.token = self.maxtoken      #the current token         self.condition = threading.condition()  #sync lock       def packin(self, msg):         '''insert packet'''         self.condition.acquire()         self.packdq.append(msg)         self.condition.notify()         self.condition.release()      def keeppoping(self):         '''keep poping new pack'''         self.lasttime = time.time()   #record start time         while true:             timenow = time.time()              if  timenow - self.lasttime > self.measintv:                      #new intv, need reset token                 self.token = self.maxtoken                 self.lasttime = timenow             self.condition.acquire()             if self.packdq: # queue not empty                 pack = list(self.packdq)[0]                 packlen = len(pack[2])*8                 if  packlen > self.token:   #no enough token?                     #self.packdq.popleft()                     self.condition.release()                     time.sleep(max(self.lasttime+self.measintv-time.time(),0)) #wait enough token                     else:              #enough token, can send out packet                     self.packdq.popleft()                     self.condition.release()                     self.changebitsdone(packlen)                     self.token = self.token - packlen #consume token             else:                 self.condition.wait()                 self.condition.release()      def begin(self):         '''begin leakybucket'''         athread = threading.thread(target = self.keeppoping, args = [])         athread.start()       def getbitsdone(self):         '''get , reset bitsdone, testing'''         self.bdlock.acquire()         rev = self.bitsdone         self.bitsdone = 0         self.bdlock.release()         return rev      def changebitsdone(self,length):         '''change bitsdone, testing'''         self.bdlock.acquire()         self.bitsdone += length         self.bdlock.release()      def measure(self, intv):         '''measure throughput of leaky bucket'''         while true:             bitsdone = self.getbitsdone()             rate = bitsdone / float(intv*1024)             print 'rate: %.2f' % rate             time.sleep(intv)      def startmeasure(self, intv):         '''start measure rate'''         #print 'here'         athread = threading.thread(target = self.measure, args = [intv])         athread.start()          #=============================== def main():     pack = 1000*'a'     msg = ('192.168.1.1', 16000, pack)     print 'here'     lb = leakybucket(none, 500*1024, 1, 'reg')     lb.begin()     lb.startmeasure(10)     nummsg = 0      while nummsg < 10000:         lb.packin(msg)         #print 'pack in'         nummsg += 1  if __name__ == '__main__':     main()