Re: [Zope-dev] thread restrictions?

23 Jul 1999


      In article <dB5WjDAvs8l3EwOl@jessikat.demon.co.uk>, Robin Becker
<robin@jessikat.demon.co.uk> writes
I am a moron this orderedjobs thing is using a polling loop
...
Are there any restrictions on using threads in ExternalMethods I am trying to 
figure
out why my cpu usage goes to 100% after calling the function TGA_CALC below as 
an
ExternalMethod. The OrderedJobs thingy is intended to arbitrate a first come 
first
served policy for my cpu hog calculations which being memory intensive as well I 
want
only one job ever to be initialised and running.
#TZGA.py proxy for the real calculation
from DateTime import DateTime
from OrderedJobs import OrderedJobs
from Queue import Full
_Jobs=OrderedJobs()
def     _TGA_RUN():
       for i in xrange(1000):
               t=DateTime('GMT').rfc822()
       return t
def TGA_CALC():
       global _Jobs
       try:
               return _Jobs.add(_TGA_RUN,args=(),kwargs={})
       except Full:
               raise "couldn't add job "
##########################################
##### the OrderedJobs module
'''
Module to implement ordered locking
'''
from thread import *
from Queue import Queue, Full
class _Item:
       def __init__(self,func=None,args=(),kwargs={}):
               self.args=args
               self.kwargs=kwargs
               self.func=func
               self.lock=allocate_lock()
class OrderedJobs:
       def __init__(self,maxsize=5):
               self.Q=Queue(maxsize)
               self.serve=1
               self.T=start_new_thread(self.run,())
def run(self):
               while self.serve:
                       if not self.Q.empty():
                               item=self.Q.get(0)
                               if item.func:
                                       item.result=apply(item.func,
                                                   item.args,item.kwargs)
                               else:
                                       item.result=None
                               item.lock.release()
def add(self,func,args=(),kwargs={}):
               if self.Q.full(): raise Full
               item=_Item(func,args,kwargs)
               item.lock.acquire()
               self.Q.put(item)
               item.lock.acquire()
               item.lock.release()
               return item.result
if __name__=='__main__':
       import time
       def testJob(n,delay):
               print 'starting testJob ',n, delay
               time.sleep(delay)
               print 'finished testJob ',n
               return None
       def addJob(i,delay):
               print 'adding job',i
               try:
                       Q.add(testJob,(i,3.7))
               except Full:
                       print "couldn't add job ",i
Q=OrderedJobs()
       for i in range(1,18):
               start_new_thread(addJob,(i,3.7))
               time.sleep(0.7)
###############################
-- 
Robin Becker