[Zope-dev] thread restrictions?

[Robin Becker]

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