Hi,
Probably not the best group to post my question but I'm sure there is
some people here that use Twisted.
First here is the beginning of my source code:
from twisted.internet import reactor, defer, threads
import time
class CompilerThread(object):
def __init__(self, task, delay):
self.task = task
self.delay = delay
def _processing(self, delay):
print 'Start :', self.task
# Simulate delayed result, to fire immediately use
self.d.callback(self.task)
time.sleep(delay)
return self.task
def compile(self):
print 'Compile :', self.task
print self
# Create Deferred in another thread and add callback
self.d = threads.deferToThread(self._processing,
self.delay).addCallback(self.print_result)
# Return the deferred, this way you could add callback later
return self.d
def print_result(self, result):
# Print result
print 'Compiler result :', result, self.task
# MUST return result otherwise next callback receive None
return result
# Create Compiler objects
ct1 = CompilerThread('*OBJECT 1*', 2)
ct2 = CompilerThread('*OBJECT 2*', 3)
ct3 = CompilerThread('*OBJECT 3*', 5)
# Use succeed to create a deferred already fired
d = defer.succeed(None)
Now my problem:
With this code everything work fine:
d.addCallback(lambda result: ct1.compile())
d.addCallback(lambda result: ct2.compile())
d.addCallback(lambda result: ct3.compile())
reactor.callLater(20, reactor.stop)
reactor.run()
Output:
Compile : *OBJECT 1*
<__main__.CompilerThread object at 0x00BAD070>
Start : *OBJECT 1*
Compiler result : *OBJECT 1* *OBJECT 1*
Compile : *OBJECT 2*
<__main__.CompilerThread object at 0x00BAD050>
Start : *OBJECT 2*
Compiler result : *OBJECT 2* *OBJECT 2*
Compile : *OBJECT 3*
<__main__.CompilerThread object at 0x00CDA4B0>
Start : *OBJECT 3*
Compiler result : *OBJECT 3* *OBJECT 3*
But when I try to replace this code with a for loops, something goes
wrong:
l = [ct1, ct2, ct3]
for c in l:
d.addCallback(lambda result: c.compile())
reactor.callLater(20, reactor.stop)
reactor.run()
Output:
Compile : *OBJECT 1*
<__main__.CompilerThread object at 0x00BAD030>
Start : *OBJECT 1*
Compiler result : *OBJECT 1* *OBJECT 1*
Compile : *OBJECT 3*
<__main__.CompilerThread object at 0x00CD9470>
Start : *OBJECT 3*
Compiler result : *OBJECT 3* *OBJECT 3*
Compile : *OBJECT 3*
<__main__.CompilerThread object at 0x00CD9470>
Start : *OBJECT 3*
Compiler result : *OBJECT 3* *OBJECT 3*
OBJECT 3 run 2 times and OBJECT 2 never ?!?
Any idea ? Maybe something related to Threads ?
Thanks for your help.
--
http://mail.python.org/mailman/listinfo/python-list
