[Twisted-Python] locking threads when deferToThread is used

[Ladislav Andel]

Thank you for your help.
Well, I'm trying to get into the problem step by step so please receive 
my apologies about not so professional approach
to the problem.

I have following code below with a few problems.

1) I need to call getServerResponse of SIP servers for given list 
domains periodically.
    I have tried to use callLater method but probably at wrong places.
This way it runs only once. In the future it should be at least every 5 
minutes.

2)
In my code is something wrong.
I get the Server response but also following error.

Traceback (most recent call last):
 File 
"/home/data/iptel_summer_2007/sipcraft1/src/sipcraft/multideferred.py", 
line 46, in ?
   reactor.run()
 File "/usr/lib/python2.4/site-packages/twisted/internet/posixbase.py", 
line 220, in run
   self.mainLoop()
 File "/usr/lib/python2.4/site-packages/twisted/internet/posixbase.py", 
line 228, in mainLoop
   self.runUntilCurrent()
--- <exception caught here> ---
 File "/usr/lib/python2.4/site-packages/twisted/internet/base.py", line 
533, in runUntilCurrent
   f(*a, **kw)
 File "/usr/lib/python2.4/site-packages/twisted/internet/defer.py", line 
239, in callback
   self._startRunCallbacks(result)
 File "/usr/lib/python2.4/site-packages/twisted/internet/defer.py", line 
290, in _startRunCallbacks
   raise AlreadyCalledError
twisted.internet.defer.AlreadyCalledError:




----------------------------- code ---------------------------------


from twisted.internet import reactor, defer, threads

from siptest import siptest_f
from twisted.internet.threads import deferToThread


test_opts = 
{'username':'test','transport':'udp','localport':'5085','password':'test'}
domain = ['sip.1und1.de', 'sip.babble.net']

class Getter:
     def gotResults(self, domain, test_opts):
             if len(domain) != 0:
           self.d.callback(siptest_f(domain, test_opts))
       else:
           self.d.errback(ValueError("You used an odd number!"))

   def _print(self, r, domain):
             return domain, r
       def getServerResponse(self, domain, test_opts):
                     self.d = threads.deferToThread(self.gotResults, 
domain, test_opts)
       self.d.addCallback(self._print, domain)
       return self.d

def printData(d):
   print d

def printError(failure):
   import sys
   sys.stderr.write(str(failure))

def test():
   for dom in domain:
       g = Getter()
       d = g.getServerResponse(dom, test_opts)
       d.addCallback(printData)
       d.addErrback(printError)

if __name__ == '__main__':
   test()
   reactor.run()