Mailman 3 April 2009 - Twisted

[Twisted-Python] cx_Oracle, Twisted - rollback failed
by Steve Lewis 30 Apr '09

30 Apr '09

(If anyone gets this twice, apology in advance. I think I jumped the gun in sending the email before I got my acknowledge welcome email for the list.) It looks like the latest version 8.2 tries to rollback without seeing if the connection is even open or not: def rollback(self): if not self._pool.reconnect: self._connection.rollback() return try: self._connection.rollback() curs = self._connection.cursor() curs.execute(self._pool.good_sql) curs.close() self._connection.commit() return except: log.err(None, "Rollback failed") self._pool.disconnect(self._connection) if self._pool.noisy: log.msg("Connection lost.") raise ConnectionLost() I'm seeing the "Rollback failed" log message and then the ConnectionLost exception being thrown. I have cp_reconnect set to True, so it's skipping down to the try/except and failing on rollback. Should the code try to rollback if the connection is lost? Thanks in advance, Steve

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[Twisted-Python] handling CTRL-C
by Fabrizio Mancini 30 Apr '09

30 Apr '09

Hi, i know twisted already manage CTRL-C keystroke, but i'd like to add some other action when CTRL-C is pressed. I've implemented a perspective broker server, which have a DeferredQueue and a lot of elements in it. I'd like to write to a file all those elements before the program shuts down. Is there a way to handle this kind of situation? Thanks in advance Fabrizio

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[Twisted-Python] Catching exception on a Serial Connection
by Nestor A. Diaz 30 Apr '09

30 Apr '09

Hello, i am newbie to twisted, i am trying to find a way to catch exceptions raised from a protocol over a serial line, like the twisted.protocol.gps.zodiac, i see the demo script, on the twisted website: http://twistedmatrix.com/projects/core/documentation/examples/gpsfix.py but i don't figure yet how to handle exceptions coming from the protocol since i didn't figure how to register a callback for an error, cause i haven't found a way to create a deferred object for a serial connection. for example, the gpsfix.py main portion is as simple as this: s = SerialPort(GPSTest(), o.opts['port'], reactor, baudrate=baudrate) reactor.run() whereas GPSTest() is a class that inherits from protocol.Protocol, source code on: http://twistedmatrix.com/trac/browser/tags/releases/twisted-8.2.0/twisted/p… Any help would be appreciated. thanks. -- Nestor A. Diaz Ingeniero de Sistemas Tel. +57 1-600-5490 x 211 Cel. +57 316-227-3593 Tel. SIP: sip:211@tiendalinux.com Email/MSN: nestor(a)tiendalinux.com http://www.tiendalinux.com/ Bogota, Colombia

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[Twisted-Python] deferToThread help
by Minesh Patel 29 Apr '09

29 Apr '09

Sorry if this is a newbie question. I have a blocking function that I defer to thread, let's say 'foo' and I would like to add a callback that gets called after say 10 minues after Thread finishes def foo(): # Blocks for a while def bar(): # Do some stuff d = threads.deferToThread(foo) d.addCallback(bar) # How can I add timing to the callback??? Currently I have the following code which works but doesn't account for the threads execution time: reactor.callInThread(self.bootIso, self.iloIp, pathToIsoRename) # 10 minutes sleep d = task.deferLater(reactor, 600, bar) -- Thanks, ./Minesh

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Re: [Twisted-Python] cx_Oracle, Twisted - rollback failed
by Jean-Paul Calderone 29 Apr '09

29 Apr '09

On Wed, 29 Apr 2009 10:39:30 -0700 (PDT), Steve Lewis <spiritualmechanic(a)yahoo.com> wrote: >It looks like the latest version 8.2 tries to rollback without seeing if the connection is even open or not: > > def rollback(self): > if not self._pool.reconnect: > self._connection.rollback() > return > > try: > self._connection.rollback() > curs = self._connection.cursor() > curs.execute(self._pool.good_sql) > curs.close() > self._connection.commit() > return > except: > log.err(None, "Rollback failed") > > self._pool.disconnect(self._connection) > > if self._pool.noisy: > log.msg("Connection lost.") > > raise ConnectionLost() > >I'm seeing the "Rollback failed" log message and then the ConnectionLost exception being thrown. I have cp_reconnect set to True, so it's skipping down to the try/except and failing on rollback. Should the code try to rollback if the connection is lost? Is there some way it can determine that the connection has been lost aside from trying the rollback (and is compatible with other DB-API 2.0 modules)? Jean-Paul

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[Twisted-Python] cx_Oracle, Twisted - rollback failed
by Steve Lewis 29 Apr '09

29 Apr '09

It looks like the latest version 8.2 tries to rollback without seeing if the connection is even open or not: def rollback(self): if not self._pool.reconnect: self._connection.rollback() return try: self._connection.rollback() curs = self._connection.cursor() curs.execute(self._pool.good_sql) curs.close() self._connection.commit() return except: log.err(None, "Rollback failed") self._pool.disconnect(self._connection) if self._pool.noisy: log.msg("Connection lost.") raise ConnectionLost() I'm seeing the "Rollback failed" log message and then the ConnectionLost exception being thrown. I have cp_reconnect set to True, so it's skipping down to the try/except and failing on rollback. Should the code try to rollback if the connection is lost? Thanks in advance, Steve

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[Twisted-Python] Polling from Twisted
by Juanjo Conti 28 Apr '09

28 Apr '09

Hi, this is my first mail to the list. I am writing a server using Twisted, extending LineOnlyReceiver. In it I maintain a list of clients connected. I'd like to poll every client for certain status information every 30 seconds. Which is the correct approach to implement this? Thanks in advance, -- Juanjo Conti

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[Twisted-Python] Upcoming Twisted Sprint in Cambridge, MA
by Jean-Paul Calderone 27 Apr '09

27 Apr '09

Hello All, I'd like to organize another Twisted sprint in Cambridge, MA in May. As with previous sprints, this is an all day event, most likely hosted at the Divmod office in Porter Square, for Twisted hacking. Chris Armstrong has raised plugin system improvements as a possible topic. Other topics are welcome as well, of course. It's been a couple months since our last sprint. I think it would be nice to have a sprint early in May and another one late in May. How do people feel about May 2nd or 3rd for the first sprint? Jean-Paul

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[Twisted-Python] xmlrpc - Possable failure to understand async concept
by Tim Hughes 26 Apr '09

26 Apr '09

I am trying to understand this concept of async methods and i thought I had it cracked with the code below but it doesn't seem to work as all the calls to the xmlrpc server return one after the other like this: Success:I started at Fri Apr 24 01:12:23 2009 and i slept 5 seconds then woke at Fri Apr 24 01:12:28 2009 Success:I started at Fri Apr 24 01:12:28 2009 and i slept 5 seconds then woke at Fri Apr 24 01:12:33 2009 Success:I started at Fri Apr 24 01:12:33 2009 and i slept 5 seconds then woke at Fri Apr 24 01:12:38 2009 Success:I started at Fri Apr 24 01:12:38 2009 and i slept 5 seconds then woke at Fri Apr 24 01:12:43 2009 Success:I started at Fri Apr 24 01:12:43 2009 and i slept 5 seconds then woke at Fri Apr 24 01:12:48 2009 Success:I started at Fri Apr 24 01:12:48 2009 and i slept 5 seconds then woke at Fri Apr 24 01:12:53 2009 Am I completly missing the point here or is there something incorrect with my code. AT first I thought it was because the sleep was shutting the whole thing down (probably is) so I have also tried it with a long running network call instead of the time.sleep() and have the same issue. Can someone please point me in the right direction or give a bit of criticism of the code concepts/thought processes =========== Server ======================== #!/usr/bin/env python from twisted.web import xmlrpc, server from twisted.internet.defer import Deferred from twisted.internet import reactor, threads import time class MyServer(xmlrpc.XMLRPC): def blocking_method(self, duration=5): """block the instance for a specified duration""" started = time.asctime() time.sleep(duration) data = "I started at %s and i slept %d seconds then woke at %s" % (started, duration, time.asctime()) return data # def xmlrpc_block_thread(self, duration=10): # """ pass to blocking method using thread """ # return threads.deferToThread(self.blocking_method, duration) # # def xmlrpc_block(self, duration=10): # """ pass to blocking method using defered """ # d = Deferred() # d.callback(self.blocking_method(duration)) # return d def xmlrpc_block_fixed(self, duration=5): """ pass to blocking method using defered """ d = self.blocking_method_fixed(duration) # return a defered d.addCallback(self.printdata) d.addErrback(self.printerror) return d def blocking_method_fixed(self, duration=5): d = Deferred() d.callback(self.blocking_method(duration)) return d def printdata(self, val): return 'Success:'+val def printerror(self, val): return 'Error:'+val if __name__ == '__main__': r = MyServer() reactor.listenTCP(8080, server.Site(r)) reactor.run() =============================================== ========== Client ================================ #!/usr/bin/env python import xmlrpclib import datetime import sys proxy = xmlrpclib.ServerProxy("http://localhost:8080/", allow_none=True) print "%s" % str(proxy.block_fixed(5)) =============================================== Tim Hughes mailto:thughes@thegoldfish.org

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com 26 Apr '09

26 Apr '09

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