Mailman 3 October 2008 - Twisted

[Twisted-Python] callLater -- only when idle
by Peter Jacobi Oct. 30, 2008

Oct. 30, 2008

I'd like to schedule a delayed call for being done after n seconds of idling, i.e. n seconds after the last event was dispatched. I assume this can be done by resetting the delayed call from every event handler, but this seems to be a silly solution. Any suggestions for a better solution? Regards, Peter

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[Twisted-Python] txAMQP 0.2 released, now with Thrift superpowers
by Esteve Fernandez Oct. 29, 2008

Oct. 29, 2008

Hi all, I'm pleased to announce that Fluidinfo is releasing txAMQP 0.2, (codenamed "Peanut butter and chocolate") [1] which includes support for Thrift, and various minor fixes. What does this mean? Well, it makes easier to build a high performance [2] massively scalable [3] RPC [4] architecture in Python. We hope you'll enjoy it! PS: you'll need to apply the patch at [5] to Thrift to add support for Twisted 1 - txAMQP http://launchpad.net/txamqp 2 - thanks to Twisted http://www.twistedmatrix.com 3 - thanks to AMQP http://www.amqp.org 4 - thanks to Thrift http://incubator.apache.org/thrift 5 - https://issues.apache.org/jira/browse/THRIFT-148

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[Twisted-Python] irc server run by twisted and (probably) django
by Manuel Meyer Oct. 29, 2008

Oct. 29, 2008

Hi, I am new to twisted - so I am not very into it yet. I want to create a IRC Server that reacts a little bit different compared to others: * only registered users will be able to /list channels and /join them. * /list only returns channels the user registered * /join is only apply-able on those channels, too * /join new-channel won't work * Registering and channel-creation is done not in IRC but in a website, probably driven by django. Any comment on this is welcomed * where should I start? * readings? * examples? * existing similar projects? Thanks, Manuel

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[Twisted-Python] Shared memory for multiple twisted servers
by Alec Matusis Oct. 29, 2008

Oct. 29, 2008

I am thinking of writing 8 identical twisted servers that would run on an 8 core machine and would have shared memory objects (lists or maybe dictionaries), that they can all access and modify. Perhaps somewhat similar to multiprocessing module in python 2.6. What is the best way of doing this?

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[Twisted-Python] Passing revieved rata and erroring out bad passowrds
by Brian Levin Oct. 28, 2008

Oct. 28, 2008

I apologizes if these are simple questions. I am a complete newb when it comes to python and twisted. I am trying to pass a command via ssh to a server. I am having 2 problems. I am hoping that someone can help me. I have been unable to find answers in "the google". Problem 1: I am unable to pass the received data to a variable without creating a global. As a general rule it is my understanding that the use of globals in python should be avoided. If there is a better method for passing the data variable out of the dataReceived method I would prefer to use it. Problem 2: A bad password or username causes and infinite loop. I need to find a way to cause an error or return a false value when the password or username is bad. I have included my code below. Any help would be most appreciated. Thank you in advance --Brian Levin <code> from twisted.conch.ssh import transport, userauth, connection, channel from twisted.conch.ssh.common import NS from twisted.internet import defer, protocol, reactor from twisted.python import log from getpass import getpass class Transport(transport.SSHClientTransport): def verifyHostKey(self, hostKey, fingerprint): print 'host key fingerprint: %s' % fingerprint return defer.succeed(1) def connectionSecure(self): self.requestService(UserAuth(USER, Connection())) class UserAuth(userauth.SSHUserAuthClient): def getPassword(self): return defer.succeed(getpass("password: ")) def getPublicKey(self): return # Empty implementation: always use password auth class Connection(connection.SSHConnection): def serviceStarted(self): self.openChannel(Channel(2**16, 2**15, self)) class Channel(channel.SSHChannel): name = 'session' # must use this exact string def openFailed(self, reason): print '"%s" failed: %s' % (CMD,reason) def channelOpen(self, data): self.welcome = data # Might display/process welcome screen d = self.conn.sendRequest(self,'exec',NS(CMD),wantReply=1) def dataReceived(self, data): global test test = data def closed(self): self.loseConnection() reactor.stop() USER = raw_input('User: ') HOST = raw_input('Host: ') CMD = raw_input('CMD: ') protocol.ClientCreator(reactor, Transport).connectTCP(HOST, 22) reactor.run() print test </code>

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[Twisted-Python] Re: Consensus on speed of deferred call/errback-style execution?
by Andrew Francis Oct. 26, 2008

Oct. 26, 2008

Hi Glyph: > I think inlineCallbacks is neat, InlineCallbacks are neat! InlineCallbacks perform much of what I do with Stackless Python and Twisted. One of these days, I would like to run tests to compare the two. I suspect there is additional overhead (from what I recall, I see stuff in the code like unwinding stacks/checks for infinite recursion) >but its strength is really operations that are truly conversational; >where the calling end of the conversation actually does need to wait for >each step of an asynchronous conversation to complete before moving on to >the next one. And a lot of the new Web APIs are conversational in nature! I think inlineCallbacks will grow in importance as web programmes move from mashups to orchestrations/choreographies. Cheers, Andrew

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com Oct. 25, 2008

Oct. 25, 2008

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[Twisted-Python] RAW Sockets, IP in UDP
by Lars Reimann Oct. 25, 2008

Oct. 25, 2008

Hi all, I am new to this list, but I have some hopefully simple questions for you. I need to implement a listening RAW sockets which gives me all packets at that particular interface. Next, I need to put this data into a normal UDP container to send it to another host, where it is unpacked again. I am studying all the docs now, but any hints would be greatly appreciated! Thx in advance.

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Re: [Twisted-Python] Consensus on speed of deferred call/errback-style execution?
by Terry Jones Oct. 24, 2008

Oct. 24, 2008

Hi JP >>>>> "JP" == Jean-Paul Calderone <exarkun(a)divmod.com> writes: JP> Possibly, but maybe trickier than you hope. This is basically what is JP> called the "stackless transform" in PyPy. It's about a thousand lines JP> for them to implement, and it only works on RPython, not Python. Unfortunately, everything is trickier than I hope :-) Thanks - I keep meaning to play with PyPy, but I never have. One day... T

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Re: [Twisted-Python] Consensus on speed of deferred call/errback-style execution?
by Terry Jones Oct. 24, 2008

Oct. 24, 2008

>>>>> "glyph" == glyph <glyph(a)divmod.com> writes: glyph> I don't believe there's been any extensive profiling of glyph> inlineCallbacks. At least, none that I'm aware of. I think what glyph> you are remembering is that inlineCallbacks generally results in an glyph> (often implicit, sometimes unintentional) loss of parallelism. Yes, it's possible that the person I heard from informally was thinking of this of had heard something along these lines, etc. It's funny, Esteve and I were talking about code like your example just a few days ago. You have to know what you're doing. I agree the best/simplest example is where you have some form of loop and you should use a DeferredList, else you're implicitly serializing things that could be launched virtually all at once and finishing in any order at all. I'm interested not in those cases though, but in whether there's some mechanical (due to Python) advantage to one style of coding versus another. I might play a little more. I was going to write some code to generate different varieties of behaviorally-equivalent but differently structured code. In fact I think it wouldn't be hard to write something that could write your code for you in a variety of ways. E.g., you could write pseudo-code like a = A() if a < 45: b = B() c = a + b.hey() - C() if c: return D(12, c) else: return E() return F(a) and something digs through this code, figures out (maybe via a decorator used on functions returning a deferred - ugh, but it's just one suggestion) which of A, B, C, D and E return deferreds and spits out code to handle things for you. I could say more, but I'm sure no-one would reply :-) Thanks! Terry

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