Mailman 3 July 2008 - Twisted

[Twisted-Python] Async file access
by Vasil Vangelovski July 18, 2008

July 18, 2008

Which is the best practice to read a file asyncrouniously? Should I just read it with open and return the result in a callback or is there a lower level API that's more appropriate?

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[Twisted-Python] Deferred.setTimeout is deprecated, replacement ideas?
by Gabriel Rossetti July 17, 2008

July 17, 2008

Hello everyone, I was going to use Deferred.setTimeout until I saw that it was deprecated. Does anyone know why? I found it handy and I find that case-per-case replacements tend to be complicated. Does anyone have any ideas on how to replace it? I have a queue containing read results from I/O, the get() method returns a deferred fired when the data arrives (sort of like defer.DeferredQueue). Since I need to be able to set a read timeout, i.e. if the data doesn't arrive after a certain … [View More]

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[Twisted-Python] cross service events and why on earth ?
by skoegl＠online.de July 16, 2008

July 16, 2008

hi, I have to deal with flash players (I'm deeply ashamed for what I'm doing ;-), and their somewhat cumberstone constraints. The main part of the communication is handled via an tcp socket using the amf protocol. But I have to handle "file uploads" via http POST multipart from client to server and sending it back to the flash player since flash only allows domain specific content - no content from the users' file system. So my first attempt to … [View More]

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[Twisted-Python] twisted adbapi question
by Vasil Vangelovski July 15, 2008

July 15, 2008

does anyone know why is twisted.enterprise.adbapi.safe deprecated? What should I use instead?

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[Twisted-Python] Twisted Hosting and Twisted in the Cloud
by Duncan McGreggor July 14, 2008

July 14, 2008

Hey everyone, Divmod's been talking to various hosting companies about potential Twisted deals (and maybe even support). I wanted to get a gauge of people's level of interest in the services we've been discussing. We're currently looking at the following options: * Dedicated hosts, with Twisted libs pre-installed on them * Virtual hosts/"slices" with Twisted libs pre-installed on them * Clouds that support uploading and running Twisted apps * Potential support contracts where Divmod … [View More]

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[Twisted-Python] trial & ThreadedResolver._cleanup
by Justin Mazzola Paluska July 14, 2008

July 14, 2008

Hi, I’m writing a bunch of unit tests using Twisted’s Trial. I’ve been trying to chase down some issues with my code leaving the reactor unclean. I think I’ve gotten most of them out of the way, except for one: /usr/lib/python2.4/site-packages/twisted/trial/reporter.py:142: twisted.trial.reporter.BrokenTestCaseWarning: REACTOR UNCLEAN! traceback(s) follow: File "/usr/lib/python2.4/site-packages/twisted/trial/util.py", line 72, in _dispatch getattr(self, "do_%s" % attr)() File "/usr/… [View More]

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[Twisted-Python] stdio.StandardIO and control keys
by mayamatakeshi July 14, 2008

July 14, 2008

Hello, I've just started learning twisted. I'm trying to build an utility to connect to a tcp port (telnet-like) and exchange messages with an application. I'm using twisted.internet.stdio.StandardIO passing a Protocol to its constructor (I'm tinkering with the dataforward.py example from the twisted book). I'm adding preprocessing to this utility so that I can check what the user has input before sending it to the peer. So far it is working fine, as I just have to override the method Protocol.… [View More]

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[Twisted-Python] trial and python 2.5.2?
by Mikhail Terekhov July 14, 2008

July 14, 2008

Hi, I'm trying to run trial from twisted-8.1.0 on SuSE-11.0 with python 2.5.2 and get the following error (with super and old style classes IMHO). What would be the fix or workaround for this? BTW on SuSE-10.3 with python 2.5.1 everything is OK. Thank you Mike mike@linux-lp:~/python/twisted> tar jxf Twisted-8.1.0.tar.bz2 mike@linux-lp:~/python/twisted> cd Twisted-8.1.0 mike@linux-lp:~/python/twisted/Twisted-8.1.0> ./bin/trial twisted /home/mike/python/twisted/Twisted-8.1.0/… [View More]twisted/python/reflect.py:377: DeprecationWarning: twisted.flow is unmaintained. return __import__(importName) /home/mike/python/twisted/Twisted-8.1.0/twisted/scripts/test/test_mktap.py:16: DeprecationWarning: mktap and related support modules are deprecated as of Twisted 8.0. Use Twisted Application Plugins with the 'twistd' command directly, as described in 'Writing a Twisted Application Plugin for twistd' chapter of the Developer Guide. from twisted.scripts.mktap import run, getid /home/mike/python/twisted/Twisted-8.1.0/twisted/enterprise/util.py:19: DeprecationWarning: twisted.enterprise.util is deprecated since Twisted 8.0.0. category=DeprecationWarning) /home/mike/python/twisted/Twisted-8.1.0/twisted/test/test_persisted.py:161: DeprecationWarning: twisted.persisted.marmalade is deprecated from twisted.persisted import marmalade /home/mike/python/twisted/Twisted-8.1.0/twisted/words/im/__init__.py:8: UserWarning: twisted.im will be undergoing a rewrite at some point in the future. warnings.warn("twisted.im will be undergoing a rewrite at some point in the future.") Traceback (most recent call last): File "./bin/trial", line 24, in <module> run() File "/home/mike/python/twisted/Twisted-8.1.0/twisted/scripts/trial.py", line 361, in run test_result = trialRunner.run(suite) File "/home/mike/python/twisted/Twisted-8.1.0/twisted/trial/runner.py", line 780, in run suite = TrialSuite([test]) File "/home/mike/python/twisted/Twisted-8.1.0/twisted/trial/runner.py", line 263, in __init__ super(TrialSuite, self).__init__([suite]) TypeError: super() argument 1 must be type, not classobj Exception exceptions.TypeError: TypeError("'NoneType' object is not callable",) in <bound method Popen3.__del__ of <popen2.Popen3 instance at 0x933a78c>> ignored mike@linux-lp:~/python/twisted/Twisted-8.1.0> mike@linux-lp:~/python/twisted/Twisted-8.1.0> python --version Python 2.5.2 mike@linux-lp:~/python/twisted/Twisted-8.1.0> [View Less]

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com July 13, 2008

July 13, 2008

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[Twisted-Python] domish.Element comparison not working
by Gabriel Rossetti July 11, 2008

July 11, 2008

Hello everyone, I need to compare two domish.Element objects in a unit test using trial. I can't compare the string xml (using .toXml()) because sometimes the attributes are not in the same order, and since it's a string it uses normal string comparison and you see the problem, but I can't use direct comparison either, so what should I use? If you look at the example below you will see what I mean : >>> from twisted.words.xish import domish >>> root = domish.Element(('… [View More]

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[Twisted-Python] twisted and functional programming idioms
by Rodney D Price July 10, 2008

July 10, 2008

I'm just getting started with Twisted, and trying to find my way around. I've done quite a bit of functional programming (Haskell), where recursion is a very common idiom. I keep finding myself heading in that direction as I try to understand how to use Twisted. For example, if I wanted to write a loop in Haskell that woke up once a second and did something, I might write main = heartbeat heartbeat = do sleep 1000 doSomething heartbeat This code first sleeps for one second, then does … [View More]

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[Twisted-Python] AMP compliance tests
by Jonathan Lange July 10, 2008

July 10, 2008

Hello all, Where can I find a set of automated tests that check that a particular AMP implementation is complete? I seem to recall someone on #twisted mentioning that they were working on such a suite. thanks, jml

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[Twisted-Python] OSX Leopard version still at 8.0.1?
by Rodney D Price July 10, 2008

July 10, 2008

Is there a problem with 8.1.0 on Leopard (OSX 10.5)? I ran trial twisted on 8.1.0 and got some errors, but being new at Twisted, I'm not sure whether the errors were real or I just did something wrong. I'm primarily interested in twisted.word XMPP support. -Rod

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[Twisted-Python] Bloody Twisted VFS
by Andy Gayton July 10, 2008

July 10, 2008

Hey guys, I'm really keen to get twisted.vfs to a stable point that is acceptably releasable. There's 6 tickets to knock off to get it to this state: This ticket will give an easily runnable vfs server, which'll be useful for experimenting with vfs as it is worked on: * http://twistedmatrix.com/trac/ticket/2821 This ticket ports the backend vfs interface to be firstly async, and also, not quite so lame: * http://twistedmatrix.com/trac/ticket/2815 Then we can port the 3 currently … [View More]

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[Twisted-Python] deferToThread in unittest (trial)?
by Gabriel Rossetti July 9, 2008

July 9, 2008

Hello, I have a quick question, are there any known side-effects/problems/limitations with using deferToThread in unit-tests (trial)? I'm actually testing a class that uses a class that has a call to deferToThread, the problem is that the callbacks are never called, even if the function passed to deferToThread does nothing (so it should return). Thanks, Gabriel

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[Twisted-Python] synchronous problem
by Wu Zhe July 9, 2008

July 9, 2008

Hi I have a series of files to transfer, each followed by a line sent to specify the file size and crc number. As we can see here I need synchronous behavior, only after the previous file transfer complete, can the for loop step into the next iteration to send the next file via sender.beginFileTransfer. How can i achieve this? Here is the problematic code: def import_query(self, path_list): number_of_files = len(path_list) line = '3#%s' % number_of_files self.… [View More]

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[Twisted-Python] Re: [Twisted-bugs] pydoctor should put the module name at the beginning of the document title
by Stephen Waterbury July 9, 2008

July 9, 2008

trac(a)twistedmatrix.com wrote: > New submission from TimAllen <tim(a)commsecure.com.au>: > [description] pydoctor is not part of twisted -- it's a separate project, with its own bug tracker. See: http://codespeak.net/~mwh/pydoctor/ Steve

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[Twisted-Python] Gc of deferreds
by Rutt, Benjamin July 8, 2008

July 8, 2008

In the following program, what prevents the deferred "d" from being gc'd? (nothing saves the return of foo() in any variable). Do I need to keep a reference to it around to ensure the callbacks will run? #!/usr/bin/env python from twisted.internet import defer,reactor,utils def foo(): d = utils.getProcessOutput('sleep', args=['2']) def cb(data): print "cb fired" return data d.addCallback(cb) return d foo() reactor.callLater(5, reactor.stop) reactor.run() … [View More]

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[Twisted-Python] uninstall Twisted-8.1.0
by raja pavankumar July 8, 2008

July 8, 2008

hello, I need to uninstall Twisted-8.1.0 and use Twisted-2.2.0. Can some one help me as to how to uninstall Twisted-8.1.0. Thanks in advance rajainnov

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[Twisted-Python] cred realm with __init__ methods under twistd
by Ross Vandegrift July 8, 2008

July 8, 2008

Hello everyone, I'm working on a twisted application that uses cred and pb. I'm having a bit of trouble getting my realm working as I want. In my .tac file, I have this: p = portal.Portal(CNDRealm()) c = checkers.InMemoryUsernamePasswordDatabaseDontUse(user="passwd") p.registerChecker(c) application = service.Application("receiver") service = service.IServiceCollection(application) factory = pb.PBServerFactory(p) internet.TCPServer(8800, factory).setServiceParent(service) My realm, … [View More]

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[Twisted-Python] [SIP]
by Rémi BUISSON July 7, 2008

July 7, 2008

Hi everyone, I didn't succeed in using twisted.protocols.sip ? Do you have a simple example for me ? It will be very nice ... Thanks in advance !

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[Twisted-Python] Confusion on Twisted versions
by happybrowndog July 6, 2008

July 6, 2008

I'm finding the Twisted version numbers confusing. I have it installed on Debian, where aptitude is telling me that 2.4.4 is installed (with python 2.4). However, the TwistedMatrix site states that there is an 8.1 version. Googling shows that people talk of 2.4x and 8.x in an intermingled fashion. Can someone please clarify?

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[Twisted-Python] The right way to change a global variable in a Twisted server?
by happybrowndog July 6, 2008

July 6, 2008

Is there a right way to change a global variable in a Twisted server (this one is using PerspectiveBroker)? What I am trying to do is allow perspectivebroker clients to update a global variable on the twisted server without colliding, ie: a counter that increases by 1 each time a particular call is made to the Twisted server. Each client has a pb.Avatar attempting to update that global variable counter through a method call on the class extended on pb.Avatar. As the server is select-… [View More]

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com July 6, 2008

July 6, 2008

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[Twisted-Python] Peloton Distributed Service Application Engine
by Matthew Pontefract July 5, 2008

July 5, 2008

Hello Twisted Users I'd like to announce a new project called Peloton that may be of interest to some of you. Peloton is a distributed service application platform built in Python on top of Twisted. It's goals are: * To make trivial the process of writing, publishing a method * To provide all network interfaces on any relevant protocols and insulate the service writer from all of this * To provide simple, intuitive, modular mechanisms to transform the results of a method into a form … [View More]appropriate to the end user * To take care of managing services to ensure they stay alive, are distributed across a grid of computers and have requests distributed between them * To manage failure by re-issuing failed requests and managing the grid of nodes in such a way that, as far as is reasonably possible, the client is never troubled to know what lengths were gone to to return a result * To provide scalability * To provide inherent parallelisation for trivial problems * To provide an event bus accessible to server-side components and clients * To provide for easy (hot) upgrade of components and near zero downtime Why? I have worked in banks, small firms, big firms, supercomputing firms. I have worked in Java, in .NET, in Python. In almost all cases I was writing client-server systems where the application was event driven, needed to be resilient and would benefit from distribution for horizontal scalability. In all cases, making the results of server side operations available to as many different third party components as possible (via a multitude of protocols) would have been useful. And nowadays having data easily transformed into snippets of HTML or other formats, perhaps for AJAX apps etc is increasingly useful. Peloton is built to leverage the clarity, simplicity, power and rapid development times of Python and, using the reliable and solid Twisted core, provide the higher level features that give me all the above in a small and easy package. I'm not aiming to re-invent the wheel: I needed an event bus and, having used many, I've elected to use AMQP providers, RabbitMQ being a favourite. But this is all switchable because such functionality is managed by Peloton kernel plugins. Similar projects to Peloton exist: Pythomnic and Divmod-Mantissa to name two. They provide some, not all of the functionality or do things in ways that didn't quite suit me etc. Peloton is new, but I've implemented the ideas previously with the same technology at a supercomputing facility, and I presented the work at PyCon UK 2007. It works, people like it and its use is growing there. That's good enough for me to know that, at least for a section of the community, this is probably of interest. The future Peloton is very early at the moment and much is to come: a scheduler (cron for peloton) properly implemented distributed shared-state engine, different ways of deploying service code, better management tools, and more. Tight integration with Java could extend it's use into banking environments. A suite of services built on Peloton for job scheduling and management will provide another avenue to explore. It's all fun, and all interesting. It builds on the truly fantastic work of others and hopefully makes something novel and interesting. But that's for you to decide and I invite you to scout around the documentation, download the source code and give it a whirl. I'd love to hear what you think, know how you're using it and work with you to make it better. Where from? http://www.peloton-grid.net is the home of Peloton and hosts documentation and details of how to obtain Peloton. I hope it appeals and look forward to discussing with some of you about it. We can always meet on freenode.net, channel #peloton. Regards Matthew [View Less]

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