Mailman 3 December 2011 - Twisted

[Twisted-Python] regarding classes and functions in twisted.python.reflect
by moses dsouza 29 Dec '11

29 Dec '11

Hi I'm new to twisted. While was working on bug #5385 I noticed that classes AccessorType, PropertyAccessor, Accessor and Summer were rarely used elsewhere in the code. Similaryly many functions exists which are unused. Do we need these functions and classes? I do understand that the purpose t.python.reflect provides "Standardized versions of various cool and/or strange things that you can do with Python's reflection capabilities." but I feel if we could remove things that we don't need we could make the code base smaller and move towards making twisted more efficient. Looking forward to your views regards moijes12

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[Twisted-Python] [ANNOUNCE] txWS 0.7
by Corbin Simpson 28 Dec '11

28 Dec '11

Hi, A new version of the surprisingly-popular txWS is now available. You can grab it from PyPI (http://pypi.python.org/pypi/txWS) or from source on Github (https://github.com/MostAwesomeDude/txWS). As before: txWS is a small, single-module library for augmenting Twisted with WebSockets support. Unlike other approaches, txWS has a minimalist philosophy and only provides enough WebSockets machinery to wrap server factories. Notably, txWS does not provide a WebSockets client. New in this release: Underlying protocols using writeSequence() are no longer broken with txWS, Chrome 16 and other RFC 6455-compatible browsers are now supported, and there were a couple other cleanups not really worth mentioning. A couple people have asked about better examples. Somebody actually sent me a very full example (https://gist.github.com/1380305) which is probably a bit too big for docs, but is definitely a real-world bit of usage. I'll see about getting some complete server examples all lined up for people to use. As always, feedback is welcome. ~ C. Oregon State University Open Source Lab -- When the facts change, I change my mind. What do you do, sir? ~ Keynes Corbin Simpson <MostAwesomeDude(a)gmail.com>

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[Twisted-Python] Question : Combining wokel XMPP and twisted.internet.serial
by bino oetomo 25 Dec '11

25 Dec '11

Dear All .. A year ago, I need send some defined message to a jabber conference. The message content will depend on a "button-press". My trick is to use ttyctrl (http://ttyctrl.sourceforge.net/). So basicaly my "system" is builded from several parts: 1. TTYCTRL : I made some small python XMLRPC client script, that will send a msg to my local twisted server 2. Twisted server, contain : a. an XMLRPC server b. XMPP Client ... use to send msg to remote jabber conference room I made a pastebin of that twisted script at : http://pastebin.com/iSRVZNwS With that script the flow alway one-way only : serial====>Twisted_XMLRPC--->Twisted_XMPP=====>Jaber Now I need to do something different, since it's hard to find a Board with RS232 onboard. I Need to replace TTYCTRL with Arduino MCU. Arduino will Send serial data to my PC. So I'll need my twisted to able to receive data via serial There will also incoming XMPP msg from Jabber that will need to be send to arduino via Serial port. so the flow will be like : serial<====>Twisted_Serial<--->Twisted_XMPP<=====>Jaber My question is, How to make : 1. twisted.internet.serial to send data via an instance of XMPP client ? and 2. my EchobotProtocol.onMessage (see pastebin), to write data to the same serial port used by Point#1 above. Sincerely -bino-

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com 24 Dec '11

24 Dec '11

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Re: [Twisted-Python] [Twisted] #5437: sys.settrace(None) in process.py raises RuntimeError in debugger
by Bob Novas 21 Dec '11

21 Dec '11

Well, what wing's debugger does is to raise RuntimeError, and NOT CONTINUE to execute that path. So the child never runs. That's bad! What more can I say? I have to comment out that line every time I run on a new installation if I want to debug in linux (Windows doesn't go down that code path). Bob > -----Original Message----- > From: Twisted [mailto:trac@twistedmatrix.com] > Sent: Tuesday, December 20, 2011 4:40 PM > Subject: Re: [Twisted] #5437: sys.settrace(None) in process.py raises > RuntimeError in debugger > > #5437: sys.settrace(None) in process.py raises RuntimeError in debugger > --------------------------+--------------------------------------------- > --------------------------+---- > Reporter: BobNovas | Owner: BobNovas > Type: defect | Status: new > Priority: normal | Milestone: > Component: core | Keywords: settrace, process > Branch: | Branch_author: > Launchpad_bug: | > --------------------------+--------------------------------------------- > --------------------------+---- > Changes (by exarkun): > > * owner: => BobNovas > * milestone: regular-releases => > * branch_author: BobNovas => > > > Comment: > > The ''regular-releases'' milestone is for release automation. The ''author'' field > is for svn branch authorship. I've unset these two fields. > > I'm think the intent of the `sys.settrace(None)` call is to disable debuggers. It > does this because there's very little left to do before the Python process is going > to be replaced by a new process (which will not be debuggable using the trace > hook) and because there are two different Python processes being debugged at > that point in the code, because of the `os.fork` call which has succeeded just > beforehand. > > Does Wing have some way to meaningfully debug two processes > simultaneously, where the second is created using `os.fork` in the first? > If not, then there's no use in removing the `sys.settrace(None)`, because it will > just break in some other way. > > I have very little experience with Wing's debugger, so I don't know what it's > possible to do in this case. I'm also not really sure what a Wing debugger user > (ie you :) expect to happen. > > Can you shed some more light on this? Thanks. > > -- > Ticket URL: <http://twistedmatrix.com/trac/ticket/5437#comment:1> > Twisted <http://twistedmatrix.com/trac/> Engine of your Internet

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Re: [Twisted-Python] deferred generators in inline callbacks
by Andrew Francis 21 Dec '11

21 Dec '11

Message: 2 Date: Tue, 20 Dec 2011 19:14:10 -0000 From: exarkun(a)twistedmatrix.com Subject: Re: [Twisted-Python] deferred generators in inline callbacks To: Twisted general discussion <twisted-python(a)twistedmatrix.com> Message-ID: <20111220191410.2164.1501005671.divmod.xquotient.42(a)localhost.localdomain> Content-Type: text/plain; charset="utf-8"; format="flowed" On 06:24 pm, alex.kirp(a)gmail.com wrote: A>Hi. A> A>I have a question about inline callbacks usage. E>You're basically looking for coroutines - ie, context switching across E>multiple stack frames (from inside some_generator through do_stuff out E>to the implementation of inlineCallbacks). E>There are several coroutine libraries for Python. Greenlets is probably E>the most popular. You can use it with Twisted, if you want. I believe Christopher Armstrong a long time ago had corotwine. However if you download the greenlet package and stackless.py, it is not hard to make them interoperate with Twisted. Here is a recent example of how I use them: http://wp.me/pdqoq-3Y Cheers, Andrew

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[Twisted-Python] deferred generators in inline callbacks
by Алексей Кирпичников 20 Dec '11

20 Dec '11

Hi. I have a question about inline callbacks usage. Let's assume I have an iterator that works synchronously. I want to wrap this generator to work asynchronously in threads: def some_generator(): cursor = make_iterator() # cursor's 'next' method uses some nasty blocking I/O while 1: yield deferToThread(cursor.next) Next, I want to asynchronously iterate over this generator in inlineCallbacks semantics. I should say: @inlineCallbacks def do_stuff(): for item in some_generator(): try: real_item = yield item # do stuff with real_item except StopIteration: break It somewhat annoys me that I should always convert item to real_item so inlineCallbacks can properly asynchronize my code. I also need to implement StopIteration myself :( Is there any easier way to do this in Twisted? Thanks in advance! -- Alex

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com 17 Dec '11

17 Dec '11

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[Twisted-Python] (no subject)
by PETA Antonio Silvio 16 Dec '11

16 Dec '11

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[Twisted-Python] MemoryError in twisted.internet.abstract.FileDescriptor
by Augusto Mecking Caringi 15 Dec '11

15 Dec '11

Hi! I'm writing a software using Python Twisted with the following architecture: [server]<->[providers] The providers (that can be thousands) send events to the centralized server, usually we have a few events per minute for each provider, but a burst of events can happen. So I write a test provider to simulate the sending of millions of events without any delay, via a thread like that: def stressTestTask(): time.sleep(1) c = provider_reference for i in range(1000000): event = c.createTestEvent() reactor.callFromThread(c.transport.write, event) Then I started to analyze memory consumption while running this test code, and I find out that the memory consumption grows to gigabytes and finally a MemoryError exception raises: Traceback (most recent call last): File "/usr/lib/python2.5/site-packages/twisted/python/log.py", line 84, in callWithLogger return callWithContext({"system": lp}, func, *args, **kw) File "/usr/lib/python2.5/site-packages/twisted/python/log.py", line 69, in callWithContext return context.call({ILogContext: newCtx}, func, *args, **kw) File "/usr/lib/python2.5/site-packages/twisted/python/context.py", line 118, in callWithContext return self.currentContext().callWithContext(ctx, func, *args, **kw) File "/usr/lib/python2.5/site-packages/twisted/python/context.py", line 81, in callWithContext return func(*args,**kw) --- <exception caught here> --- File "/usr/lib/python2.5/site-packages/twisted/internet/selectreactor.py", line 146, in _doReadOrWrite why = getattr(selectable, method)() File "/usr/lib/python2.5/site-packages/twisted/internet/tcp.py", line 177, in doWrite return Connection.doWrite(self) File "/usr/lib/python2.5/site-packages/twisted/internet/tcp.py", line 428, in doWrite result = abstract.FileDescriptor.doWrite(self) File "/usr/lib/python2.5/site-packages/twisted/internet/abstract.py", line 199, in doWrite self.dataBuffer = buffer(self.dataBuffer, self.offset) + "".join(self._tempDataBuffer) exceptions.MemoryError: After a search, I found this ticket: http://twistedmatrix.com/trac/ticket/3682 And I think that this is exact my problem. What's the best solution? Apply the patch attached on this ticket, moving to a producer/consumer approach, or any other idea? Thanks! -- Augusto Mecking Caringi

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