Mailman 3 April 2006 - Twisted

[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com April 30, 2006

April 30, 2006

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[Twisted-Python] planet.twistedmatrix.com
by Mary Gardiner April 29, 2006

April 29, 2006

Is anyone able to take this over? It would make the most sense, I think, to host it where the main website is hosted. As soon as someone volunteers, I'll pass on all necessary files and from there it's just a question of setting up a cron job. -Mary

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Re: [Twisted-Python] The End, also: documentation
by Ed Suominen April 29, 2006

April 29, 2006

Mary Gardiner wrote, utterly without influence from burning > This is my resignation as Twisted's lead documentation person. > > Rest assured I'm not resigning due to any subset of: burning > disillusionment, raging anger, or rampaging untreated mental illness. > Rather, I have a bundle of other projects, and they're increasingly > unrelated to Twisted, which means that I'm not using it for my own > projects, and, sadly, I don't have the energy left over to task switch … [View More]> into an unrelated project enough to lead part of it. > > I'm also, as it turns out, much more interested in reviewing and/or > editing documentation than I am in writing it. The upside of this is > that I'll continue to make myself available as a reviewer of > documentation patches and/or an editor, if needed. Feel free to assign > bugs on this basis. (I will probably not be reading the mailing list, > but I don't make myself difficult to find on IRC.) I will unassign other > bugs from myself soon. > > This obviously leaves gaping holes in the greater Twisted universe for > people anxious to advertise the glory of Twisted to the admiring masses. > Do submit some documentation patches... It also leaves a vacancy for > someone who is willing to be caretaker for the documentation as a whole, > fixing minor bugs, farming out work and rearranging things according to > their taste. Apply here, I suspect :) Mary, this Twisted user for one really appreciates the efforts you've put forth. Indeed, as one of the biggest complainers about Twisted's docs, I probably appreciate those efforts more than many users. (That sounds backwards until you think about it for a while, like a lot of legal language.) I'm thinking about suggesting (gasp!) myself as your replacement. The logical, responsible part of my brain is telling me that I'm insane for doing this. But there's another part of my brain that has an illogical, probably unhealthy fascination with Twisted and is raising its hand and squirming on the uncomfortable wooden schooldesk chair with those huge uncomfortable screw heads sticking out, yelling "Call on me! Call on me!" As a registered patent agent (http://eepatents.com), I do a lot of writing as part of my work and bill quite a bit per hour for doing so. (Here that logical, responsible part is screaming, "So WHY do you want to do more writing for FREE?") I have complained and whined about the, shall we say "mixed," state of Twisted's docs for years now on #twisted and am intrigued by the idea of putting my mouth (dictation) where my mouth (complaints) is. Plus, (branch) commit access would be kind of cool for writing those docstrings where I just can't stand seeing those glaring holes right below "def" or "class"... It goes without saying (but I'll say it anyway) that there is and would be absolutely no professional relationship between me and the Twisted project. (Most free software types aren't all that enamored with patents, anyhow...) I have kind of enjoyed the decidedly unprofessional relationship that has developed on #twisted, though. Comments welcome. Any positive ones will likely be viewed with suspicion and will raise pangs of regret at my making this rash posting. The negative ones will likely be viewed with relief, at least by the aforementioned logical, responsible part... Best regards, Ed Suominen Logical, responsible patent agent Inexplicably passionate Twisted dabbler [View Less]

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[Twisted-Python] Crash when using XmlRPC during reactor shutdown
by David Anderson April 29, 2006

April 29, 2006

Hi, I have been experiencing a crash when trying to use the XmlRPC query subsystem while the reactor is shutting down. The context of it is that my twisted application talks to an upstream server using XmlRPC. When it comes online, it registers, and when it goes offline, it should unregister itself, using a simple XmlRPC query. So, I figured the natural place to put the notifications were in the startService and stopService methods, that get called at just the right time. startService is … [View More]not a problem, and works fine. for stopService, I made the method return the XmlRPC Deferred, so that the reactor would wait until request completion before continuing the shutdown. The thing is, with this scheme Twisted dumps an exception during shutdown, because the XmlRPC Deferred gets fired twice. I've reproduced this behaviour with a minimal application: **************************************************************** **************************************************************** from twisted.application.service import Service from twisted.python import log from twisted.web.xmlrpc import Proxy from twisted.application.service import Application, IServiceCollection from twisted.internet import reactor, defer class TestXmlRpcService(Service): def startService(self): log.msg("Starting service") reactor.callLater(0, reactor.stop) def stopService(self): def handle_success(res): log.msg("Unregistration successful, but reactor will now crash") return True def handle_error(e): log.msg("Unregistration failed...") return False log.msg("Calling XmlRPC backend (and crashing)") p = Proxy('http://natulte.net/pub/fgs/RPC2.php') defer.setDebugging(True) # Call any old method, this is just a proof of concept d = p.callRemote('fgsd.register', "00000000000000000000000000000000", "bleh") d.addCallbacks(handle_success, handle_error) return d service = TestXmlRpcService() application = Application("proxy") service.setServiceParent(application) **************************************************************** **************************************************************** If you run that with `twistd -n -l- -y test.tac`, you should see the crash immediately. I know that patients shouldn't give diagnostics about their problems to the doctor, but nevertheless, examining the exception log, I believe I know what the problem is. - When stopService returns a Deferred, the reactor stops the shutdown and adds callbacks to the Deferred, to resume shutdown at the right time. - The XmlRPC query succeeds, and fires the Deferred. It walks right down the notification chain, and eventually trips the reactor's callback. - The reactor, within the callback, resumes shutdown, and calls disconnectAll to kill all active connections. - At this point, the XmlRPC query still has its socket open, and so gets notified that the connection was lost. It attempts to fire our Deferred's errback to notify of this, and foom, AlreadyCalledError. If this makes sense, the resolution might be simple: close the transport connection before firing the deferred, so that the reactor can't kill the connection and trigger the double-call. The other option would be to include a flag in the xmlrpc query object, to avoid double-firing in this (admitedly corner-case) situation. Does all that make sense? And, of course, does anyone have an idea of a workaround I could use in the meantime? As I'm shutting down the service anyway, the exception is not really a problem in itself, it's just a little unclean to have an exception dump in the logs at each shutdown. Thanks in advance (and already, for Twisted :-), - Dave. [View Less]

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[Twisted-Python] conch and cftp
by Manlio Perillo April 29, 2006

April 29, 2006

Hi. There is a reason for conch (and cftp) script not working on Windows? Traceback (most recent call last): File "C:\Python2.4\Scripts\conch.py", line 20, in ? from twisted.conch.scripts.conch import run File "C:\Python2.4\lib\site-packages\twisted\conch\scripts\conch.py", line 18, in ? import os, sys, getpass, struct, tty, fcntl, base64, signal, stat, errno File "C:\Python2.4\lib\tty.py", line 5, in ? from termios import * ImportError: No module named termios Moreover … [View More]

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[Twisted-Python] Naming test methods constructed with deferredGenerator - is it possible?
by Marcin Kasperski April 28, 2006

April 28, 2006

In my trial tests I have a few test methods constructed using deferredGenerator idiom. Something like that: def testSomething(self): # ... do something yield defer.waitForDeferred(someDeferred) # ... do something yield defer.waitForDeferred(otherDeferred) # ... do something testSomething = defer.deferredGenerator(testSomething) Let's write clean code and works perfectly. ... Almost. The problem is that in the verbose test output I get <… [View More]

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[Twisted-Python] SMTP client with authentication
by Mustafa Sakalsiz April 28, 2006

April 28, 2006

Hi, I try to implement a simple smtp client, but my smtp server requires authentication. Is there a client sample which accomplishes the basic or plain smtp authentication. Thanks, Saki

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[Twisted-Python] Twisted's ability to handle many open connections.
by Terry Jones April 27, 2006

April 27, 2006

I'm completely new to Twisted. As I understand it, a Twisted server runs as a single process - no forking, no threads. To me that implies that select (or poll or pselect, etc) is being heavily used to feed data to Deferreds. If that's the case, how does Twisted (portably) allow for a large number of file descriptors? I'm considering using Twisted for a project. Twisted would front requests from the web, but also from (e.g.) remote command line applications via an API. These latter … [View More]

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Re: [Twisted-Python] Twisted's ability to handle many open connections.
by Terry Jones April 26, 2006

April 26, 2006

Hi Matt. Thanks for your answer too. >>>>> "Matt" == Matt Goodall <matt(a)pollenation.net> writes: >> If that's the case, how does Twisted (portably) allow for a large number of >> file descriptors? Matt> As you recognised, Twisted uses a select loop so I'm not quite sure what Matt> your question means. You get to it below. Matt> You will need to understand event driven programming to scale up, Matt> otherwise you're likely to block the … [View More]

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Re: [Twisted-Python] Twisted's ability to handle many open connections.
by Terry Jones April 26, 2006

April 26, 2006

>>>>> "glyph" == glyph <glyph(a)divmod.com> writes: glyph> That's more or less accurate. It sounds like you understand this, glyph> but because I can never repeat it enough: Deferreds don't do glyph> anything magic or get involved with select() directly Ok, got it. glyph> On Windows, there is a reactor that supports a maximum of 63 glyph> concurrent events (assuming your process has no windows open). On glyph> UNIX the default reactor is still select(… [View More]

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