Mailman 3 May 2010 - Twisted

[Twisted-Python] Comparing "Stackless Python + Nonblocking Stackless Modules" with Twisted.
by Peter Cai 09 May '10

09 May '10

Today, a guy gave me an URL http://code.google.com/p/stacklessexamples/wiki/StacklessNonblockModules It's a replacement of standard python socket module. What make it different is that this module only blocks a tasklet, not an entire Python thread. With this module and stackless python, theoretically, we can build a high concurrency network application framework which has a programming style close to traditional multi-thread module. The guy who gave me that URL asked a question, "Which style is better? The Twited's event-driven style or the imaginary one?" What do you think about it? Of course, twisted is an mature framework we can trust, but doesn't the imaginary one also have pros? -- look to the things around you,the immediate world around you, if you are alive,it will mean something to you ——Paul Strand

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[Twisted-Python] SQLAlchemy and Twisted
by Doug Farrell 09 May '10

09 May '10

Hi all, I've been doing some searching about how to get SQLAlchemy and Twisted working together in a Twisted application. Though I've found a lot of information, I haven't seen (or figured out) a good working solution or definitive answer. The most promising one I've run across concerns running the SQLAlchemy queries in a separate process (rather than a separate thread) and communicating the queries between the Twisted application in one process and the SQLAlchemy application in another. Does anyone have any good pointers, suggestions, ideas, links to how I might go about setting something like this up? Here's a couple questions that come to mind: 1) Would the SQLAlchemy process also be a Twisted application with all the queries running as deferreds in the main thread, and blocking? 2) How would the Twisted process communicate with the SQLAlchemy process, using something like XMLRPC, calling methods to perform the queries? Or would the XMLRPC methods convey something more generic like SQL? Thanks in advance for any help! Doug

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[Twisted-Python] win32com client in a twisted thread
by Don Dwiggins 09 May '10

09 May '10

I'm running a Windows service with Twisted (xmlrpc), and I've run into an odd case. In a recently implemented method, I create a COM object with win32com.client.Dispatch (using a COM DLL that's part of the overall application) and make a couple of calls on it, getting a return value. This works well, except that the COM object calls a web service, which can take a few seconds, so I wanted to defer it. When I isolate it into a function, and call that with deferToThread, the thread appears to die. I tried putting the Dispatch call in the mainline, then passing it to the function -- this kills Python (not too surprising really). I'm also using dbapi, so I tried it using runInteraction, with no better luck. For what it's worth, here's the code: > command = Dispatch('APTAuthorize.clsAuthorizeBatch') > model = command.SetupFromConnParms(db['DSN'], db['UserName'], db['Password']) > # The returned value is a tuple: the model followed by the params > model = model[0] > model.PaymentAdjustment = "P" > model.BatchId = rsltDict['lPaymentBatchId'] > model.ShowProgress = True > model.AuthorizationType = "CCD" > command.Execute(SecurityCode) Putting logging statements in, I found that it died during the first call to "command". (With no error message or other indication.) Any thoughts or useful information appreciated, -- Don Dwiggins Advanced Publishing Technology

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[Twisted-Python] Release again in June?
by Jonathan Lange 09 May '10

09 May '10

Hello everyone, Some of you may recall that the last Twisted release, Twisted 10.0.0 took place in early March of this year. It was my intent then to release 10.1.0 in early June, thus moving us toward a regular release cycle. I am still keen to do this. Does anyone have any thoughts, objections or recommendations? Thanks, jml

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Re: [Twisted-Python] [#24487862] Re: SQLAlchemy and Twisted
by Phil Mayers 09 May '10

09 May '10

Erm... Someone appears to have subscribed a ticketing system w/ autoresponer to the Twisted mailing list; any chance a list admin could unsubscribe it? The email below claimed a "From:" of the m/l but a "Reply-To:" of support(a)mpcustomer.com On 05/09/2010 10:49 AM, twisted-python(a)twistedmatrix.com wrote: > Hello, > > This is an automated response to inform you that your question has been entered into our system, and will be reviewed shortly. Your ticket has been submitted into the "General Support" department. > > We will respond to you as soon as possible. > > ============== > Please keep this information, and use it when refering to your ticket: > > Ticket subject: Re: [Twisted-Python] SQLAlchemy and Twisted > Ticket number: 24487862 > Ticket link: https://secure.mpcustomer.com/ticket.php?ticket=24487862 > Ticket body: On 05/09/2010 07:07 AM, Daniel Griffin wrote: >> If you let SQLAlchemy block twisted would there be any impact besides >> performance? > > Depends how long it blocks for, and what else your process is doing. > > With the reactor blocked: > > * no socket reads or accepts can be done > * no callLater or LoopingCall can be scheduled > > ...and so on. > > If you've only got a small number of clients and no time-based > scheduling and you're only blocking for a short time (tens or hundreds > of milliseconds, say) it may be tolerable. > > If the server has a lot of clients, or needs to accept new ones in a > timely fashion, or has time-based work to do, and your blocking might go > on for a while, it's probably not tolerable. > > I'd avoid it personally (but then I'm utterly unconvinced by ORMs) and > stick to using SA in a thread as your SQL query layer. > > _______________________________________________ > Twisted-Python mailing list > Twisted-Python(a)twistedmatrix.com > http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > ============== > > >

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com 08 May '10

08 May '10

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[Twisted-Python] How do I get xUnit output from trial for Hudson?
by Chris Withers 08 May '10

08 May '10

Hi All, How can I get trial to emit output that makes Hudson happy? cheers, Chris

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[Twisted-Python] IRCClient: Handle lines that are too long for the server
by Adrian Overbury 07 May '10

07 May '10

So, there's a todo item in IRCClient, to handle lines that are longer than the RFC maximum length (510 characters including the sender, recipient and command, plus `\n` and `\r`). I had thought to have a method sitting between the IRCClient.sendLine() and the method which actually calls out to the transport to put the data on the wire. The default method would simply pass the message through, sending it on to the server as is, to be inevitably truncated at the other end. The documentation could contain examples of possible implementations, such as one which splits the message up into multiple messages and sends them on, and one which truncates the message. For example, IRCClient could contain the method: def longLineHandler(self, message): return message This would necessitate adding a check to IRCClient to see what is returned by longLineHandler(). I would suggest that it would accept a single `str` or a list of `str`s as valid input, and anything else will either make the sendLine() method do nothing and just silently return, or will raise an exception. If it returns silently, it would allow the user-defined longLineHandler() to implement splitting a message up into multiple messages by either returning a list of `str`s, or by calling self.sendLine() themselves and then returning None to have the original sendLine() return silently. For example, if the user overrode longLineHandler() and made it split the message into multiple messages, in peudocode it could go like this call self.sendLine call self.longLineHandler with parameter 'message' is message longer than 510 characters? yes: split up command prefix and payload use textwrap module to split payload into multiple messages no longer than "510 - length of command prefix" prepend command prefix to each message and call self.sendLine with each one return None no: return message did self.longLineHandler return None? yes: return did self.longLineHandler return a list of `str`? yes: for each `str` in list: call self.reallySendLine or place on message queue no: call self.reallySendLine or place on message queue The user might also want to have their longLineHandler raise an exception if the line is too long, or they might want to have it make the lines shorter than 510 characters total, or strip control codes if they're too long to try and shorten it... there's a number of different use cases for this, so I'm trying to build a framework for it that's flexible enough to handle more or less anything. I'd value any comments anyone has on this. I also have an enhancement ticket open in the bug tracker, ticket #4416. -- Adrian

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[Twisted-Python] EuroPython 2k10: planned sprint days?
by Laurens Van Houtven 07 May '10

07 May '10

Hey, Can anyone tell me which sprint days (if any) Twisted is organizing something on? If nothing is planned yet, does anyone have any preferences? Thanks, Laurens

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[Twisted-Python] multiline log entries
by Pet 06 May '10

06 May '10

Hello! Is it possible to print multiline debug messages into log? If print a query it looks like this 2010-05-06 10:10:07 [HTTPChannel,0,192.168.2.15] SELECT * 2010-05-06 10:10:07 [HTTPChannel,0,192.168.2.15] FROM foo AS a 2010-05-06 10:10:07 [HTTPChannel,0,192.168.2.15] JOIN bar AS b ON a.id = b.id 2010-05-06 10:10:07 [HTTPChannel,0,192.168.2.15] WHERE a.id = 1 2010-05-06 10:10:07 [HTTPChannel,0,192.168.2.15] ORDER BY id DESC 2010-05-06 10:10:07 [HTTPChannel,0,192.168.2.15] LIMIT 1; it would be more practical to have only the query without timestamp on other things Thanks!

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