Mailman 3 April 2010 - Twisted

[Twisted-Python] draft of an article on Twisted
by Jean Daniel 29 Apr '10

29 Apr '10

Hello, I have written an introductory article to Twisted, and I would be delighted to see it published on Linux Weekly News some day. It is available at: http://jdb.github.com/concurrent.html Here is the plan in brief: 1. what Twisted is: what "network framework" means, 2. what network concurrency is, 3. why "one socket in one thread" won't get you very far: Twisted is safer, faster and faster 4. what is the reactor, and how it interfaces with the kernel and the Twisted Protocols 5. what deferreds are (and how they are actually _not_ directly tied to the reactor) 6. Finally how to write Twisted code that looks sequential (with recap on yield and decorators) What I tried to do: - write for a developer audience who are not particularly expert in Python nor kernel internals. Python idioms are explained, and I try to clear the magic by unfolding the big ideas (this audience actually maps well my friends and colleagues), - include short, clear cut code snippets to nail the point, - short enough to fit in a brain cache but complete and precise enough so developers come out with an understanding of what is under the hood, - make the article "flow", by introducing the plan, connecting sections, using proper english :/ , Any comments welcome, and especially: - it might be too long and present too many things, maybe I should split it in parts, - correctness: I simplified the object model (the article mentions that the factories are out of scope...), but everything said should still be correct. Also I sometime take guesses at subject I am not an expert, with the intent to make a clear message: this is a thin line, - coherence with the Twisted jargon and existings docs, there may be terms that I use which should be substituted, - typos and proper english: I think lwn standards are pretty high for that matter, The pdf can't be attached, mailman complains that it is more than 40kB. The scripts are at http://github.com/jdb/jdb.github.com/tree/sources/concurrent/ The git manip for using your favorite editor on the sources is: git clone git://github.com/jdb/jdb.github.com.git git branch --track -b sources origin/sources vi concurrent.rst Thanks in advance !

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[Twisted-Python] XMLRPC server: nested handlers?
by Don Dwiggins 29 Apr '10

29 Apr '10

I have an XMLRPC server, currently with two subhandlers. One of them is getting quite large (over 120 "xmlrpc_" methods plus helpers), and I'd like to break it up into "sub-subhandlers". http://twistedmatrix.com/documents/current/web/howto/xmlrpc.html#auto2 says that you can do this "to arbitrary depths". It's not quite clear how to set this up, however. Before I start experimenting, I thought I'd ask if anyone has done this, and can show a bit of code for it. TIA, -- Don Dwiggins Advanced Publishing Technology

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[Twisted-Python] getting "connection per thread" behaviour
by Chris Withers 29 Apr '10

29 Apr '10

Hi All, I was asking about this on irc but had to leave in a hurry so thought I'd mail here... So, I have a pool of wsgi threads being run by Twisted's wsgi server that want to send stomp messages. The stomp client is Twisted-based (http://code.google.com/p/broadwick/source/browse/trunk/broadwick/messaging/…). I want to have as few stomp connections as possible, maxing out at one per thread. Bonus complications: - each wsgi thread has a logical transaction, that needs to marry up with the stomp logical transaction, so I can't just have one stomp connection per thread - I don't know how much overhead there is in creating the stomp connection, so I'd like to open as few as possible but keep them open and re-use them across wsgi requests. I found: http://pypi.python.org/pypi/txconnpool Anyone know how good that is and if it's useful here? All help gratefully received! Chris

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[Twisted-Python] Very interesting....
by Jason J. W. Williams 28 Apr '10

28 Apr '10

same example coded in eventlet, gevent, twisted, tornado, nodejs, thin+eventmachine http://gist.github.com/376416 (by @greut) Surprising…

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[Twisted-Python] multiple versions of twisted on same machine
by Pet 27 Apr '10

27 Apr '10

Hi, I'd like to upgrade twisted to the newest version and obviously first test if my application works fine with new version. What is the best (safest) way to do it? Thanks for help, Pet

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[Twisted-Python] SQLite3 gives error when using adbapi
by sleepd 25 Apr '10

25 Apr '10

I am try to use a in-memory sqlite db via adbapi, but sqlite gives error:" OperationalError: *no such table*: test ". how can I made it work? This is my test code: from twisted.internet import reactor from twisted.enterprise import adbapi def create(): db.runOperation("create table test(id)").addCallback(result).addErrback(error) def insert(): db.runOperation("insert into test(id) values(1)").addCallback(result).addErrback(error) def select(): db.runQuery("""SELECT * FROM test""").addCallback(result).addErrback(error) def result(l): print l def error(fail): print fail db = adbapi.ConnectionPool("sqlite3", database=":memory:") reactor.callLater(0.1, create) reactor.callLater(1, insert) reactor.callLater(2, select) reactor.run()

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com 25 Apr '10

25 Apr '10

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[Twisted-Python] twisted.web in 60 seconds...why aren't these on the frontpage of TM.com?
by Jason J. W. Williams 22 Apr '10

22 Apr '10

Hi Guys, Just been going through the twisted.web series JP put together (http://jcalderone.livejournal.com/tag/sixty%20seconds)...these are terrific. Turn the bottom one into serving a "Hello World" Resource and you've got a much simpler Hello World than the Tornado site (not to start a war on Tornado...their URL dispatch approach is pretty nice). Is there is a reason these aren't linked to on the frontpage of twistedmatrix.com...preferably with the short hello world above it? They're much more accessible than the Twisted Web tutorials under docs. -J

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[Twisted-Python] Getting a synchronous interface to a twisted reactor
by Andrey Fedorov 22 Apr '10

22 Apr '10

I'm trying to write a dead-simple interface for an IRC client library, like so: import simpleirc connection = simpleirc.Connect('irc.freenode.net', 6667) channel = connection.join('foo') find_command = re.compile(r'google ([a-z]+)').findall for msg in channel: for t in find_command(msg): channel.say("http://google.com/search?q=%s" % t) Working from the example in the docs<http://twistedmatrix.com/documents/current/core/howto/clients.html#auto5>, I'm running into trouble with the callbacks (the code is a bit lengthy, so I pasted it here <https://gist.github.com/e7e13f074a2691de6371>). The problem is that the call to channel.__next__ needs to be returned when the callback <IRCClient instance>.privmsg is called, there doesn't seem to be a clean option of doing that. I could try to use exceptions or threads, but that seems like the wrong thing here, is there a simpler (blocking?) way of using a twisted reactor that would make this possible? Cheers, Andrey On Wed, Apr 21, 2010 at 10:00 PM, César García <celord(a)gmail.com> wrote: > +1 Yes, it's great!! > > 2010/4/21 Kevin Horn <kevin.horn(a)gmail.com> > > This blog series is also totally rock-a-licious. >> >> http://krondo.com/blog/?page_id=1327 >> > > > > -- > http://celord.blogspot.com/ > > _______________________________________________ > Twisted-Python mailing list > Twisted-Python(a)twistedmatrix.com > http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > >

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[Twisted-Python] twistd and init.d
by Don Schoeman 22 Apr '10

22 Apr '10

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