Mailman 3 May 2005 - Twisted

Re: [Twisted-Python] cleanup in twisted
by Joachim Boomberschloss 25 May '05

25 May '05

--- Jp Calderone <exarkun(a)divmod.com> wrote: > On Mon, 23 May 2005 05:12:49 -0700 (PDT), Joachim > Boomberschloss <boomberschloss(a)yahoo.com> wrote: > > > >--- Jp Calderone <exarkun(a)divmod.com> wrote: > >> On Mon, 23 May 2005 02:40:53 -0700 (PDT), Joachim > >> Boomberschloss <boomberschloss(a)yahoo.com> wrote: > >> > > >> >--- Bob Ippolito <bob(a)redivi.com> wrote: > >> >> > >> >> On May 22, 2005, at 8:46 AM, Joachim > >> Boomberschloss > >> >> wrote: > >> >> > >> >> > I just jotted down a little mechanism for > >> >> cleaning-up > >> >> > in Twisted, and I wanted to see if: > >> >> > 1. other people think it's needed > >> >> > 2. other people manage to use it > >> >> > > >> >> > What this does is enable one to define a > >> >> __cleanup__ > >> >> > method which gets call either when the > instance > >> is > >> >> > deleted, or when the reactor shuts down. It > can > >> >> return > >> >> > a dereffed that delays the shutdown. The > >> benefit > >> >> is > >> >> > being able to define communication-related > >> stuff > >> >> in > >> >> > the cleanup method, which is not so useful > to > >> do > >> >> in > >> >> > __del__. > >> >> > >> >> This is just begging for object leaks, because > >> >> __del__ disables > >> >> aspects of cyclic GC. > >> > > >> >Hmmpf. What does this mean, and is there a > simple > >> way > >> >of resolving it? > >> > > >> > >> If you construct a reference cycle which > contains > >> an object which has a __del__ method, the entire > >> cycle becomes "garbage" - Python cannot free any > of > >> the objects or call any of their __del__ methods. > >> Instead, it puts them into the gc module's > `garbage' > >> list and leaves them there forever. > >> > >> There's no simple way to resolve this (except > to > >> not implement __del__, of course ;). > >> > >> A non-simple way to resolve it is to use > weakref > >> callbacks instead of __del__. Weakref callbacks > >> have some nasty bugs in versions of Python older > >> than 2.3.5 (more, the further back you go), and > >> they're trickier to use than __del__. They don't > >> create garbage cycles, though. > >> > > > >Can you point me to an example of this (preferably > in > >Twisted)? Is this whole cleanup thing worth my time > >fixing it in your opinion? > > > > Twisted doesn't make use of it, due to the > instabilities in previous Python versions (which > Twisted still supports). > > Another technique I didn't mention is to move the > __del__ implementation off of the object which might > participate in a cycle and onto a subsidiary object. > Deferreds do this in Twisted 2.0. As a general > technique, this doesn't make much sense, since it > depends on knowledge of the structure of specific > object graphs (ie, you need to know where cycles > will form and where they will not). > > I'm not sure if it's worth the effort. I don't > exactly see the attraction of the functionality > being provided. I tend to find that explicit > cleanup is not overly burdensome. Perhaps you can > share some examples of how you see it being used? Well, the attraction is this: I ran into situations in which it is desirable for an object to do some communication-related cleanup when deleted, either when the program shuts down or when it is no longer referenced. For example, I have objects responsible for maintaining communication with some servers, and I want them to inform the server when they cease to maintain communication with it. This should be done either when the service is no longer necessary and the object (the maintainer) is deleted, or when the program shuts down, so basically, the functionality required is to be able to define communication-related stuff (i.e. things that aren't instantaneous and involve deferreds) to be done either when the object is deleted or when twisted shuts down. The latter is easy to do, but the former isn't, and come to think of it, my solution isn't good regardless of reference cycles, because, since the cleanup method is spawned from __del__, it has to do the cleanup instantaneously or the cleanup process won't be able to refer to the object at a later stage. Basically what is needed is to be able to defer the destruction of the object both at program shutdown, which is easy, and before object deletion, which I don't know how to do. Any thoughts (either about the attractiveness of the functionality or about how to achieve it)? Joe. __________________________________ Yahoo! Mail Stay connected, organized, and protected. Take the tour: http://tour.mail.yahoo.com/mailtour.html

2 3

[Twisted-Python] Handle Control-C
by Johannes Beigel 25 May '05

25 May '05

Is there a (preferred) way to handle breaks with Control-C? I'm aware of reactor.addSystemEventTrigger("before", "shutdown",...), but I'd like to do some stuff with a fully running reactor and then call reactor.stop() manually after some Deferreds come back. -jojo

2 1

[Twisted-Python] Twisted server connection loss with Mysql
by Raghul Jagan 25 May '05

25 May '05

Dear Friends, I am using a twisted server to connect the mysql database using "adbapi".When I start my server the connection to the mysql established and the run as a separate thread. Suppose If the database is restarted or there is a response delay, then the twisted server losses the connection and when I tried by quering the database it reports the error giving "Loss in mysql connection". I also tried using the twisted 2.0 version,but no way it does not connects automatically. Friends, Please give a solution for this problem. _________________________________________________________________ Get yourself a brand new Mobile. http://adfarm.mediaplex.com/ad/ck/4686-26272-10936-378?ck=BuyNewMobile Find,Compare & BUY IT NOW on eBay.in!

2 1

[Twisted-Python] Twisted as subprocess
by Nicola Larosa 25 May '05

25 May '05

I need to turn reactor.spawnProcess on its head. That is, I need to run a Twisted-based program as a subprocess, getting requests on stdin and giving responses on stdout. How do I hook up the protocol and the rest? It's going to be spawned by the snmpd daemon of net-snmp, via the pass_persist directive in snmpd.conf . -- Nicola Larosa - nico(a)tekNico.net How can I in five minutes shift a lifetime's hidden pain? -- Julia Fordham, Girlfriend, Porcelain, 1989

2 3

[Twisted-Python] Zope interfaces
by Grant McDonald 24 May '05

24 May '05

Hi All, I have just tried running my 1.3.0 application in 2.0.0 (rc2 I think?) and I received the following message: raise ImportError, "you need zope.interface installed (http://zope.org/Products/ZopeInterface/)" ImportError: you need zope.interface installed ( http://zope.org/Products/ZopeInterface/ <http://zope.org/Products/ZopeInterface/> ) >From this I understand that I need to install zope interfaces even if I don't use them, is that correct? (I imagine this is because other code in twisted uses them) ___________________________________________ Grant McDonald InfoComp Pty Ltd Programmer Level 1, 63 Market St, Wollongong Ph: (+61) 2 4298 9100 Fax: (+61) 2 4298 9199 Email: gmcdonald(a)infocomp.com ___________________________________________

6 5

Re: [Twisted-Python] cleanup in twisted
by Joachim Boomberschloss 24 May '05

24 May '05

--- Bob Ippolito <bob(a)redivi.com> wrote: > > On May 22, 2005, at 8:46 AM, Joachim Boomberschloss > wrote: > > > I just jotted down a little mechanism for > cleaning-up > > in Twisted, and I wanted to see if: > > 1. other people think it's needed > > 2. other people manage to use it > > > > What this does is enable one to define a > __cleanup__ > > method which gets call either when the instance is > > deleted, or when the reactor shuts down. It can > return > > a dereffed that delays the shutdown. The benefit > is > > being able to define communication-related stuff > in > > the cleanup method, which is not so useful to do > in > > __del__. > > This is just begging for object leaks, because > __del__ disables > aspects of cyclic GC. Hmmpf. What does this mean, and is there a simple way of resolving it? __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

4 3

[Twisted-Python] Weekly Bug Summary
by James Y Knight 24 May '05

24 May '05

Bug summary ______________________ Since 2005-05-09 15:24:45.360000: Bugs opened: 20 Bugs closed: 15 Total open bugs: 369 (+5) Urgent: 7 (-2) Bug: 149 (+2) Feature: 139 (+1) Wish: 74 (+4) New / Reopened Bugs ______________________ ==== Urgent ==== trial randomly exits prematurely for no good reason (1 week ago) CLOSED http://twistedmatrix.com/bugs/issue1036 opened by exarkun ==== Bug ==== [WEBSITE] http://twistedmatrix.com/documents/ has 1.3 documentation linked as current one (2 weeks ago) http://twistedmatrix.com/bugs/issue1029 opened by itamarst iocpreactor does not cancel pending operations on shutdown (1 week ago) http://twistedmatrix.com/bugs/issue1039 opened by PenguinOfDoom extra reference needed to show main window when using qtreactor (7 days ago) http://twistedmatrix.com/bugs/issue1041 opened by insanekane FTPFileListProtocol doesn't match lines on all FTP servers (3 days ago) http://twistedmatrix.com/bugs/issue1048 opened by orbitz [DOCUMENTATION] Changes to HOWTO index page (5 days ago) http://twistedmatrix.com/bugs/issue1043 opened by STemplar [WEBSITE] Link to API docs misleading (5 days ago) http://twistedmatrix.com/bugs/issue1045 opened by osuchw [WEBSITE] twisted-versions.txt should be in svn (1 week ago) http://twistedmatrix.com/bugs/issue1035 opened by dreid [WEBSITE] Unification of products and projects. (1 week ago) http://twistedmatrix.com/bugs/issue1034 opened by dreid ==== Feature ==== [CORE] Add blockingCallFromThread to twisted.internet.threads (5 days ago) http://twistedmatrix.com/bugs/issue1042 opened by spiv [WORDS] Update words to new cred APIs (1 week ago) CLOSED http://twistedmatrix.com/bugs/issue1031 opened by exarkun [WORDS] Improve IRCClient API (1 week ago) http://twistedmatrix.com/bugs/issue1030 opened by exarkun [WORDS] Update words to new PB API (1 week ago) http://twistedmatrix.com/bugs/issue1032 opened by exarkun [WORDS] Remove Words' use of deprecated t.web.widgets (1 week ago) http://twistedmatrix.com/bugs/issue1033 opened by exarkun iocpreactor needs to support TCP half-close (1 week ago) http://twistedmatrix.com/bugs/issue1038 opened by PenguinOfDoom [TRIAL] reactor interface predicate support in trial (1 week ago) http://twistedmatrix.com/bugs/issue1037 opened by exarkun ==== Wish ==== [XISH] xmlstream patch to get ready for TLS and SASL authenticators (3 days ago) http://twistedmatrix.com/bugs/issue1046 opened by tofu [WORDS, XISH] Can we add a NAMESPACE module (3 days ago) http://twistedmatrix.com/bugs/issue1047 opened by tofu Cred needs pam checker, and tehre is already one (5 days ago) http://twistedmatrix.com/bugs/issue1044 opened by liiwi Starting threads in a tac file blocks everything (7 days ago) http://twistedmatrix.com/bugs/issue1040 opened by exarkun Bugs Closed ______________________ ==== Urgent ==== trial randomly exits prematurely for no good reason (1 week ago) http://twistedmatrix.com/bugs/issue1036 opened by exarkun, closed by exarkun [DOCUMENTATION] [PATCH] epyrun doesn't like t.python.util.moduleMovedForSplit (5 months ago) http://twistedmatrix.com/bugs/issue828 opened by marienz, closed by jknight [DOCUMENTATION] epyrun dies with an internal error (1 month ago) http://twistedmatrix.com/bugs/issue973 opened by Ycros, closed by spiv ==== Bug ==== [CORE] Possible re-entrancy bug in LineReceiver.resumeProducing? (3 months ago) http://twistedmatrix.com/bugs/issue899 opened by spiv, closed by exarkun [WORDS] Use "Application-GUID" instead of "Application-Name" in _checkFileInvitation of msn.py (2 months ago) http://twistedmatrix.com/bugs/issue908 opened by cphsu, closed by exarkun [CONCH] Can't logout of an SFTP server (2 weeks ago) http://twistedmatrix.com/bugs/issue1027 opened by mkerrin, closed by z3p [TRIAL] trial's default timeout isn't enforced (2 weeks ago) http://twistedmatrix.com/bugs/issue1028 opened by warner, closed by exarkun HTTP multipart/form-data from Opera 7.52 raises error (10 months ago) http://twistedmatrix.com/bugs/issue649 opened by dotz, closed by jknight ==== Feature ==== [WORDS] Update words to new cred APIs (1 week ago) http://twistedmatrix.com/bugs/issue1031 opened by exarkun, closed by exarkun Pluggable Application loaders (8 months ago) http://twistedmatrix.com/bugs/issue720 opened by exarkun, closed by exarkun [PATCH] Unregister handlers for EventDispatcher (4 months ago) http://twistedmatrix.com/bugs/issue838 opened by ww, closed by exarkun twisted.web2 HTTP Server Enhancements (1 month ago) http://twistedmatrix.com/bugs/issue999 opened by srichter, closed by srichter Common Access Logging Observer for twisted.web2 (1 month ago) http://twistedmatrix.com/bugs/issue1000 opened by srichter, closed by srichter [WEB] mod_gzip type functionality for Twisted Web (22 months ago) http://twistedmatrix.com/bugs/issue104 opened by Nafai, closed by jknight [WEB] SCGI server protocol implementation (8 months ago) http://twistedmatrix.com/bugs/issue704 opened by fog, closed by jknight

1 0

[Twisted-Python] twisted.plugin plugin framework
by Nathaniel Haggard 23 May '05

23 May '05

1. What is/was the purpose of twisted.plugin? 2. "mypkg" is a directory containing __init__.py __init__.py contains: import twisted.plugin import zope.interface as z import twisted.plugin as p class Beta: z.implements(p.IPlugin) class Gamma: """This is the doc string""" __implements__ = p.IPlugin ----------------- Trying to load the package with getPlugins returns an empty generator as far as I can tell import twisted.plugin import mypkg l = twisted.plugin.getPlugins(twisted.plugin.IPlugin, mypkg) print dir(l) for i in l: ..... Actually twisted.plugin.getCache doesn't return anything for getPlugins to get. Am I setting up the package incorrectly?

2 1

Re: [Twisted-Python] cleanup in twisted
by Joachim Boomberschloss 23 May '05

23 May '05

--- Jp Calderone <exarkun(a)divmod.com> wrote: > On Mon, 23 May 2005 02:40:53 -0700 (PDT), Joachim > Boomberschloss <boomberschloss(a)yahoo.com> wrote: > > > >--- Bob Ippolito <bob(a)redivi.com> wrote: > >> > >> On May 22, 2005, at 8:46 AM, Joachim > Boomberschloss > >> wrote: > >> > >> > I just jotted down a little mechanism for > >> cleaning-up > >> > in Twisted, and I wanted to see if: > >> > 1. other people think it's needed > >> > 2. other people manage to use it > >> > > >> > What this does is enable one to define a > >> __cleanup__ > >> > method which gets call either when the instance > is > >> > deleted, or when the reactor shuts down. It can > >> return > >> > a dereffed that delays the shutdown. The > benefit > >> is > >> > being able to define communication-related > stuff > >> in > >> > the cleanup method, which is not so useful to > do > >> in > >> > __del__. > >> > >> This is just begging for object leaks, because > >> __del__ disables > >> aspects of cyclic GC. > > > >Hmmpf. What does this mean, and is there a simple > way > >of resolving it? > > > > If you construct a reference cycle which contains > an object which has a __del__ method, the entire > cycle becomes "garbage" - Python cannot free any of > the objects or call any of their __del__ methods. > Instead, it puts them into the gc module's `garbage' > list and leaves them there forever. > > There's no simple way to resolve this (except to > not implement __del__, of course ;). > > A non-simple way to resolve it is to use weakref > callbacks instead of __del__. Weakref callbacks > have some nasty bugs in versions of Python older > than 2.3.5 (more, the further back you go), and > they're trickier to use than __del__. They don't > create garbage cycles, though. > Can you point me to an example of this (preferably in Twisted)? Is this whole cleanup thing worth my time fixing it in your opinion? Joe. Yahoo! Mail Stay connected, organized, and protected. Take the tour: http://tour.mail.yahoo.com/mailtour.html

2 1

Re: [Twisted-Python] How to create a new service and listen on a new port?
by Eric Hsu 23 May '05

23 May '05

2005/5/23, mark <mark(a)junklight.com>: > Ah, > > my mistake for not reading properly. :-) Never mind : ) > > I guess one answer is to run AnotherService on port 2 from the start. [snip] > then both services will be running and you can just service both > ports. I am not sure quite what you are trying to do but from the > comments in your code why do you not simply send the confirm message > back via the FooServer? > Well, I need to create the AnotherService instances on many ports (port2, port3...) for each verified clients dynamically... Here is a scenario: * client1 sends the request to server on port1 * server verifies the client's request, and allocates a new port2 with the AnotherService binded to it, then tells the client1 that it has allocated port2 for it * client1 happily communicates with server on port2 and enjoys the AnotherService... * client2 sends another request to server on port1 * server verifies the request too, and allocates port3 for client2 * client2 communicates with server on port3 and enjoys yet another AnotherService instance... That's all I want to do... I'm reading this tutorial: http://twistedmatrix.com/projects/core/documentation/howto/application.html It seems that it's possible to have multiple services tie to one application? However, I would like to know is there a good way to dynamically create new services on new ports? best regards - Eric

1 0