Mailman 3 May 2008 - Twisted

[Twisted-Python] Maximum recursion depth reached
by Steve Freitas May 9, 2008

May 9, 2008

Hi all, I'm hitting the recursion limit in my code (well, somewhere inside Twisted, that is), and I'd appreciate any insight as to why. I wouldn't think what I'm doing -- returning a callback from method A which calls method B, which then in turn calls method A again -- would be controversial, since I'd assume Python would be letting go of the stack for method A, but I guess there's more to it than that. Code demonstrating the issue follows. Running it results in: File "/usr/lib/python2.5/… [View More]

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Re: [Twisted-Python] Twisted Presentation Materials...
by Andrew Francis May 9, 2008

May 9, 2008

Hi Glen: > This is a good opportunity to decompose Twisted into >its core elements... kinda how it would be presented >to mathematics folks. If I don't screw it up, it might >even be useful to a broader audience trying >to figure out what Twisted is and the kinds of problems it addresses. In my PyCon 2008 talk, "Adventures," I have one slide that categorises Protocols, Deferreds, Callbacks, and the Reactor. I think those are the key components of Twisted. For greater … [View More]

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[Twisted-Python] Twisted Presentation Materials...
by Glenn H Tarbox, PhD May 8, 2008

May 8, 2008

Scary thought... I am giving a talk on Twisted at Sage Developer Days. Its a fairly broad audience WRT levels of Pythonism.. but with other talks having titles like "Cylindrical Algebraic Decomposition", I doubt complexity in and of itself is a concern. This is a good opportunity to decompose Twisted into its core elements... kinda how it would be presented to mathematics folks. If I don't screw it up, it might even be useful to a broader audience trying to figure out what Twisted is and … [View More]

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[Twisted-Python] [ANN] Foolscap-0.2.6 released
by Brian Warner May 7, 2008

May 7, 2008

I've just finished releasing Foolscap-0.2.6, the next-generation remote object protocol, intended as the successor to Perspective Broker. This release contains more logging improvements, including the long-awaited "incident-based logging" system (which dumps "black box" records of recent events when something bad happens), and several bugfixes. The full release notes are attached below. Tarballs can be obtained from foolscap.lothar.com and from PyPI. All releases are signed by my GPG public … [View More]key: 0x1514A7BD . http://pypi.python.org/packages/source/f/foolscap/foolscap-0.2.6.tar.gz#md5… http://pypi.python.org/packages/source/f/foolscap/foolscap-0.2.6.zip#md5=1b… For documentation, bugs, and patches, please visit http://foolscap.lothar.com/trac . share and enjoy, -Brian * Release 0.2.6 (06 May 2008) ** Compatibility All releases between 0.1.3 and 0.2.6 (inclusive) are fully wire-compatible. The saved logfiles produced (by e.g. 'flogtool tail --save-to' and the log-gatherer) in 0.2.6 and beyond are not readable by tools (e.g. 'flogtool dump' and 'flogtool filter') from 0.2.5 and earlier. FURLs which contain "extensions" (described below) will not be tolerated by foolscap 0.2.5 or earlier. If, at some point in the future, we add such extensions to published FURLs, then such an application will require foolscap-0.2.6 or later to interpret those FURLs. ** Logging Changes *** "Incident" Logging This release finally implements the "strangeness-triggered logging" espoused in doc/logging.xhtml . By giving the foolscap logging code a directory to work with, the logging system will automatically save a compressed pickled logfile containing the messages that lead up to sufficiently-severe log event. The docs explain how to control what "sufficiently-severe" means. These events are retrievable through the logport, although no tools have been written yet to actually extract them. They are also retrievable by using 'flogtool dump' directly on the incident files. *** 'flogtool as a subcommand The implementation of the 'flogtool' executable has been rearranged to make it possible to add a 'flogtool' subcommand to some other executable. *** 'flogtool filter' now has --above LEVEL and --from TUBID options *** 'flogtool dump' has --rx-time option, also shows failure tracebacks *** gatherer: don't add erroneous UTC-implying "Z" suffix to filename timestamps *** 'flogtool tail': don't add spurious "0" to timestamps ** constraints no longer reject ('reference',) sequences The foolscap/banana serialization protocol responds to sending two separate copies of the same object in the same callRemote message by emitting one serialized object sequence and one 'reference' sequence: this is the standard way by which cycles are broken in the serialized data. Unfortunately, the wire-level constraint checkers in 0.2.5 and earlier would reject reference sequences with a Violation exception: if they were expecting a tuple, they would reject anything else, even a reference sequence that pointed at a tuple. Worse yet, python's normal constant-object folding code can produce shared references where you might not expect. In the following example, the two tuples are identical objects (and result in a 'reference' sequence on the wire), despite the programmer having typed them separately: rref.callRemote("haveTwoTuples", (0,1), (0,1) ) Foolscap-0.2.6 now allows reference sequence in all wire-level constraint checks, to avoid this false-negative Violation. The post-deserialization check will still enforce the constraint properly. It just does it late enough to be able to tell what the reference points to. ** Twisted/pyopenssl compatibility *** compatible with Twisted-8.0.x Some unit test failures under Twisted-8.0.x (the most recent release) were fixed: tests now pass against Twisted-8.0.x, and a buildbot is used to make sure compatibility is maintained in the future. *** incompatible with pyOpenSSL-0.7 An incompatibility has been discovered with the most recent version of PyOpenSSL. pyopenssl 0.6 works correctly, but pyopenssl 0.7 causes modern versions of Twisted (both 2.5.x and 8.0.x) to follow a code path that breaks the Foolscap unit tests. This may or may not cause a problem in actual application use (the symptom is that the non-winning parallel connections are not disconnected properly, and several negotiation timers are left running). Until a fix is developed for either Twisted or PyOpenSSL, the recommended workaround is to downgrade to PyOpenSSL-0.6 . Twisted bug #3218 and Foolscap bug #62 exist to track this problem. ** setup.py is more setuptools-friendly The foolscap version string is located with a regular expression rather than an import, allowing setuptools to install Foolscap as a build-dependency of some other project without having Twisted available first. If setuptools is available, we also declare a dependency upon Twisted (at least 2.4.0), to give more information to the setuptools dependency-auto-installer. ** Unauthenticated FURLs can now contain multiple connection hints Previously they were limited to a single one ** FURLs can now contain extensions, providing forwards-compatibility The parsing of FURLs has been refined to tolerate (and ignore) certain kinds of extensions. The "tubid" section will be able to have additional identifiers (perhaps stronger hashes for the public key, or an encryption-ready EC-DSA public key). In addition, the "connection hints" section will be able to contain alternate protocol specifiers (for TCP over IPv6, or a less connection-oriented UDP transport). By ignoring such extensions, foolscap-0.2.6 will tolerate FURLs produced (with extensions) by some future version of foolscap. This marks the beginning of a "transition period": when such extensions are introduced, 0.2.6 will be the oldest version still capable of interoperating with the extension-using new version. [View Less]

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[Twisted-Python] Cascading services (passing events through connected services)
by Matthieu Brucher May 7, 2008

May 7, 2008

Hi, I'm currently trying to implement the JXTA standard (http://www.jxta.org) in Python using twisted (because it seems to be the right choice). I've implemented the basic parts that are not network related, that is, not much ;) To make a correct JXTA peer (well designed to be modular and to be able to add services), I have cascade several services (I think they should be services, but I can be wrong, I'm a real beginner with Twisted). For instance: network -> TCP transport layer service -… [View More]

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Re: [Twisted-Python] socket error 22
by glyph＠divmod.com May 6, 2008

May 6, 2008

On 02:43 pm, wthie(a)thiengineering.ch wrote: >Hi all Hi Werner! Thanks for reporting this issue. It's always nice to hear about problems under high load. I hope we can get it fixed. >Running on twisted 2.5 OpenBSD I see the following traceback in the >logs every twenty minutes with up to 200 athena/LivePages connected: > return address.IPv4Address('TCP', *(self.socket.getsockname() + >('INET',))) > File "<string>", line 1, in getsockname > > … [View More]

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[Twisted-Python]The problem afer reactor stoped....
by 李祥曦 May 6, 2008

May 6, 2008

Hi,all I want to write a program that can send some e-mails automaticlly,i use the code like this: def sendmail(authenticationUsername, authenticationSecret,fromAddress, toAddress,messageFile,smtpHost, smtpPort=25): resultDeferred = Deferred() senderFactory = ESMTPSenderFactory(authenticationUsername,authenticationSecret,fromAddress,toAddress,messageFile,resultDeferred,requireTransportSecurity=False) reactor.connectTCP(smtpHost, smtpPort, senderFactory) return resultDeferred … [View More]

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Re: [Twisted-Python] Counting errors in a DeferredList and avoiding Unhandled error in Deferred messages
by Terry Jones May 5, 2008

May 5, 2008

Hi Tristan > You might want to look at the gatherResults() utility function which > returns a deferred that either fires with a list of the results, or > errbacks with the first error to occur. Thanks. I can see how I'd write this, given Jean-Paul's reply. Terry

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[Twisted-Python] EuroPython 2008
by Andrew Francis May 5, 2008

May 5, 2008

Hi Folks: I noticed the deadline for EuroPython is May 22nd, 2008. I have been designing a new talk on Stackless and Twisted and I am thinking about submitting a talk proposal. I am curious if anyone is planning to give a talk? Cheers, Andrew ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

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[Twisted-Python] Counting errors in a DeferredList and avoiding Unhandled error in Deferred messages
by Terry Jones May 5, 2008

May 5, 2008

If I pass a list of deferreds to DeferredList and want to add a callback to the DeferredList to look at whatever errors have occurred in the underlying deferreds, should I do something like this: deferreds = [] for x in whatever: deferreds.append(funcReturningDeferred(x)) dl = DeferredList(deferreds) dl.addCallback(errorCheckingFunc) for d in deferreds: d.addErrback(lambda _: pass) This ensures that errorCheckingFunc gets defer.FAILURE for those deferreds that finished up … [View More]

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Re: [Twisted-Python] Problem Changing Time Format of a Log
by Andrew Francis May 5, 2008

May 5, 2008

Hi Zookoo and Cameron: On May 2, 2008, at 9:54 AM, Andrew Francis wrote: >Does this mean that the the method raised an exception >but the twisted logging infrastructure isn't telling >you what the exception was? >I've done this successfully: >http://allmydata.org/trac/tahoe/browser/src/allmydata/node.py? >rev=2360#L201 Thanks for the pointer. A part of my problem was that I forgot to import datetime. Anyhow, I re-read the documentation and solved my problem by doing: … [View More]

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[Twisted-Python] How to get port when using application
by Gabriel Rossetti May 5, 2008

May 5, 2008

Hello, I am going to use application and I have a question, I have a server that needs to get a free port, before I would do this : ... port = reactor.listenTCP(0, f).getHost().port ... and now with application all I could find to do the equivilent was : ... t = internet.TCPServer(0, tcpFactory) port = p._getPort()._realPortNumber ... the problem is that this isn't very clean as I'm accessing protected members. Is there a better way of doing this? Thank you, Gabriel

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[Twisted-Python] DNSQueryRefusedError question
by Alvin Delagon May 5, 2008

May 5, 2008

Can anyone explain what is causing this exception? twisted.names.error.DNSQueryRefusedError: <twisted.names.dns.Message instance at 0xb78470cc> I'm using twisted.mail.smtp which subclasses twisted.names.dns. I keep getting this failure during smtp.sendmail(). Thank you in advance. :) --- Alvin Delagon -- http://www.alvinatorsplayground.blogspot.com/

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[Twisted-Python] Weekly Bug Summary
by exarkun＠twistedmatrix.com May 4, 2008

May 4, 2008

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[Twisted-Python] ldaptor's LDAPClient.send_multiResponse not dealing with chained deferreds, patch
by Michael Torrie May 4, 2008

May 4, 2008

This message is probably for Tv. I have a situation where the callback to a LDAPClient.send_multiResponse() call needs to do a bunch of work that I want to split up over several functions, using deferred chaining. What I want to do is something like this (this in conjunction with an LDAP proxy server I am writing using Twisted and ldaptor): d = self.client.send_multiResponse(request, got_response) then later: def got_response(response): # get a list of other things to do with the … [View More]

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[Twisted-Python] Problem Changing Time Format of a Log
by Andrew Francis May 2, 2008

May 2, 2008

Hi Folks: I need to change date format of a log - the application I am using wants HH:MM:SS. Twisted seems to give back HH:MM. Based on the example in Abe Fettig's book and looking at Twisted.Python.Log (and I am not sure where to define the timeFormat string), I do the following. class MyLog(log.FileLogObserver): def formatTime(self, when): if self.timeFormat is not None: return time.strftime(self.timeFormat, time.localtime(when)) tzOffset = -self.… [View More]

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[Twisted-Python] From asyncore to twisted
by Daniel Brandt May 2, 2008

May 2, 2008

Hello, I'm looking for some advice on how to get started with an asyncore -> Twisted conversion. Being new to twisted I have some trouble getting started (re)designing my system. All ideas are welcome since I'm also doing this to learn. I am about to convert a message-passing daemon written with asyncore to Twisted, and I have two goals in mind. Code that is easier to maintain and expand, and higher reliability. The last part would probably be achievable while sticking with the present … [View More]

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[Twisted-Python] Implement a client to telnet to a Linux machine
by Steven Song May 1, 2008

May 1, 2008

I am new to both Python and Twisted framework, so if this has already been dicussed bofore please excuse me. I am trying to implement a client software using Python to telnet to a Linux machine. The login involves authntication with username and password. Can someone please point me to an example if there is one? I know it has something to do with twisted.conch.telnet but am not sure about the detailed implementation yet. Thanks in advance. … [View More]

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