Mailman 3 December 2002 - Twisted

[Twisted-Python] Twisted Python 0.7.0 Prerelease Testing
by Glyph Lefkowitz Aug. 5, 2021

Aug. 5, 2021

hi there, folks: I'd really like to release 0.7.0 but I would like it to be at least a little bit tested before I do so. Could those of you with CVS trees check everything out and see if it performs as advertised? Deeper bugs than that will have to wait for the next release, but I'd at least like to know if it works for someone other than me. Thanks. ______ __ __ _____ _ _ | ____ | \_/ |_____] |_____| |… [View More]

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[Twisted-Python] Documentation Lacks
by Moshe Zadka Jan. 11, 2003

Jan. 11, 2003

Hi. The following things are undocumented -- any volunteers would be welcome: - conch HOWTO - Twisted chat HOWTO (im, words server, writing bots) - Add tkmktap/tktwistd to basics.html - Twisted news HOWTO - Twisted names HOWTO

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[Twisted-Python] Writing Unittests for Twisted Applications
by Bernhard Herzog Jan. 7, 2003

Jan. 7, 2003

Hi all, I've been working on a project using twisted for the last few weeks. In the process I've written quite a few unittests most of which need to run a twisted reactor either directly as reactor.run or via an Application instance's run() method. It's amazing how difficult that is, given that twisted itself has an extensive set of unittests. Running only one test with a main loop is simple but running several tests that need to listen and unlisten the same ports or that have timeouts, etc. … [View More]seems much more difficult than it should be. How difficult would it be to implement at least one of the following features? 1. a way to reset a reactor so that e.g. a new unit test could start with a clean state. It's OK for me if the unittest itself has to take care to do some things automatically such as disconnecting connections or unlistenting. 2. A base class (derived from unittest.TestCase or as a mix-in class) for tests that need to run the main loop. There should perhaps be two of them, one for plain reactor usage and for test with Application instances. Obviously this would require having 1. to a certain extent. However, it's OK if the class knew how to achieve a reset in as far as that is necessary for test cases. For instance, the base class could require that derived classes don't call the reactor directly to listen or to add delayed calls and go through some method instead to e.g. keep track of the ids returned by reactor.callLater. AFAICT neither is currently implemented in twisted. There even seems to be one unit test (test_sister) that's not implemented because of this. I have effectively implemented no. 2 as part of my unit-tests but only as much as I needed it so far. It didn't take much code but there are some tricky things: 1. After and unlisten when the loop has already been left, call reactor.iterate() to make sure the port is properly freed again. This was relatively easy to figure out because some twisted test cases do this. 2. Application.run() will only run the reactor mainloop if main.running is not true. Unfortunately, main.running is not unset when main.shutdown or main.crash is called, so when trying to enter application main loops more than once, even for different application instances, once has to explicitly unset main.running. My code will eventually be available under GPL as part of the 'GREAT-ER'[1] software we're developing, but it's not yet in CVS. If there's interest in including my test case base class in twisted I could make it available sooner and under LGPL. Bernhard [1] http://great-er.intevation.de/ -- Intevation GmbH http://intevation.de/ Sketch http://sketch.sourceforge.net/ MapIt! http://www.mapit.de/ [View Less]

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[Twisted-Python] POP3 improvements
by Abe Fettig Jan. 2, 2003

Jan. 2, 2003

Over the weekend I was working on adding POP3 support to the messaging library I'm working on. I noticed that while downloading large messages from a POP3 server on my local network my test app would use 100% CPU, and would stop responding to events until it finished downloading the message. Looking at the twisted.protocols.pop3.POP3Client code I saw that it was handling downloaded messages by concatenating a string, adding one line at a time. This seemed like an inefficient way to do it, … [View More]

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[Twisted-Python] DNS SRV support for Connectors
by Tommi Virtanen Jan. 1, 2003

Jan. 1, 2003

Hi. I wanted to have SRV record (RFC 2782) support connecting to services. So here we go. The following patch adds a new Connector class that takes service (smtp, http, ldap, ..) and domain (example.com), looks for a DNS SRV record and falls back sanely if not found. itamar pointed out that this might be more suitable in twisted.names.client -- feel free to point out what is the "right" place. Please give feedback. The patch also fixes the output of SRV-using example; it used to … [View More]

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[Twisted-Python] twisted.protocols.dict update
by Paul Pergamenshchik Dec. 31, 2002

Dec. 31, 2002

Please don't kick me in head. For some reason, Cornell's webmail thingie decided to send the previous e-mail with "twisted-python(a)twistedmatrix.com" in the From: field or something. Or maybe the mailing list is broken. The previous message was from me :)

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[Twisted-Python] twisted.protocols.dict update
by pp64＠cornell.edu Dec. 31, 2002

Dec. 31, 2002

Hi. Could somebody slurp the partially rewritten dict.py and test_dict.py? The URLs are: http://dunce.mine.nu:8080/twidict/Twisted/twisted/protoc ols/dict.py and http://dunce.mine.nu:8080/twidict/Twisted/twisted/test/t est_dict.py Thank you.

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[Twisted-Python] Python and Win32 command execution
by Bram Moolenaar Dec. 31, 2002

Dec. 31, 2002

hello, I noticed your message with an example of using CreateProcess(): http://twistedmatrix.com/pipermail/twisted-python/2002-March/000882.html I actually only need a version of the os.system() command that does return the exit value. The problem is that under Windows 95 and 98 the return value if always zero, thus I don't know if the command actually worked. For my work on A-A-P (http://www.a-a-p.org) I do need to get the exit value. The key to solving the problem apparently is to … [View More]

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[Twisted-Python] t.p.usage suggestion: '--option='
by Tommi Virtanen Dec. 31, 2002

Dec. 31, 2002

As it is now, twisted.python.usage will not allow parameters to have empty strings as values. That is, these are invalid currently: --foo= --foo='' (the same thing, more explicitly) --foo '' I think t.p.usage should not be dictating such policy for its users. It seems this only concerns optParameters users, "def opt_foo(self, x)" seems to be immune to this problem if I'm reading the code correctly. All the above cases are easily detectable, Here's a suggested patch; tell me … [View More]

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[Twisted-Python] intermittent test failures: fixed
by Brian Warner Dec. 31, 2002

Dec. 31, 2002

Hi all.. I spent some time yesterday looking into the intermittent test failures in test_tcp and test_threadpool. These failures only occurred when the full test suite was run (./admin/runtests -v -t), not when test_tcp was run by itself (./admin/runtests -v -t twisted.test.test_tcp). I finally figured out what was happening and wanted to share my findings to help others track down future problems. Early in the test sequence, test_woven did some kind of session/login thing. One particular … [View More]test case was verifying an Unauthorized response, which involved creating a Deferred that was then .errback()'ed. However, there was no errback handler added to the Deferred. Inside that test, web.guard started a 60 second session timeout, with a callLater() function that referenced that Deferred (or an object holding it). test_woven finishes. The timer is still running. The Deferred (with pending error) is still alive, since the callLater timer prevents it from being garbage-collected. Other test cases run. [60 seconds pass] Some other innocent test case is running, depending upon the speed of the machine. On my CPU, it was usually test_tcp. During some call to reactor.iterate, the web.guard session timer expires, the callback does whatever callbacky things it likes, and an object gets freed. That leads to the Deferred being freed. The Deferred has a pending error but no .errback handler. Deferred.__del__ does log.msg() with the "Unhandled error in Deferred" message, and log.err() with the "Unauthorized" Failure object that wanted an .errback but had none. log.err() puts the message in the error queue. log.msg() goes into the test.log file, but not into the error queue. test_tcp finishes without problem, but unittest.py looks in the error queue and sees the Failure. It adds the traceback of the Failure (which is the call trace leading up to the creation of the Unauthorized exception, which is in web.guard, and doesn't mention test_woven at all) to the error results of the test. test_tcp is flunked, and as explanation unittest.py emits the error results (the Unauthorized exception and the web.guard stack trace) The basic issue is timers that "leak" over from one unit test to another. Unit tests are supposed to be isolated from each other, but if one test changes the state of the reactor (by adding timers or establishing listenTCP ports) without cleaning it up when it finishes, that state can affect other tests. This is not always obvious, as several modules create timers internally. This is very convenient, and works fine in normal applications. It is only in the unit tests where it causes a problem. I've added IReactorTime.getDelayedCalls() as a reactor-portable way to retrieve the list of pending callLater() timers, and changed unittest.py to cancel all pending timers between test cases. This succeeded in moving the failure back to the test that caused it. I've also added a warning message (which goes into test.log) that indicates when a test leaves timers running after it completes. There are a handful that do; most are benign but should probably be cleaned up. This warning message may turn into a test failure someday. Some tools I used to track this down, in case they prove useful to others: added code to Deferred and DelayedCall to record the stack track when they are created, then print them in __repr__ or added to the "unhandled error in deferred" Failure. The traceback of creation is often more useful than the traceback of .callback, .errback, or timer execution. added .extra attribute to Failures, insert its contents in the traceback. I used this to display the Deferred-creation traceback. There are still a few issues: I need to implement getDelayedCalls for the cReactor, and my unit test for getDelayedCalls is stymied by a recurring timer created when the 'popsicle' module is imported, but in general it seems to make the unit test suite behave sensibly (no more intermittent failures). cheers, -Brian [View Less]

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