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Graham Dumpleton
graham.dumpleton at gmail.com
Wed Aug 6 19:28:21 EDT 2008
Sorry, that should have been: http://issues.apache.org/jira/browse/MODPYTHON Graham 2008/8/7 Graham Dumpleton <graham.dumpleton at gmail.com>: > 2008/8/7 Jason Carver <ynj0qeh02 at sneakemail.com>: >> Great, thanks for your help! Is there a good place for me to file a feature >> request to have mod_python do something besides crash in this case? > > The problem has been discussed before, but can't see that there is an > issue for it. Issues can be created at: > > http://issues.apache.org/jira/browse/MODPYTHON-202 > > Yes Python could protect against this so a crash doesn't occur, but > your code shouldn't have been doing that in the first place. > > Graham > >> For reference, I have code here to demonstrate the bug and workaround: >> >> def testCrash(req): >> """ >> Reliably crash server (on 2nd page access) >> Open as: http://server/index.py/testCrash >> """ >> handler = logging.StreamHandler(req) >> logging.getLogger('').addHandler( handler ) >> logging.exception('I crash') >> >> #removing this line will cause an apache crash on the >> # second web page access >> logging.getLogger('').removeHandler(handler) >> >> I have confirmed that the workaround works reliably for me. >> >> Cheers, >> Jason >> >> On Tue, Aug 5, 2008 at 8:36 PM, Graham Dumpleton >> graham.dumpleton-at-gmail.com |public mailing list| >> <a9ghk53mp50t at sneakemail.com> wrote: >>> >>> Just realised what the problem is, rather obvious really. >>> >>> You are supplying a mod_python request object 'req' to: >>> >>> logging.getLogger('').addHandler(logging.StreamHandler(req)) >>> >>> You can't do that, as the logging handler you are creating will >>> persist beyond the lifetime of the internals of the 'req' object. >>> Thus, when logging tries to access it later, it will crash Apache. >>> >>> In other words, 'req' is just a wrapper for some internal Apache data >>> structures which will go away. The mod_python code doesn't currently >>> try and protect itself from user code making the mistake of retaining >>> the 'req' object longer than it should and then accessing those >>> internals. >>> >>> Graham >>> >>> 2008/8/6 Jason Carver <ynj0qeh02 at sneakemail.com>: >>> > If I try to install mod_python without python 2.5 installed, mod_python >>> > refuses, so I assume you mean uninstall all versions of python, then >>> > install >>> > python 2.5.2, then mod_python-3.3.1.win32-py2.5-Apache2.2.exe >>> > >>> > I did that, with no changes. I get the same Traceback during mod_python >>> > install and I can still reproduce the crash reliably. >>> > >>> > Bug requirements update: It does not matter if I test the req object, it >>> > only matters if the req object has something set. So these are the new >>> > requirements to reproduce the bug >>> > >>> > use built in logging module >>> > raise Exception >>> > call page with variables (ie~ http://localhost/index.py?action=boom) >>> > use the following code: >>> > >>> > import logging >>> > >>> > def index(req): >>> > """Handles all Browser Requests""" >>> > try: >>> > logging.getLogger('').addHandler( logging.StreamHandler(req) ) >>> > >>> > raise Exception('Goodbye Apache') >>> > >>> > except Exception, e: >>> > logging.exception('I crash') >>> > raise >>> > >>> > So there seems to be some kind of three way interaction between the >>> > logging >>> > module, the apache req module, and exception handling. If any one of >>> > the >>> > three are not involved, apache does not crash... >>> > >>> > For now I can use a home-grown logger to get around the bug, but I hate >>> > to >>> > build code that already exists and make future developers have to learn >>> > my >>> > logger instead of the built-in one. >>> > >>> > Cheers, >>> > Jason >>> > >>> > On Mon, Aug 4, 2008 at 9:44 PM, Graham Dumpleton >>> > graham.dumpleton-at-gmail.com |public mailing list| >>> > <a9ghk53mp50t at sneakemail.com> wrote: >>> >> >>> >> Please use reply-all and keep discussion on the list, don't reply just >>> >> to >>> >> me. >>> >> >>> >> Have you tried uninstalling all versions of Python and mod_python >>> >> first and then install it? Ie., don't install when you have existing >>> >> versions on the system. >>> >> >>> >> When installing packages, are you doing it as a user with >>> >> administrator privileges? >>> >> >>> >> Graham >>> >> >>> >> 2008/8/5 <ynj0qeh02 at sneakemail.com>: >>> >> > Unfortunately, when I tried to install the mod_python 3.3.1 for 2.5 I >>> >> > got >>> >> > this traceback: >>> >> > Traceback (most recent call last): >>> >> > File "boot_com_servers.py", line 21, in <module> >>> >> > File "C:\Python25\Lib\site-packages\pythoncom.py", line 3, in >>> >> > <module> >>> >> > pywintypes.__import_pywin32_system_module__("pythoncom", >>> >> > globals()) >>> >> > File "C:\Python25\Lib\site-packages\win32\Lib\pywintypes.py", line >>> >> > 98, >>> >> > in >>> >> > __import_pywin32_system_module__ >>> >> > ('.dll', 'rb', imp.C_EXTENSION)) >>> >> > ImportError: DLL load failed: The specified procedure could not be >>> >> > found. >>> >> > >>> >> > and when I try to start apache 2 anyway, it says "The requested >>> >> > operation >>> >> > has failed!" >>> >> > >>> >> > That's why I was using the version for 2.4. >>> >> > >>> >> > On Mon, Aug 4, 2008 at 9:21 PM, Graham Dumpleton >>> >> > graham.dumpleton-at-......... |public mailing list| <...> wrote: >>> >> >> >>> >> >> 2008/8/5 <ynj0qeh02 at sneakemail.com>: >>> >> >> > Thanks for the quick reply! Answers inline... >>> >> >> > >>> >> >> > On Mon, Aug 4, 2008 at 7:28 PM, Graham Dumpleton >>> >> >> > graham.dumpleton-at-......... |public mailing list| <...> wrote: >>> >> >> >> >>> >> >> >> What operating system? What version of Python? What version of >>> >> >> >> mod_python? >>> >> >> > >>> >> >> > I am on Windows XP SP3 using Python 2.5 in mod_python 3.3.1 >>> >> >> > >>> >> >> > I hacked the binary to use 2.5 on Windows, but the same problem is >>> >> >> > reproducible on Ubuntu 7.10 using the latest source from svn >>> >> >> > compiled >>> >> >> > with >>> >> >> > python 2.5. >>> >> >> > >>> >> >> >> What startup messages for mod_python are in the Apache error log? >>> >> >> > >>> >> >> > >>> >> >> > [Mon Aug 04 20:03:21 2008] [notice] Server built: Nov 7 2007 >>> >> >> > 11:48:48 >>> >> >> > [Mon Aug 04 20:03:21 2008] [notice] Parent: Created child process >>> >> >> > 27164 >>> >> >> > [Mon Aug 04 20:03:22 2008] [error] python_init: Python version >>> >> >> > mismatch, >>> >> >> > expected '2.4.3', found '2.5'. >>> >> >> >>> >> >> This is why it is probably breaking. Install mod_python compiled >>> >> >> against Python 2.5. The version you are using was compiled against >>> >> >> older version of Python. >>> >> >> >>> >> >> Fix your installation and try again. >>> >> >> >>> >> >> Do you get similar warnings on your other platform as well? >>> >> >> >>> >> >> Graham >>> >> >> >>> >> >> > [Mon Aug 04 20:03:22 2008] [error] python_init: Python executable >>> >> >> > found >>> >> >> > 'C:\\xampp\\apache\\bin\\apache.exe'. >>> >> >> > [Mon Aug 04 20:03:22 2008] [error] python_init: Python path being >>> >> >> > used >>> >> >> > 'C:\\Program >>> >> >> > >>> >> >> > >>> >> >> > >>> >> >> > Files\\OpenLibraries\\python;C:\\WINDOWS\\system32\\python25.zip;C:\\Python25\\Lib;C:\\Python25\\DLLs;C:\\Python25\\Lib\\lib-tk;;C:\\xampp\\apache\\bin'. >>> >> >> > [Mon Aug 04 20:03:22 2008] [notice] mod_python: Creating 8 session >>> >> >> > mutexes >>> >> >> > based on 0 max processes and 250 max threads. >>> >> >> > >>> >> >> >> >>> >> >> >> >>> >> >> >> What is the mod_python configuration you have in Apache >>> >> >> >> configuration >>> >> >> >> files? >>> >> >> > >>> >> >> > >>> >> >> > PythonOption mod_python.mutex_directory "/pytmp" >>> >> >> > PythonOption mod_python.mutex_locks 8 >>> >> >> > >>> >> >> > AliasMatch ^/slique(.*) 'C:/Documents and >>> >> >> > Settings/Jason/My >>> >> >> > Documents/Coding/eclipse-workspace/slique-dev/src/$1' >>> >> >> > >>> >> >> > <Directory 'C:/Documents and Settings/Jason/My >>> >> >> > Documents/Coding/eclipse-workspace/slique-dev/src'> >>> >> >> > Options Indexes ExecCGI FollowSymLinks MultiViews >>> >> >> > AllowOverride All >>> >> >> > >>> >> >> > AddHandler mod_python .py >>> >> >> > PythonHandler mod_python.publisher >>> >> >> > PythonDebug On >>> >> >> > PythonPath "sys.path + ['C:/Documents and Settings/Jason/My >>> >> >> > Documents/Coding/eclipse-workspace/slique-dev/src']" >>> >> >> > >>> >> >> > </Directory> >>> >> >> > >>> >> >> >> >>> >> >> >> >>> >> >> >> Specifically, are you setting PythonPath directive in really >>> >> >> >> strange >>> >> >> >> ways? >>> >> >> > >>> >> >> > PythonPath is set this way >>> >> >> > PythonPath "sys.path + ['C:/Documents and Settings/Jason/My >>> >> >> > Documents/Coding/eclipse-workspace/slique-dev/src']" >>> >> >> > >>> >> >> >> >>> >> >> >> >>> >> >> >> Does it happen if you don't use the 'logging' module? >>> >> >> > >>> >> >> > If I comment out logging.exception('I crash'), then the traceback >>> >> >> > prints >>> >> >> > to >>> >> >> > screen as expected. >>> >> >> > >>> >> >> >> >>> >> >> >> Graham >>> >> >> >> >>> >> >> >> 2008/8/5 Jason Carver <ynj0qeh02 at sneakemail.com>: >>> >> >> >> > Here is code that consistently crashes Apache for me: >>> >> >> >> > >>> >> >> >> > import logging >>> >> >> >> > >>> >> >> >> > def index(req): >>> >> >> >> > """Handles all Browser Requests""" >>> >> >> >> > try: >>> >> >> >> > reqHandler = logging.StreamHandler(req) >>> >> >> >> > logging.getLogger('').addHandler(reqHandler) >>> >> >> >> > if req.form.has_key('action'): >>> >> >> >> > raise Exception('Goodbye Apache') >>> >> >> >> > except Exception, e: >>> >> >> >> > logging.exception('I crash') >>> >> >> >> > raise >>> >> >> >> > >>> >> >> >> > Now just go to the site with /?action=dosomething and it will >>> >> >> >> > crash >>> >> >> >> > >>> >> >> >> > Removing the if statement, the exception, or the logger are all >>> >> >> >> > ways >>> >> >> >> > of >>> >> >> >> > alleviating the crash, but none of them should be necessary. >>> >> >> >> > >>> >> >> >> > Cheers, >>> >> >> >> > Jason >>> >> >> >> > >>> >> >> >> > On Mon, Aug 4, 2008 at 2:51 PM, Jason Carver >>> >> >> >> > <ynj0qeh02 at sneakemail.com> >>> >> >> >> > wrote: >>> >> >> >> >> >>> >> >> >> >> Hi all, >>> >> >> >> >> >>> >> >> >> >> I am having the craziest error, confirmed on both a LAMPython >>> >> >> >> >> and >>> >> >> >> >> WAMPython setup: exceptions in mod_python are causing Apache >>> >> >> >> >> to >>> >> >> >> >> crash >>> >> >> >> >> hard. >>> >> >> >> >> Even stranger is that the exceptions have to meet a few >>> >> >> >> >> specific >>> >> >> >> >> conditions >>> >> >> >> >> to cause Apache to crash. >>> >> >> >> >> >>> >> >> >> >> As best I can tell those conditions include: >>> >> >> >> >> >>> >> >> >> >> raising an exception (this problem always goes away if the >>> >> >> >> >> exception >>> >> >> >> >> is >>> >> >> >> >> commented out) >>> >> >> >> >> having the exception be inside an if-block that tests a >>> >> >> >> >> dictionary >>> >> >> >> >> (the >>> >> >> >> >> problem goes away if I do something like """if 'hello' == >>> >> >> >> >> 'hello': >>> >> >> >> >> raise >>> >> >> >> >> Exception('goodbye')""") >>> >> >> >> >> catching the exception and logging it using the python >>> >> >> >> >> built-in >>> >> >> >> >> logging.exception(e) (the problem goes away if I comment out >>> >> >> >> >> the >>> >> >> >> >> logger) >>> >> >> >> >> >>> >> >> >> >> Apache does not write anything to its error.log, so it was a >>> >> >> >> >> bit >>> >> >> >> >> of >>> >> >> >> >> an >>> >> >> >> >> adventure to discover all these elements. >>> >> >> >> >> >>> >> >> >> >> Any ideas? >>> >> >> >> >> >>> >> >> >> >> Cheers, >>> >> >> >> >> Jason >>> >> >> >> > >>> >> >> >> > _______________________________________________ >>> >> >> >> > Mod_python mailing list >>> >> >> >> > Mod_python at modpython.org >>> >> >> >> > http://mailman.modpython.org/mailman/listinfo/mod_python >>> >> >> >> > >>> >> >> >> > >>> >> >> > >>> >> >> > >>> >> > >>> >> > >>> > >>> > >>> > _______________________________________________ >>> > Mod_python mailing list >>> > Mod_python at modpython.org >>> > http://mailman.modpython.org/mailman/listinfo/mod_python >>> > >>> > >>> _______________________________________________ >>> Mod_python mailing list >>> Mod_python at modpython.org >>> http://mailman.modpython.org/mailman/listinfo/mod_python >> >> >> _______________________________________________ >> Mod_python mailing list >> Mod_python at modpython.org >> http://mailman.modpython.org/mailman/listinfo/mod_python >> >> >
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