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Graham Dumpleton
graham.dumpleton at gmail.com
Wed Aug 6 19:27:13 EDT 2008
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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