Manel! I think you've solved it.
With your extra push I found: http://codespeak.net/lxml/FAQ.html#my-program-crashes-when-run-with-mod-python-pyro-zope-plone And then re-built lxml like: sudo python26 setup.py --without-threading install And things now work without the: > WSGIApplicationGroup %{GLOBAL} Nice! Daniel, can you try that? FYI, wrapping the mapnik::load_map call in 'Py_BEGIN_ALLOW_THREADS' had no positive effect, although this is what we do for the render call: http://trac.mapnik.org/browser/trunk/bindings/python/mapnik_python.cpp#L83 Dane On Oct 6, 2010, at 3:07 AM, <[email protected]> <[email protected]> wrote: > Hi, > > summary of my debugging session: > > - The freeze happens once you install python-lxml, there is no proble mwith > other etree implementations ogcserver imports. > - I can reproduce it with just mod_python + ogcserver + mapnik (0.7 in > ubuntu), no wsgi involved > - It looks the problem is a deadlock involving the GIL. I tried moving the > load_XML call outside the __init__ function, so that it was not under an > import call, but no luck. Some other code must be acquiring the GIL and not > releasing it. I'll try to debug the GIL to find the problem. > > As you can see in the backtrace, lxml etree implementation will call > PyGILState_Ensure, which will cause the thread to sleep, waiting for some > other code to release the GIL => deadlock because that will never happen. > > Here is some inspiration: > http://bugs.python.org/issue7736 > > And some documentation: > http://wiki.python.org/moin/boost.python/HowTo > > > (gdb) backtrace > #0 0xb773b430 in __kernel_vsyscall () > #1 0xb769b245 in sem_wait@@GLIBC_2.1 () from > /lib/tls/i686/cmov/libpthread.so.0 > #2 0xb65fce10 in PyThread_acquire_lock (lock=0xb80f1568, waitflag=1) at > ../Python/thread_pthread.h:349 > #3 0xb65cc798 in PyEval_RestoreThread (tstate=0xb809b9a0) at > ../Python/ceval.c:353 > #4 0xb65efa90 in PyGILState_Ensure () at ../Python/pystate.c:592 > #5 0xb237465e in __pyx_f_4lxml_5etree__local_resolver > (__pyx_v_c_url=0xb855194c "/home/manel/ogcserver/world.xml", > __pyx_v_c_pubid=0x0, __pyx_v_c_context=0xb855b4c8) at > src/lxml/lxml.etree.c:62627 > #6 0xb6931343 in xmlLoadExternalEntity () from /usr/lib/libxml2.so.2 > #7 0xb6920891 in xmlCtxtReadFile () from /usr/lib/libxml2.so.2 > #8 0xb53cbc64 in mapnik::libxml2_loader::load(std::string > const&,boost::property_tree::basic_ptree<boost::property_tree::ptree_traits<char> > >&) () from /usr/lib/libmapnik.so.0.7 > #9 0xb53ca537 in mapnik::read_xml2(std::string const&, > boost::property_tree::basic_ptree<boost::property_tree::ptree_traits<char> > >&) () from /usr/lib/libmapnik.so.0.7 > #10 0xb538a7e4 in mapnik::load_map(mapnik::Map&, std::string const&, bool) () > from /usr/lib/libmapnik.so.0.7 > #11 0xb55bd83c in > load_map_overloads::non_void_return_type::gen<boost::mpl::vector4<void, > mapnik::Map&, std::string const&, bool> >::func_1(mapnik::Map&, std::string > const&, bool) () from /usr/lib/pymodules/python2.6/mapnik/_mapnik.so > ... > > -- > Manel > > ________________________________ > > De: [email protected] > [mailto:[email protected]] En nombre de Dane Springmeyer > Enviado el: sábado, 02 de octubre de 2010 0:13 > Para: [email protected] > CC: [email protected] > Asunto: Re: [Mapnik-users] Problem with Mapniks OGCServer > > > Okay, I think I found it. > > Putting this in your WSGI config should fix it: > > WSGIApplicationGroup %{GLOBAL} > > More details here: > > > https://techknowhow.library.emory.edu/blogs/branker/2010/07/30/django-lxml-wsgi-and-python-sub-interpreter-magic > > So, this should allow the ogcserver to play nicely within mod_wsgi > with lxml installed. If this fixes the hang for you then we can investigate > more. If not, then make sure you are only running one instance of the > ogcserver within Apache. > > Dane > > > On Oct 1, 2010, at 10:59 AM, [email protected] wrote: > > > Hi, I forgot something... > when uninstalling lxml, mod_wsgi can actually connect to > mapniks ogcserver (ogcserver welcome appears). as Dane said earlier in this > thread, mapnik falls back to standard xml support. at least this machine > should... but with a GetMap request the browser still returns no map, the > text of the requested URL gets rendered as an unformatted image instead. > > Daniel > > > Am 30.09.2010 18:14, schrieb Dane Springmeyer: >> >> On Sep 1, 2010, at 3:57 AM,<[email protected]> >> <[email protected]> wrote: >> >>> Hi, >>> >>> Just tried and I can reproduce the same problem here. Ubuntu server 9.10, >>> Mapnik 0.7.1, mod_python will get stuck in Mapnik's load_map in WMS.py. >>> >>> Strange enough, I'm using the *same* code under wsgi with no problems. >>> >> >> Daniel look ^^^. So Manel, what Apache version, prefork or worker, and what >> mod_wsgi and python versions? >> >> Btw, I forgot to mention the ticket we once had that tracked this issue (at >> lease specific to GetCaps): >> >> http://trac.mapnik.org/ticket/464 >> >> It would be good to add any additional info we find to that ticket thread. >> For instance, short of understanding the exact problem within lxml, >> hopefully we can recommend a certain version of python/apache/mod_wsgi which >> will work around the problem. >> >> - Dane > > > > GKSS-Forschungszentrum Geesthacht GmbH > Max-Planck-Straße 1 > 21502 Geesthacht > Deutschland/Germany > > Geschäftsführer/Board of Management: Prof. Dr. Wolfgang A. > Kaysser, Dipl.-Ing. Michael Ganß > Vorsitzender des Aufsichtsrates/Chairman of the Supervisory > Board: Ministerialrat Wilfried Kraus > > Amtsgericht Lübeck HRB 285 GE (Register Court) > Internet: http://www.gkss.de > > ACHTUNG - ATTENTION > > Die GKSS-Forschungszentrum Geesthacht GmbH erhält einen neuen > Namen und heißt ab dem 1. November 2010 offiziell > The GKSS-Forschungszentrum Geesthacht GmbH will change its > name and will as of 1st November 2010 be officially called > > Helmholtz-Zentrum Geesthacht > Zentrum für Material- und Küstenforschung GmbH > _______________________________________________ > Mapnik-users mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/mapnik-users > > > _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
