mod_wsgi issue: solved

[David Malcolm]

I've been trying to deploy rpmgrok (a Turbogears 1 app [1]) behind
mod_wsgi, and finally figured out why mod_wsgi stopped working when I
added a WSGIProcessGroup directive (which avoids having to start a new
process per http request)

I know bpeck has had similar issues with his "beaker" code [2]

It was working on publictest14.fp.org, but not on my local workstation
(both RHEL-5 running mod_wsgi from EPEL).

Attempts to browse led to no response coming from httpd, and no log.

It turned out, I had mod_python installed on the box.

Upon disabling "LoadModule python_module modules/mod_python.so"
from /etc/httpd/conf.d/python.conf it worked.

Known issue?  http://code.google.com/p/modwsgi/wiki/InstallationIssues
describes another mod_wsgi/mod_python incompatibility, but the symptoms
seem different [3]


Hope this helps
Dave

[1] https://fedorahosted.org/rpmgrok/
[2] https://fedorahosted.org/beaker/
[3] debugging attempts led me to find "stuck" httpd threads waiting
forever for the global interpreter lock, presumably acquired by
mod_python elsewhere in the process:
(gdb) bt
#0  0x005bf402 in __kernel_vsyscall ()
#1  0x0018331e in sem_wait(a)GLIBC_2.0 ()
from /lib/i686/nosegneg/libpthread.so.0
#2  0x01d97f3b in PyThread_acquire_lock ()
from /usr/lib/libpython2.4.so.1.0
#3  0x01d74d57 in PyEval_RestoreThread ()
from /usr/lib/libpython2.4.so.1.0
#4  0x01d9104f in PyGILState_Ensure () from /usr/lib/libpython2.4.so.1.0
#5  0x00c65785 in wsgi_start_process (p=0x918a550, daemon=0x92b91a8) at
mod_wsgi.c:8706
#6  0x00c661b3 in wsgi_hook_init (pconf=0x918a550, ptemp=0x91b8608,
plog=0x91bc618, s=0x918c3f0) at mod_wsgi.c:8919
#7  0x00c27783 in ap_run_post_config (pconf=0x918a550, plog=0x91b8608,
ptemp=0x91bc618, s=0x918c3f0)
at /usr/src/debug/httpd-2.2.3/server/config.c:91
#8  0x00c1311d in main (argc=152602056, argv=0x9281448)
at /usr/src/debug/httpd-2.2.3/server/main.c:706

and:
 grep /proc/$PID/maps  mod_
showed mod_python to be loaded.

[Toshio Kuratomi]

David Malcolm wrote:
>  I've been trying to deploy rpmgrok (a Turbogears 1 app [1])
> behind
>  mod_wsgi, and finally figured out why mod_wsgi stopped working when I
>  added a WSGIProcessGroup directive (which avoids having to start a new
>  process per http request)
>  
>  I know bpeck has had similar issues with his "beaker" code [2]
>  
>  It was working on publictest14.fp.org, but not on my local workstation
>  (both RHEL-5 running mod_wsgi from EPEL).
>  
>  Attempts to browse led to no response coming from httpd, and no log.
>  
>  It turned out, I had mod_python installed on the box.
>  
>  Upon disabling "LoadModule python_module modules/mod_python.so"
>  from /etc/httpd/conf.d/python.conf it worked.
>  
>  Known issue?  http://code.google.com/p/modwsgi/wiki/InstallationIssues
>  describes another mod_wsgi/mod_python incompatibility, but the symptoms
>  seem different [3]
>   
I know that we had problems with mod_wsgi and mod_python running
together but don't know if it was the same issue.  At this point I
believe we aren't running mod_python anywhere (definitely not on the app
servers in any case).

-Toshio

[Nigel Jones]

Only trac (hosted1/hosted2) if memory serves correct.

- Nigel
----- "Toshio Kuratomi" <a.badger(a)gmail.com&gt; wrote:

>  David Malcolm wrote:
>  > I've been trying to deploy rpmgrok (a Turbogears 1 app [1]) behind
>  > mod_wsgi, and finally figured out why mod_wsgi stopped working when
>  I
>  > added a WSGIProcessGroup directive (which avoids having to start a
>  new
>  > process per http request)
>  > 
>  > I know bpeck has had similar issues with his "beaker" code [2]
>  > 
>  > It was working on publictest14.fp.org, but not on my local
>  workstation
>  > (both RHEL-5 running mod_wsgi from EPEL).
>  > 
>  > Attempts to browse led to no response coming from httpd, and no
>  log.
>  > 
>  > It turned out, I had mod_python installed on the box.
>  > 
>  > Upon disabling "LoadModule python_module modules/mod_python.so"
>  > from /etc/httpd/conf.d/python.conf it worked.
>  > 
>  > Known issue? 
>  http://code.google.com/p/modwsgi/wiki/InstallationIssues
>  > describes another mod_wsgi/mod_python incompatibility, but the
>  symptoms
>  > seem different [3]
>  > 
>  I know that we had problems with mod_wsgi and mod_python running
>  together but don't know if it was the same issue.  At this point I
>  believe we aren't running mod_python anywhere (definitely not on the
>  app
>  servers in any case).
>  
>  -Toshio
>  
>  
>  _______________________________________________
>  Fedora-infrastructure-list mailing list
>  Fedora-infrastructure-list(a)redhat.com
>  https://www.redhat.com/mailman/listinfo/fedora-infrastructure-list

[Toshio Kuratomi]

Nigel Jones wrote:
>  Only trac (hosted1/hosted2) if memory serves correct.
>   
That's been converted too.

-Toshio

>  - Nigel
>  ----- "Toshio Kuratomi" <a.badger(a)gmail.com&gt; wrote:
>  
> > David Malcolm wrote:
> >> I've been trying to deploy rpmgrok (a Turbogears 1 app [1]) behind
> >> mod_wsgi, and finally figured out why mod_wsgi stopped working when
> > I
> >> added a WSGIProcessGroup directive (which avoids having to start a
> > new
> >> process per http request)
> >>
> >> I know bpeck has had similar issues with his "beaker" code [2]
> >>
> >> It was working on publictest14.fp.org, but not on my local
> > workstation
> >> (both RHEL-5 running mod_wsgi from EPEL).
> >>
> >> Attempts to browse led to no response coming from httpd, and no
> > log.
> >> It turned out, I had mod_python installed on the box.
> >>
> >> Upon disabling "LoadModule python_module modules/mod_python.so"
> >> from /etc/httpd/conf.d/python.conf it worked.
> >>
> >> Known issue? 
> > http://code.google.com/p/modwsgi/wiki/InstallationIssues
> >> describes another mod_wsgi/mod_python incompatibility, but the
> > symptoms
> >> seem different [3]
> >>
> > I know that we had problems with mod_wsgi and mod_python running
> > together but don't know if it was the same issue.  At this point I
> > believe we aren't running mod_python anywhere (definitely not on the
> > app
> > servers in any case).
> >
> > -Toshio
> >
> >
> > _______________________________________________
> > Fedora-infrastructure-list mailing list
> > Fedora-infrastructure-list(a)redhat.com
> > https://www.redhat.com/mailman/listinfo/fedora-infrastructure-list
>  
>  _______________________________________________
>  Fedora-infrastructure-list mailing list
>  Fedora-infrastructure-list(a)redhat.com
>  https://www.redhat.com/mailman/listinfo/fedora-infrastructure-list
>