lxml + mod_python: cannot unmarshal code objects in restricted execution mode

[Graham Dumpleton]

On Sep 13, 11:05 pm, Dmitri Fedoruk <dfedo... at gmail.com> wrote:
> Hello everyone,
>
> I'm developing a mod_python application that is based on XML\XSLT
> transforming.
>
> I used 4Suite libraries for that, but as the speed was unacceptable
> for me, I switched to lxml. Everything became much easier and 10 times
> faster, but I've encountered the subject problem.
>
> In brief - all my data and xslt are stored and transferred in UTF-8.
> With 4Suite everything was fine all the time. With lxml it works fine
> from the console, but inside mod_python it occasionaly dies, ~ one
> time out of three. Strange - the same code with the same data works or
> dies by its own means.
>
> As far as I have found, there was a similar problem with PyXML and
> encodings module, but there was no clear solution.
>
> So, my configuration is the following:
> Python 2.5.1
> Server version: Apache/2.2.4 (FreeBSD)
> mod_python-3.3.1
>
> And the relevant parts of my code are these:
>
> def extApplyXslt(xslt, data, logger ):
>     try:
>         strXslt = urllib2.urlopen(xslt).read()
>         # i have to read the xslt url to the python string
>     except urllib2.HTTPError, e:
>        .......
>     except urllib2.URLError, e:
>        .............
>     try:
>         xslt_parser = etree.XMLParser()
>         xslt_parser.resolvers.add( PrefixResolver("XSLT") )
>
>         # and now I have to use the string; a more elegant solution,
> anyone?
>         f = StringIO(strXslt)
>         xslt_doc = etree.parse(f, xslt_parser)
>
>         # and here where the problem comes
>         transform = etree.XSLT(xslt_doc)
>
>     except Exception, exc:
>         logger.log(logging.CRITICAL, exc.__str__() )
>
>     try:
>       result_tree = transform(data)
>       return etree.tostring(result_tree, 'utf-8')
>     except Exception, exc:
>       print "xslt processing error!", exc.__str__()
>       return ""
>
> It dies with the message 'cannot unmarshal code objects in restricted
> execution mode'. By profiling I detected the point where problem
> occurs:
>  transform = etree.XSLT(xslt_doc)
>
> So, I would be grateful for any suggestions how to get rid of this.
> I'd really like to use lxml. Maybe I should initialize the xslt
> processor in somehow other way?
>
> Thanks in advance,
> Dmitri

Try forcing mod_python to run your code in the first interpreter
instance created by Python.

  PythonInterpreter main_interpreter

If that still doesn't work then you are hitting problems in mod_python
related to how it does GIL management or how the third party package
is implemented and whether it is compatible with use in secondary
Python interpreters. For details see:

If it still doesn't work and your application is a WSGI application
and you aren't using mod_python specific features, only choice at this
point would be to use mod_fastcgi or mod_wsgi instead. If using
mod_wsgi, you would still need to tell it to run your code in first
interpreter instance created by Python.

  WSGIApplicationGroup %{GLOBAL}

For some details on issues related to this problem, see sections
'Python Simplified GIL State API' and 'Multiple Python Sub
Interpreters' in mod_wsgi document:

  http://code.google.com/p/modwsgi/wiki/ApplicationIssues

Graham