Damian Powązka, 26.12.2011 18:36:

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W dniu 21 grudnia 2011 18:51 użytkownik Stefan Behnel napisał:

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Damian Powązka, 21.12.2011 18:11:

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I don't share objects across threads. Problem occurs when trying to use etree.XMLSchema or etree.XMLParser with schema provided the error that I sometime see is:

   File "xmlschema.pxi", line 105, in lxml.etree.XMLSchema.__init__ (src/lxml/lxml.etree.c:132605) lxml.etree.XMLSchemaParseError: Operation in progress

That's completely unrelated to the FAQ entry you referenced then.

I pasted your error message into a search engine and it turned up a couple of references that hint at HTTP access, or at least an I/O error (that's where the error message comes from: errno == EINPROGRESS). Just a stab in the dark: maybe your XML catalogues are not properly set up? Apart from that, I have no idea what kind of I/O you do, so I can't comment on it.

I have found a temporary work around for the problem: https://techknowhow.library.emory.edu/blogs/branker/2010/07/30/django-lxml-w...

For which of the problems you described is that?

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but in long term limitation to only one WSGI is bit problematic. Any chance that this issue could be fixed?

Potentially, yes. It may or may not get fixed by a change I've been working on for a while, which would basically introduce a per-document lock around tree modifications, thus making it safe to read and modify trees concurrently in different threads. However, I don't know when (or if) that'll get finished.

It would certainly help if you could come up with a short code snippet that shows the problem (and that doesn't depend on mod_wsgi).

Stefan

Hi, Same problematic code run without mod_wsgi executes without issue.

From what I learned the problem occurs when making an instance of etree.XMLSchema on the xsd that contains xsd:import. I have tried using resolvers but it wasn't called when running on mod_wsgi, so the problem must be somewhere before Resolvers are used.

I may try to simulate way how python instance is created by mod_wsgi. For now I could provide you a VirtualBox machine that has everything setup, so I could see the issue for yourself. I am not sure that is has to do something with threading or locking as the problem occurs always - I am not able to make a single successful http call. WSGIApplicationGroup %{GLOBAL} fixes a problem. My guess would be that XMLSchema on xsd:import does something odd with pointer to python interpreter. Best Regards, Damian Powazka