Matplotlib and WSGI/mod_python not working on Apache.

Question

Everything works as supposed to on the Django development server. In Apache, the django app also works except when matplotlib is used. Here's the error I get:

No module named multiarray.

Exception Type: ImportError 
Exception Value: No module named multiarray 
Exception Location: /usr/share/pyshared/numpy/core/numerictypes.py in <module>, line 81 
Python Executable: /usr/bin/python 
Python Version: 2.6.4 

From the python shell, both statements work: import numpy.core.multiarray and import multiarray. Any ideas? Thanks

As I'm looking over the numpy files, I found the multiarray module, which has an extension of 'so'. My guess, is that mod_python is not reading these files.

Answer 1

On Win32 I solved a similar problem (not being able to load pyd modules through ISAPI_WSGI (IIS)) by downgrading from py2.6.5 to py2.5. It seems like this might be a Python bug that has been re-introduced. See for example this discussion.

Answer 2

Problem solved. Here's what I did.

First of all, before I was getting the import error:

"No module named multiarray."

I was getting an error like this:

": Failed to create /some/dir/.matplotlib; consider setting MPLCONFIGDIR to a writable directory for matplotlib configuration data"

By adding the pyshared folder to the PythonPath variable, this error went away and I got the import error.

So here's how I fixed it:

Removed the pyshared folder from the PythonPath variable.

Before importing the matplotlib module, add these lines:

import os
os.environ['HOME']='/some/writable/dir'

Next, before import matplotlib.pyplot or pylab, add these lines:

import matplotlib
matplotlib.use('Agg') 
# 'Agg' or whatever your backend is.

This is documented here.

That's is! It's working on python2.5 for me now. But I believe it'll work on 2.6 as well.