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I am running a linux box with ubuntu 14, it runs an apache2 server that hosts a Django application. This application imports PIL from the installed Pillow library. It was all working fine when I was on Python 3.5, however after upgrading to Python 3.6 and reinstalling Pillow in the Virtualenv, I get an error when the webserver tries importing PIL.

When I run the Python interpreter it all imports fine as it uses the py script directly however as the webserver is using the installed and compiled pillow library it is failing. The error from Django shows the stack as such:

    Internal Server Error: /ticket-printing/
    Traceback (most recent call last):
      File "/home/ubuntu/ipos-venv/lib/python3.6/site-packages/django/core/handlers/exception.py", line 41, in inner
response = get_response(request)
      File "/home/ubuntu/ipos-venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 249, in _legacy_get_response
response = self._get_response(request)
      File "/home/ubuntu/ipos-venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 187, in _get_response
        response = self.process_exception_by_middleware(e, request)
      File "/home/ubuntu/ipos-venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 185, in _get_response
        response = wrapped_callback(request, *callback_args, **callback_kwargs)
      File "/home/ubuntu/ipos/tickets/views.py", line 30, in stic_app
PrintList.initiateSticApp(request)
      File "/home/ubuntu/ipos/tickets/models.py", line 434, in initiateSticApp
BrandLogo.createBlankLogo()
      File "/home/ubuntu/ipos/store_admin/brands/models.py", line 108, in createBlankLogo
from PIL import Image
      File "/home/ubuntu/ipos-venv/lib/python3.6/site-packages/Pillow-4.1.0-py3.6-linux-x86_64.egg/PIL/Image.py", line 56, in <module>
from . import _imaging as core
      File "/home/ubuntu/ipos-venv/lib/python3.6/site-packages/Pillow-4.1.0-py3.6-linux-x86_64.egg/PIL/_imaging.py", line 7, in <module>
__bootstrap__()
      File "/home/ubuntu/ipos-venv/lib/python3.6/site-packages/Pillow-4.1.0-py3.6-linux-x86_64.egg/PIL/_imaging.py", line 6, in __bootstrap__
imp.load_dynamic(__name__,__file__)
    ImportError: /home/ubuntu/ipos-venv/lib/python3.6/site-packages/Pillow-4.1.0-py3.6-linux-x86_64.egg/PIL/_imaging.cpython-36m-x86_64-linux-gnu.so: undefined symbol: PySlice_AdjustIndices

I've tried uninstalling, reinstalling Pillow via pip, easy_install and the tar.gz setup.py method and all fail.

Any guidance and help would be much appreciated.

Thanks

Artisan
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  • What is your version of Pillow? You may encounter compatibility problems installing a specific version using Python 3.6.x: https://pillow.readthedocs.io/en/4.1.x/installation.html#notes I you use virtualenv, I guess you have a specific old Pillow version in your requirements.txt. – Q Caron Apr 27 '17 at 15:21
  • I tried both 4.0.0 and 4.1.0, the former worked fine with Python 3.5 – Artisan Apr 28 '17 at 02:14

1 Answers1

4

Whoa that was a whole bunch of WTH...

Ok so after trying almost every combination of installing and reinstalling Pillow, I decided to take a look at my apache2/mod_wsgi set up.

It turns out that my version of mod_wsgi compiled with Python 2.7 was not capable of running the server while calling the Pillow compiled files.

So after following some of the instructions here: https://pypi.python.org/pypi/mod_wsgi

I used pip install mod_wsgi in my virtualenv which created an .so file in the site-packages/mod_wsgi folder of my virtualenv. I then copied that file over to /usr/lib/apache2/modules/mod_wsgi.so-X.X and then modified the /etc/apache2/mods-enabled/wsgi.load file to point to the new .so-X.X file.

Restarted apache2 and the error ceased to appear again.

One day I'll understand these things... One day...

Artisan
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  • You may be interested in this thread: http://stackoverflow.com/questions/35613336/debian-mod-wsgi-no-module-named-psycopg2-psycopg – Q Caron Apr 28 '17 at 08:03
  • Wow exactly the same scenario, thanks @QCaron for the link and the follow through – Artisan Apr 29 '17 at 08:32