Set LD_LIBRARY_PATH before importing in python

python import environment-variables sys
iFreilicht picture iFreilicht · Apr 23, 2014 · Viewed 71.4k times · Source

Python uses the PYTHONPATH environment-variable to determine in which folders it should look for modules. You can play around with it by modifying sys.path, which works nicely for pure Python-Modules. But when a module uses shared object files or static libraries, it looks for those in LD_LIBRARY_PATH (on linux), but this can't be changed as easily and is platform dependent as far as I know.

The quick-fix for this problem is of course to set the environment-variable or invoke the script like LD_LIBRARY_PATH=. ./script.py, but then you'll have to set it again for every new shell you open. Also, the .so files in my case will always be in the same directory as the .py file, but may very well be moved to another absolute path, so I'd like to set them automatically every time I invoke the script.

How can I edit the path in which the Python interpreter looks for libraries platform-independently on runtime?

EDIT:

I already tried os.environ['LD_LIBRARY_PATH'] = os.getcwd(), but to no avail.

Answer

Erik Kaplun picture Erik Kaplun · Apr 23, 2014

UPDATE: see the EDIT below.

I would use:

import os

os.environ['LD_LIBRARY_PATH'] = os.getcwd()  # or whatever path you want

This sets the LD_LIBRARY_PATH environment variable for the duration/lifetime of the execution of the current process only.

EDIT: it looks like this needs to be set before starting Python: Changing LD_LIBRARY_PATH at runtime for ctypes

So I'd suggest going with a wrapper .sh (or .py if you insist) script. Also, as @chepner pointed out, you might want to consider installing your .so files in a standard location (within the virtualenv).

See also Setting LD_LIBRARY_PATH from inside Python

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