How do I set up a local python library directory / PYTHONPATH?

Question

In the process of trying to write a Python script that uses PIL today, I discovered I don't seem have it on my local machine (OS X 10.5.8, default 2.5 Python install).

So I run:

easy_install --prefix=/usr/local/python/ pil

and it complains a little about /usr/local/python/lib/python2.5/site-packages not yet existing, so I create it, and try again, and get this:

TEST FAILED: /usr/local/python//lib/python2.5/site-packages does NOT support .pth files error: bad install directory or PYTHONPATH

You are attempting to install a package to a directory that is not on PYTHONPATH and which Python does not read ".pth" files from. The installation directory you specified (via --install-dir, --prefix, or the distutils default setting) was:

/usr/local/python//lib/python2.5/site-packages

and your PYTHONPATH environment variable currently contains:

''

OK, fair enough -- I hadn't done anything to set the path. So I add a quick line to ~/.bash_profile:

PYTHONPATH="$PYTHONPATH:/usr/local/python/lib/python2.5"

and source it, and try again.

Same error message.

This is kindof curious, given that PYTHONPATH is clearly set; I can echo $PYTHONPATH and get back :/usr/local/python/lib/python2.5. I decided to check out what the include path looked like from inside:

import sys
print "\n".join(sys.path)

which yields:

/System/Library/Frameworks/Python.framework/Versions/2.5/lib/python25.zip /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5 /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/plat-darwin /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/plat-mac /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/plat-mac/lib-scriptpackages /System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/lib-tk /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/lib-dynload /Library/Python/2.5/site-packages /System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/PyObjC

from which /usr/local/python/yadda/yadda is notably missing.

Not sure what I'm supposed to do here. How do I get python to recognize this location as an include path?

UPDATE

As Sven Marnach suggested, I was neglecting to export PYTHONPATH. I've corrected that problem, and now see it show up when I print out sys.path from within Python. However, I still got the TEST FAILED error message I mentioned above, just with my new PYTHONPATH environment variable.

So, I tried changing it from /usr/local/python/lib/python2.5 to /usr/local/python/lib/python2.5/site-packages, exporting, and running the same easy_install command again. This leads to an all new result that at first looked like success (but isn't):

Creating /usr/local/python/lib/python2.5/site-packages/site.py
Searching for pil
Reading http://pypi.python.org/simple/pil/
Reading http://www.pythonware.com/products/pil
Reading http://effbot.org/zone/pil-changes-115.htm
Reading http://effbot.org/downloads/#Imaging
Best match: PIL 1.1.7
Downloading http://effbot.org/media/downloads/PIL-1.1.7.tar.gz
Processing PIL-1.1.7.tar.gz
Running PIL-1.1.7/setup.py -q bdist_egg --dist-dir /var/folders/XW/XWpClVq7EpSB37BV3zTo+++++TI/-Tmp-/easy_install-krj9oR/PIL-1.1.7/egg-dist-tmp--Pyauy
--- using frameworks at /System/Library/Frameworks
[snipped: compiler warnings]
--------------------------------------------------------------------
PIL 1.1.7 SETUP SUMMARY
--------------------------------------------------------------------
version       1.1.7
platform      darwin 2.5.1 (r251:54863, Sep  1 2010, 22:03:14)
              [GCC 4.0.1 (Apple Inc. build 5465)]
--------------------------------------------------------------------
--- TKINTER support available
--- JPEG support available
--- ZLIB (PNG/ZIP) support available
*** FREETYPE2 support not available
*** LITTLECMS support not available
--------------------------------------------------------------------
To add a missing option, make sure you have the required
library, and set the corresponding ROOT variable in the
setup.py script.

To check the build, run the selftest.py script.
zip_safe flag not set; analyzing archive contents...
Image: module references __file__
No eggs found in /var/folders/XW/XWpClVq7EpSB37BV3zTo+++++TI/-Tmp-/easy_install-krj9oR/PIL-1.1.7/egg-dist-tmp--Pyauy (setup script problem?)

Again, this looks good, but when I go to run my script:

Traceback (most recent call last):
File "checkerboard.py", line 1, in import Image, ImageDraw ImportError: No module named Image

When I check what's now under /usr/local/python/ using find ., I get:

./lib ./lib/python2.5 ./lib/python2.5/site-packages ./lib/python2.5/site-packages/site.py ./lib/python2.5/site-packages/site.pyc

So... nothing module-looking (I'm assuming site.py and site.pyc are metadata or helper scripts). Where did the install go?

I note this:

To check the build, run the selftest.py script.

But don't really know what that is.

And I also noticed the "No eggs found" message. Are either of these hints?

Answer 1

You are using the Apple-supplied Python 2.5 in OS X; it's a framework build and, by default, uses /Library/Python/2.5/site-packages as the location for installed packages, not /usr/local. Normally you shouldn't need to specify --prefix with an OS X framework build. Also beware that the setuptools (easy_install) supplied by Apple with OS X 10.5 is also rather old as is the version of Python itself.

That said, installing PIL completely and correctly on OS X especially OS X 10.5 is not particularly simple. Search the archives or elsewhere for tips and/or binary packages. Particularly if you are planning to use other modules like MySQL or Django, my recommendation is to install everything (Python and PIL) using a package manager like MacPorts.

Answer 2

Why did you specify --prefix in your easy_install invocation? Did you try just:

sudo easy_install pil

If you're only trying to install PIL to the default location, I would think easy_install could work out the correct path. (Clearly, /usr/local/python isn't it...)

EDIT: Someone down-voted this answer, maybe because it was too terse . That's what I get for trying to post an answer from my cell phone, I guess. But the gist of it is perfectly valid, IMHO: if you're using --prefix to specify a custom install location with easy_install, you're kind of 'doing it wrong'. It might be possible to make this work, but the easy_install documentation has a section on custom installation locations that doesn't even mention this as a possibility, except as a small tweak to the virtual python option. I'd suggest following the OS X instructions if you want to install to a custom location on a Mac, --prefix just does not seem like the right tool for the job.