Cannot Load Python Bindings for PostgreSQL - psycopg2

Question

Once upgraded from Lion Mountain to Mavericks (10.9.4), Trac installation stopped working.

First, I try to get it solved by upgrading the Trac installation, but I'm getting the following error message:

$ trac-admin /Users/myuser/Documents/2014/trac upgrade
Error: Cannot load Python bindings for PostgreSQL

Then, by testing directly on the Python console, I can say that this is consistent since I'm getting an equivalent error:

 $ python
 Python 2.7.5 (default, Mar  9 2014, 22:15:05) 
 [GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)] on darwin
 Type "help", "copyright", "credits" or "license" for more information.
 >>> import psycopg2
 Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   File "/Library/Python/2.7/site-packages/psycopg2/__init__.py", line 50, in <module>
     from psycopg2._psycopg import BINARY, NUMBER, STRING, DATETIME, ROWID
 ImportError: dlopen(/Library/Python/2.7/site-packages/psycopg2/_psycopg.so, 2)
 Library not loaded: libssl.1.0.0.dylib
   Referenced from: /Library/Python/2.7/site-packages/psycopg2/_psycopg.so
   Reason: image not found
 >>> 

I have already tried multiple approaches: installing and uninstalling psycopg2 (using pip and easy_install), or even building psycopg2 from sources.

Then, looking around for a solution, I have found some suggestions in these related questions Q1, Q2 and Q3, but without success yet.

otool, is giving me the following output:

$ otool -L /Library/Python/2.7/site-packages/psycopg2/_psycopg.so

/Library/Python/2.7/site-packages/psycopg2/_psycopg.so:
     libpq.5.dylib (compatibility version 5.0.0, current version 5.5.0)
     libssl.1.0.0.dylib (compatibility version 1.0.0, current version 1.0.0)
     libcrypto.1.0.0.dylib (compatibility version 1.0.0, current version 1.0.0)
     /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.1.1)

Then, I have tried by setting the DYLD_FALLBACK_LIBRARY_PATH environment variable like this:

 $ echo $DYLD_FALLBACK_LIBRARY_PATH
 /Users/myuser/lib:/usr/local/lib:/lib:/usr/lib

Including, restart console and restart the machine, I'm running out of solutions, any idea how I can solve it?

Answer 1

Finally, I have been able to run Trac accessing my old tickets database stored in PostgreSQL 9.2

... After a couple of years of attempts, and a couple of upgrades from Mavericks to Yosemite and then to El Capitan, this has been the solution:

Step 1: Change owner of /usr/local folder

sudo chown -R $(whoami):admin /usr/local

Step 2: Update Path

PG_HOME=/Library/PostgreSQL/9.2
PATH=$PATH:$PG_HOME/bin

Step 3: Reinstall psycopg2

pip uninstall psycopg2
pip install psycopg2

Step 4: Update relative paths used by psycopg2

sudo install_name_tool -change libpq.5.dylib /Library/PostgreSQL/9.2/lib/libpq.5.dylib /Library/Python/2.7/site-packages/psycopg2/_psycopg.so
sudo install_name_tool -change libcrypto.1.0.0.dylib /Library/PostgreSQL/9.2/lib/libcrypto.1.0.0.dylib /Library/Python/2.7/site-packages/psycopg2/_psycopg.so
sudo install_name_tool -change libssl.1.0.0.dylib /Library/PostgreSQL/9.2/lib/libssl.1.0.0.dylib /Library/Python/2.7/site-packages/psycopg2/_psycopg.so