I am building a simple DB interface in Python (3.9.9) and I am using psycopg (3.0.7) to connect to my Postgres (14.1) database. Until recently, the development of this app took place on Linux, but now I am using macOS Monterey on an M1 Mac mini. This seems to be causing some troubles with ctypes, which psycopg uses extensively. The error I am getting is the following:
ImportError: no pq wrapper available.
Attempts made:
- couldn't import psycopg 'c' implementation: No module named 'psycopg_c'
- couldn't import psycopg 'binary' implementation: No module named 'psycopg_binary'
- couldn't import psycopg 'python' implementation: libpq library not found
Based on the source code of psycopg, this is an error of ctypes not being able to util.find_library libpq.dylib. Postgres is installed as Postgres.app, meaning that libpq.dylib's path is
/Applications/Postgres.app/Contents/Versions/14/bin/lib
I have tried adding this to PATH, but it did not work. I then created a symlink to the path in /usr/local/lib, but (unsurprisingly) it also did not work. I then did some digging and found this issue describing the same problem. I am not a big macOS expert, so I am unsure on how to interpret some of the points raised. Do I need to add the path to the shared cache? Also, I do not want to fork the Python repo and implement the dlopen() method as suggested, as it seems to lead to other problems.
Anyhow, is there a solution to quickly bypass this problem? As an additional reference, the code producing the above error is just:
import psycopg
print(psycopg.__version__)
I had this problem but the solution was suggested to me by this answer to a related question: try setting envar DYLD_LIBRARY_PATH to the path you identified.
NB, to get it working myself, I:
/Applications/Postgres.app/Contents/Versions/latest/lib and