cx_Oracle.InterfaceError: Unable to acquire Oracle environment handle Mac

Question

I have cx_Oracle installed and I can successfully import it. But when I try to establish an Oracle connection, I get this error:

Traceback (most recent call last): File "<stdin>", line 1, in <module> cx_Oracle.InterfaceError: Unable to acquire Oracle environment handle

My operating system is MacOSX, and my ORACLE_HOME is pointing to instantclient_11_2.

Answer 1

First thing first.

Check if your cx_oracle is built for the exactly same version as your Oracle client.

import cx_Oracle
cx_Oracle.clientversion()

This should return the version it's expecting to find.

If the versions differ, you should rebuild it against the correctly version.

Answer 2

For instant client, do not set ORACLE_HOME. Instead follow these instructions:

cd $HOME
mkdir -p lib
cd lib
cp /the/location/to/instantclient_11_2/*dylib* .
ln -s libclntsh.dylib.11.1 libclntsh.dylib

If you are able to use Instant Client 12.1 things are a bit simpler

cd $HOME
mkdir -p lib
cd lib
ln -s /the/location/to/instantclient_12_1/libclntsh.dylib.12.1 libclntsh.dylib

If you also download and extract the SQL*Plus package you can verify that your client installation is working properly.