Question

Some background info:
I’m trying to run a server program in python 2.5.1 (the version the server was written for and tested on). The program needs the OpenSSL library for some of its functions. I installed python 2.5.1 from source as the yum repository for the Amazon Linux instance I’m running on does not have the version of python I need.

When I try to run the server with python 2.5.1 I get the following import error:

Traceback (most recent call last):  
File "<stdin>", line 1, in <module>  
ImportError: No module named OpenSSL

I know that the OpenSSL libraries are installed as I can import them into Python 2.6 (the version of python installed by yum). It’s just that my python 2.5.1 installation can’t see them.

I have also installed pyOpenSSL via yum with no luck.

Answer 1

installed python libraries are specific to a particular version. so the pyOpenSSL you installed from yum will be for the system python. you need to install a separate instance of pyOpenSSL for the alt-installed 2.5 python.

if you use python2.5 to install distutils then you’ll find that you have an easy_install-2.5 that you can use: easy_install-2.5 pyopenssl (or similar). but note that may also install a new version of easy_install, overwriting the existing one for the system python (if you have one). to use distutils with the existing package use easy_install-2.7 (if it’s python 2.7).

does that make sense? basically, each python is distinct and needs its own set of libraries. in contrast, easy_install is installed globally, but there is a version-specific copy of easy_install for each python…!

if you want to avoid the mess with easy_install, you can use virtualenv. create a new environment for 2.5, enable that, and you can install the pyopenssl in there (using the easy_install from the environment). that may sound more complicated if you’ve never ysed virtualenv, but if you give it a little time to understand it will likely work out better in the long-term.