ImportError: No module named - Python

I have a python application with the following directory structure:

src
 |
 +---- main
 |
 +---- util
 |
 +---- gen_py
         |
         +---- lib

In the package main, I have a python module named MyServer.py which has an import statement like:

from gen_py.lib import MyService

In order for this statement to work, I placed the following line at the beginning of MyServer.py:

import sys
sys.path.append('../gen_py/lib')

When I run MyServer.py in the terminal, I get the following error:

ImportError: No module named gen_py.lib

What I am missing here?

Your modification of sys.path assumes the current working directory is always in main/. This is not the case. Instead, just add the parent directory to sys.path:

import sys
import os.path

sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
import gen_py.lib

Don't forget to include a file __init__.py in gen_py and lib - otherwise, they won't be recognized as Python modules.

For the Python module import to work, you must have "src" in your path, not "gen_py/lib".

When processing an import like import gen_py.lib, it looks for a module gen_py, then looks for a submodule lib.

As the module gen_py won't be in "../gen_py/lib" (it'll be in ".."), the path you added will do nothing to help the import process.

Depending on where you're running it from, try adding the relative path to the "src" folder. Perhaps it's sys.path.append('..'). You might also have success running the script while inside the src folder directly, via relative paths like python main/MyServer.py