python import path: packages with the same name in different folders

Question

I am developing several Python projects for several customers at the same time. A simplified version of my project folder structure looks something like this:

Answer 1

This is the solution to my problem, albeit it might not be obvious at first.

In my projects, I have now introduced a convention of one namespace per customer. In every customer folder (cust1, cust2, etc.), there is an __init__.py file with this code:

import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)

All the other __init__.py files in my packages are empty (mostly because I haven't had the time yet to find out what else to do with them).

As explained here, extend_path makes sure Python is aware there is more than one sub-package within a package, physically located elsewhere and - from what I understand - the interpreter then does not stop searching after it fails to find a module under the first package path it encounters in sys.path, but searches all paths in __path__.

I can now access all code in a consistent manner criss-cross between all projects, e.g.

from cust1.proj1.pack1.mod1 import something
from cust3.proj4.pack1.mod4 import something_else
from cust3.proj1.pack4.mod4 import yet_something_else

On a downside, I had to create an even deeper project folder structure:

/path/
  to/
    projects/
      cust1/
        proj1/
          Development/
            code/
              python/
                cust1/
                  __init__.py   <--- contains code as described above
                  proj1/
                    __init__.py <--- empty
                    pack1/
                    __init__.py <--- empty
                    mod1.py

but that seems very acceptable to me, especially considering how little effort I need to make to maintain this convention. sys.path is extended by /path/to/projects/cust1/proj1/Development/code/python for this project.

On a sidenote, I noticed that of all the __init__.py files for the same customer, the one in the path that appears first in sys.path is executed, no matter from which project I import something.