Dynamically import Python module with Windows and Linux

I'm trying to dynamically import a Python module using importlib.

My project is an Azure function app and has the following file structure:

Shared_Code/
├── __init__.py
├── model.py
└── rule_engine.py

In the file rule_engine.py I'm trying to import model.py:

logging.info(__name__)
importlib.import_module(
    'Shared_Code.model', package=None
)

The above code prints

__app__.Shared_Code.rule_engine.py

and imports the module correctly on Linux and Azure Cloud.

However, when executing the exact same code on Windows I get an error that the module Shared_Code could not be found.

I've then used the following

importlib.import_module(
    '__app__.Shared_Code.model', package=None
)

which works on both, but breaks when running it on Azure Cloud.

Is there a generic solution for this without having to perform manual checks and if-clauses depending on the OS?

You can try to import model using a relative path:

importlib.import_module('.model', package='Shared_Code')

Edit: After some research, I'm concluding that this is an Azure issue, not a Python one.

There isn't a single coincidence of the string __app__ in the full CPython code.

There is, however, this azure-functions-python-worker PR where the __app__ top-level module is implemented for absolute imports.

I guess this is a bug in azure-functions-python-worker, or whatever Azure platform you're working on, where they have different behavior between Linux and Azure Cloud VS Windows.

The only things I can think you can do are:

• See if there is some configuration in your Azure service, maybe in Windows is something different by default (I don't work with Azure platform, sorry).
• Fill an issue in azure-functions-python-worker, trying to include a minimal reproducible example, and see what they think about (maybe they have the answer, maybe you found a bug).
• The Pythonic solution: import the module without __app__ inside a try/except ModuleNotFoundError, and if it fails import it again with __app__:

try:
    importlib.import_module(
        'Shared_Code.model', package=None
    )
except ModuleNotFoundError:
    # In Windows, __app__ is mandatory
    importlib.import_module(
        '__app__.Shared_Code.model', package=None
    )

I know this last one is exactly what you're asking for not to do, but if it's a platform problem (and I'm pretty sure it is) there is nothing more you can do except to deal with it.