Python wheel: "ModuleNotFoundError" after installing package

Question

OS: Windows 7

Python: 3.6

I'm trying to create and installing a python wheel package. The building works fine but when i import the module into project after installing it, i get a "ModuleNotFound" error. My project has the following structure:

my_lib/
    __init__.py
    phlayer/
        __init___.py
        uart.py
    utils/
        __init___.py
        ctimer.py 

My setup.py for creating the wheel package:

import setuptools

with open("README.md", "r") as fh:
long_description = fh.read()

setuptools.setup(
    name="my_lib",
    version="0.0.1",
    author="",
    author_email="",
    description="",
    packages=setuptools.find_packages(),
    classifiers=(
        "Programming Language :: Python :: 3",
        "License :: OSI Approved :: MIT License",
        "Operating System :: OS Independent",
    ),
)

In uart.py i do:

from utils import ctimer

After installing i import the package into another project:

#Test.py

from my_lib.phlayer.uart import Uart

def main(args=None):
    pass

if __name__ == "__main__":
    main()

And i get the error:

  File "C:/.../.../.../Test.py", line 9, in <module>
from my_lib.phlayer.uart import Uart
File "C:\...\...\...\...\...\...\test\env\lib\site-packages\my_lib\phlayer\uart.py", line 3, in <module>
from utils import ctimer
ModuleNotFoundError: No module named 'utils'

So it seems that python cannot find the correct module in the other package. Do i need to specify the correct paths in the setup.py before creating the wheel package?

Rappel

Answer 1

You have to specify full module names:

from my_lib.utils import ctimer

Putrid

Ok that worked. But now i have the problem that python cannot find the modules in the actual project. When i execute my_lib\my_lib.py (for testing) i get the error: ModuleNotFoundError: No module named my_lib. So why in this case python cannot find the module? – Rappel

What do you mean execute my_lib\my_lib.py? python my_lib\my_lib.py? Isee 2 problems here: 1. Wrong PYTHONPATH. 2. Script my_lib.py named the same as the package and it shadows the package (Python prepends its path to sys.path). – Putrid

No, the script is not named the same as the package (named it only for explanation so lets say the name is my_lib/test.py). The thing is when i run the script test.py i get the mentioned error when i use full module names. So do i have to add ...\...\...\my_lib' to PYTHONPATH if i use full package names (like: from my_lib.utils import ctimer)? Why python can find the module if i use from utils import ctimer when i run the project directly but cannot find the module if i creating and importing it as a wheel package? – Rappel

Because when you run my_lib/test.py python adds directory my_lib/ to sys.path and import utils finds utils in sys.path. After installation utils is not in sys.path — but my_lib is. – Putrid