Where to place absolute paths in a python project?

I have the following project structure

ts_tools
    /bin
    /docs
    /lib
    /ts_tools
        /data_transfer
            /tests
            data_import.py
            __init__.py
        /data_manipulation
            /tests
            data_smoothing.py
            __init__.py
        __init__.py
    config.yaml.conf
    setup.py
    LICENSE
    README.md
    TODO.md

I would like to import data with the data_import.py file from an external source. I use the config.yaml.conf file to specify the absolute paths of the data with:

root_path:
    windows:
        data_fundamental: C:\\Users\\Malcom\\Data_Fundamental
        data_event: C:\\Users\\Malcom\\Data_Event
    linux:
        data_fundamental: /home/data/data_fundamental
        data_event: /home/data/data_event

The respective paths should be available for all tools in the ts_tools package (i.e. data_import.py and data_smoothing.py). Furthermore, the program should identify the os and choose the path structure accordingly.

I know how to set the paths with the yaml file using

import yaml

with open("config.yaml.conf", "r") as ymlfile:
    cfg = yaml.load(ymlfile)

and I know how to discriminate between the os with

if platform.system().lower() == 'windows':
    ROOT_DATA_PATH = cfg['windows']
else:
    ROOT_DATA_PATH = cfg['linux']

but I don't know where to place these code snippets. I don't think that it is appropriate to use it in the setup.py file. On the other hand I consider it inappropriate to specify a new .py file. What is a good design structure for this problem? Where should a specify absolute file paths? Is my ansatz a step in the right direction?

Thank you in advance.

Solution

In this case, you can make it relative to the home directory, so you can have ~/data_fundamental and ~/data_event (Which should be equivalent on both platforms). You can expand this with os.path.expandhome

import os.path

def get_path(s):
    return os.path.normpath(os.path.normcase(
        os.path.expanduser(os.path.expandvars(s))
    ))

# get_path('~/data_fundamental') on Windows:
#    r'c:\users\malcom\data_fundamental'
# get_path('~/data_fundamental') on Linux:
#    r'/home/data/data_fundamental'
# (Assuming your username on Windows is Malcolm
#  and on Linux is data and you haven't changed
#  the default home path)

In any case, having two different setup things might be overly confusing, and you should expand ~ and %VARS% and ${VARS} anyways to make setting it up easier and run as expected.

Your other alternatives include:

Reading from environment variables
Writing it in setup.py (You should probably allow some way to change where the config file is as setup.py might put it in a write-protected location)

You could also not have a default at all, and when not given either make a default based on sys.platform() or raise an error message telling the user to set it.