How can I find a resource file installed with setuptools data_files?

Question

Problem

If I am installing a python package with pip and setuptools, and need to include a config file, this can be done with the setup argument data_files.

When installed with pip, this will install the file in a sensible location, such as on a Linux system at /usr/local/ as root or $HOME/.local with a non-root installation.

However I cannot seem to find a programmatic way to then determine the location to read the file in the python application.

Solutions that don't work

• A similar question here suggested using package_data instead of data_files which then allows you to find the file relative to the python file, however burying configuration files into python's site-packages directory hardly seems like a good user experience.

• One suggested approach is to use sys.prefix, however this always returns the location of a root install, so if a user installs the package without root permissions, this will fail. sys.base_prefix has the same behaviour.

• I have also looked at using the pkg_resources library, but this also returns the path to the site-packages install location, not the config location. importlib.resources has the same behaviour.

Question

Is there a solution to finding the location of this installed config file that:

• is cross platform;
• works for both root and non-root installation;
• allows for the config file to be placed somewhere sensible (not in site-packages);
• doesn't require manually encoding all the possible paths?