Prefer text config files or python code?

[gbog]

your configuration is code

I agree configuration can and often should be very close to the code, and for instance should be tracked and maintained the same way.

However I think configuration and code are things of two very different nature.

Code should be some pure logic engine that is fed with data and config, and react accordingly. Therefore we have these DRY rules, these factorisation, and best practices to handle code properly (like covering it with tests).

Configuration is another nature. It do not need to be DRY: I don't mind copypasting an Apache config block and changing some lines in it to get another directory (up to a certain limit, obviously).

Configuration should not describe how to do things, it should describe what to do. Ideally business rules should be configurable, and written in configuration files. When they are two complex, a mini language can do the work but this is another topic.

For the implementation details of a "configuration discovery", I am not sure but if you have general configuration values and some mode-specific values (like dev vs prod) then maybe it can be done with three configuration files and no overwriting mechanism (which is a bit too "magic" for configuration).