Config framework

[chris-langfield]

Some things we want to be able to do with a config system after talking with @garrettwrong:
1 - Automatically detect config file in package directory. In particular, we want automatic path searching. For instance, first look for a config.ini in the working directory, then in the home directory, finally defaulting to a config file shipped with the package.
2 - A simple file format. We currently use .ini along with the standard library's configparser. Other options are YAML, TOML, or even .py
3 - We may want an environment variable set to path to config file?
4- We want to be able to ship a GPU config file ready to go

Some notes on the options out there:

• configparser: From what I can tell, this does not implement 1) above. It could be quite involved to write a cross-platform path search
• confuse: This is for YAML. We have heard good things from RC's Python expert
• dynaconf: This is popular on Reddit and StackOverflow threads, but looks like it's probably overkill. Also seems to have partly dropped 3.7 support
• config-path This might do what we want as far as cross-platform path search. It hasn't been updated in a while but looks official and is marked as "production/stable" on PyPI.

configparser + config-path + INI's is jumping out at me as the simplest solution to look into first.

[chris-langfield]

Rolling our own environment variable code seems easier to me than the cross-platform path search. Maybe we can still do this even if we use a package that doesn't implement env variable stuff. configparser doesn't seem to have it built in

[garrettwrong]

Hey Chris, thanks for putting this info together and asking our RSE friend.

I took a look at confuse. I like the way they are marketing the overrides, but the API seemed a bit much for what we need... and I'd need to hunt for simple working examples, which is not a good sign. I will look at dynaconf, since we might be off 3.7 soon enough anyway...

From our chat today, I think we confirmed we are just looking to config numerical backends and logging. Everything else should probably be in our code/classes. The logging potentially has a fair amount of config.

[janden]

Matplotlib approach: https://matplotlib.org/stable/tutorials/introductory/customizing.html

[garrettwrong]

Leaning towards confuse, though I would prefer it had more widespread adoption. I will try to implement it this afternoon and we can see what it looks like.