A new configuration discovery strategy.

[hernantz]

If I write an app which has code in /opt/app and I would like users to optionally put a config.ini in /etc/app/, there is no way to do it through prettyconf's current discovery strategy.
It would be nice to be able to configure this behavior.
I imagine something like:

from prettyconf.configuration import env_vars, dirs, recursive

config.strategies = [
     env_vars, 
     dirs('/etc/app', '~/.configs/app'], 
     recursive(root_dir='/', starting_path='./')
]

The above snippet means that a config variable would be first checked within the environment variables,
if it is not found there, it would look at /etc/app, etc.

What do you think? I'm currently facing this issue and I'm willing to work on this.

[osantana]

I like this idea. But I'd use classes to implement strategies just to keep uniformity on API:

from prettyconf.discovery import Environment, Directory, Search, CommandLine

config.strategies = [
    CommandLine(...),  # nice-to-have: enable configuration using command-line/argparse
    Environment(),
    Directory('~/.config/app', '/etc/app'),
    Search(root_dir='/', starting_path=os.path.dirname(__file__)),
]

[hernantz]

Sounds good to me.
What are your thoughts on having something similar to Directory() called Files() that would look for configuration files with specific names:

Files('~/.config/app/app.cfg', '/etc/app/app.cfg')

CommandLine(...) strategy is very interesting too, maybe it can receive sys.argv or maybe something else after the args parsing has been handled by another library?