Confit: painless YAML config files that Just Work

I'm tired of fiddling around with ConfigParser. I don’t even really like INI syntax. I'm tired of writing boilerplate code to check for missing values, fall back to defaults, override config values with command-line options, and all that. I think a configuration library should be able to handle a lot more for me.

So I'm writing Confit to magically take care of defaults, overrides, type checking, command-line integration, human-readable errors, and standard OS-specific locations. The configuration files will be based on YAML, which is a great syntax for writing down data.

What It Does

Here’s what Confit brings to the table:

• An utterly sensible API resembling dictionary-and-list structures but providing transparent validation without lots of boilerplate code. Type config['num_goats'].get(int) to get the configured number of goats and ensure that it’s an integer.
• Combine configuration data from multiple sources. Using layering, Confit allows user-specific configuration to seamlessly override system-wide configuration, which in turn overrides built-in defaults. An in-package config_default.yaml can be used to provide bottom-layer defaults using the same syntax that users will see. A runtime overlay allows the program to programmatically override and add configuration values.
• Look for configuration files in platform-specific paths. Like $XDG_CONFIG_HOME or ~/.config on Unix; "Application Support" on Mac OS X; %APPDATA% on Windows. Your program gets its own directory, which you can use to store additional data. You can transparently create this directory on demand if, for example, you need to initialize the configuration file on first run. And an environment variable can be used to override the directory's location.
• Integration with command-line arguments via argparse or optparse from the standard library. Use argparse's declarative API to allow command-line options to override configured defaults.

Using Confit

Confit’s documentation describes its API in detail.

Author

Confit is being developed by Adrian Sampson. It’s not done yet, but you’re welcome to use it under the terms of the MIT license. I'm building Confit to use it with a future version of beets.