What is it?

Prefer is a library for helping you manage application configurations while providing your users the flexibility of using whatever configuration format fits their needs.

It provides a set of interfaces which provide standard methods for reading arbitrary project configuration data. This can vary from simple cases like JSON, to more complicated examples - such as retreiving configuration data from a database.

How do I use it?

Firstly, you'll want to install the module. This can be done easily with easy_install or pip.

easy_install prefer

Prefer is fairly simple to use. A basic use case might be that you have the following JSON configuration in settings.json:

{
  "auth": {
    "username": "user",
    "password": "pass"
  }
}

You can load these settings with the following code using promises:

import prefer

configuration = await prefer.load('settings')
username = configration.get('auth.username')

You will notice that prefer only required 'settings' as the filename. It is recommended to be given without a path or extension, because prefer takes care of looking through the filesystem for configuration files. On both Unix and Windows systems, it will look in all of the standard folders, as well as some conventional places where people like to put their configurations.

Ordering matters, so having a file in ./settings.json as well as another in /etc/settings.json is still reliable. The configuration in ./settings.json will be used first. Prefer doesn't care what format your user writes your settings in, so they can also use settings.yaml if they like.

Supported configuration formats

Along with being fully configurable to support any arbitrary data source you'd like, the following types of data can immediately be used as configuration formats upon installation of prefer:

• JSON
• YAML

Why asyncronous?

In order to supply a more-simple method of getting the configuration, many configuration tools prefer to provide a blocking method of retrieving a project configuration. One goal of prefer is to ensure that we aren't limiting users to specific use-cases - and some projects require real-time, dynamic updating of their configuration. Prefer provides all it's interfaces as asyncronous functions in order to provide that possibility without the requirement that those actions are blocking.