Writing your own config loader

Do you want to store your WSGI app config in Redis? In a TOML file? In ZooKeeper? You can do that.

You will need to decide two things:

1. A filename extension for your configuration format: for actual files, that’s easy. A JSON loader should work with foo.json files. However, if you are loading your configuration from a service, you still need to pick a filename extension; Montague uses that to dispatch to config loaders. Perhaps you will store the Redis connection info in myfile.redis, or perhaps the file doesn’t even exist and you extract the connection info from the path name.
2. Whether you need to support individual app_config, server_config, etc methods: the default INI loader supports these because the PasteDeploy INI format allows individual app configs to override global variables for that specific app.

Config loaders must provide the methods listed in the montague.interfaces.IConfigLoader interface; it’s recommended, though not required, that they actually implement the interface using zope.interface.

Montague Standard Format

The actual layout of your configuration information will obviously vary from format to format. Because of this, Montague has a standard layout you should use when implementing the montague.interfaces.IConfigLoader.config() method. You should return a dict that looks like this:

{
    "globals": {},
    "application": {},
    "composite": {},
    "filter": {},
    "server": {},
    "logging": {},
}

Of course, the dict can contain other keys as well, but those are the ones Montague cares about.