Add Support for Cascading LogLevel Configuration

[jonnyreeves]

Add Support for Cascading LogLevel Configuration

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You could have a look at how debug does this.

Debug has no global logger, only named loggers. And it is basically just a list, there is no hierarchy.
But it can simulate hierarchy through naming conventions. They recommend using colon : to separate levels:

var debug = require('debug')
var log = require('my-app:my-module')
log('Hello!')

By default, this would not produce any output, but you can enable loggers using a pattern:

debug.enable('my-app:my-module') // enables only the one module
debug.enable('my-app:*') // enables every submodule of my-app

They translate the pattern and then use simple regex pattern matching on the name to determine if the logger is enabled or not. It works surprisingly well.