Mandrel should offer a configuration class variant that expects to get its attributes from environment variables.

There are a number of ways one could go about this. Certainly would could provide functionality to reduce environment variables down to a basic native (nested) dictionary, which could be used as the initial dict for a Configuration instance. However, it would probably be more idiomatic if the thing were a configuration class in its own right, which all other configuration extensions could use just by chaining.

The point is we want to be able to say things like:

• this variable is this attribute, and it should be an integer
• this variable is this attribute, and it should be a comma-separated list of strings
• variables with this prefix are a nested dict (which is a complicated case)

And so on.

This requires some thought.