Configuration Facility Design

Background

Software needs configuration to operate (except for very basic or one off software with hard coded configuration).

Requirements

• Support for configuration sources
  • Command line switches
    • Must not interfere with arbitrary processing of command line arguments by the main program
  • Environment variables
  • Structured files
  • Maybe: runtime configuration using API
• Ability to provide different data types, not only strings (as typical for environment variables and command line switches).

Design (WIP)

• Priorities of configuration source (low to high)
  • Configuration files
    • System-wide
    • Home directory (somewhere under home directory to be more specific)
  • Environment variables
  • Command line switches

TODO / Open issues

• Take another look at Spring for ideas
• Which other frameworks to look at?
• Do we need schema on order to know how to parse?
• Consider dependency injection (where the types/objects are configured by this configuration system)
• Check .local folder and do more general research on where config files should go
• Debugging is already configured using the DEBUG environment variable
  • Think about compatibility
  • Design switching debugging configuration to the new (this) system
• Consider overriding/merging behaviour for lists (Arr) and dictionaries (Hash)... or any other types of containers
• Consider ++ as end-of-configuration marker for command line arguments.
  • ... but not after -- ?

Additional information

• See config() method