fitter

Dependency injection library for Clojure.

Status

• [x] Start/stop system of components.
• [x] Mount running instances.
• [x] Suspend/resume components.
• [x] Parallel start/stop.

Terminology

• instance
  • something useful instantiated :-)
• component
  • describe how to initialize/destroy instance of something.
• registry
  • map of keys and components
• system
  • collection of dependent component instances.

Overview

• Components are just functions or maps with ::component/start/::component/stop! keys.
• Component start function receives system map with keys known in component registry.
• The registry is a map of components where keys are unique and known in the system context. These keys are referred in component/start function argument.
• Dependency is formed when component access system key in start function.
• System “atom” holds the state of running component instances and can be started, stopped, restarted etc.

Examples

• app-system
• How to log
• How to mount
• How to parallel
• How to suspend

TODO

• Optional parallel start/stop of system components.
• Experimental: lazy system which does not require explicit start! (?).