Plugin Manager

This is a plugin loader for Ruby. Features:

• dependencies
• versioning
• multiple plugin sources
• safe against plugins with broken code
• plugin code reloading

It is not tied to Rubygems or Rails. A plugin is any directory with a plugin.rb file inside that looks like this:

Plugin.define do
  name         "Extras"
  version      "1.0"
  
  # the file to load to load the plugin. It is expected to be an .rb
  # file relative to this definition
  file         "extras"
  
  # this is an object that is defined by the plugin code
  object       "App::Extras"
  
  # Dependencies of the plugin
  dependencies "core", ">=1.0",
               "fonts", ">=0.5, <1.9",
               "debug", ">0, !=0.95, < 2"
end

See the spec/fixtures/example/ directory for an example of a set of plugins.

This directory of plugins can be loaded with:

manager = PluginManager.new
manager.add_plugin_source("spec/fixtures/example")
manager.load

The code in the appropriate plugins will be loaded and you will then have available:

# plugins that were loaded successfully
manager.loaded_plugins

# plugins that could not be loaded because of unmet dependencies, 
# or because a more recent version was available.
manager.unloaded_plugins

# plugin.rb files that could not be read
manager.unreadable_definitions

# plugins that raised exceptions while being loaded
manager.plugins_with_errors

NB. There is a BIG difference between this and say, Rubygems, in that plugin_manager will ONLY EVER LOAD THE MOST RECENT VERSION OF A PLUGIN. Older versions essentially DON'T EXIST from the point of view of the plugin_manager.

License

MIT