Plugins. Documentation coming shortly.

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## 0.6.0 (unreleased)
 
+  - **Plugins** have landed. Plugins are simply gems which have a `vagrant_init.rb`
+    file somewhere in their load path. Please read the documentation on
+    vagrantup.com before attempting to create a plugin (which is very easy)
+    for more information on how it all works and also some guidelines.
   - `vagrant package` now takes a `--vagrantfile` option to specify a
     Vagrantfile to package. The `--include` approach for including a Vagrantfile
     no longer works (previously built boxes will continue to work).

lib/vagrant.rb

@@ -14,6 +14,7 @@ module Vagrant
   autoload :Config,        'vagrant/config'
   autoload :DataStore,     'vagrant/data_store'
   autoload :Errors,        'vagrant/errors'
+  autoload :Plugin,        'vagrant/plugin'
   autoload :Util,          'vagrant/util'
 
   module Command
@@ -48,5 +49,6 @@ Vagrant::Util::GlobLoader.glob_require(libdir, %w{
   downloaders/base provisioners/base provisioners/chef systems/base
   hosts/base})
 
-# Initialize the built-in actions
+# Initialize the built-in actions and load the plugins.
 Vagrant::Action.builtin!
+Vagrant::Plugin.load!

lib/vagrant/plugin.rb

@@ -0,0 +1,40 @@
+require "rubygems"
+
+module Vagrant
+  class Plugin
+    # The array of loaded plugins.
+    @@plugins = []
+
+    attr_reader :gemspec
+    attr_reader :file
+
+    # Loads all the plugins for Vagrant. Plugins are currently
+    # gems which have a "vagrant_init.rb" somewhere on their
+    # load path. This file is loaded to kick off the load sequence
+    # for that plugin.
+    def self.load!
+      # Look for a vagrant_init.rb in all the gems, but only the
+      # latest version of the gems.
+      Gem.source_index.latest_specs.each do |spec|
+        file = Gem.searcher.matching_files(spec, "vagrant_init.rb").first
+        next if !file
+
+        @@plugins << new(spec, file)
+      end
+    end
+
+    # Returns the array of plugins which are currently loaded by
+    # Vagrant.
+    def self.plugins; @@plugins; end
+
+    # Initializes a new plugin, given a Gemspec and the path to the
+    # gem's `vagrant_init.rb` file. This should never be called manually.
+    # Instead {load!} creates all the instances.
+    def initialize(spec, file)
+      @gemspec = spec
+      @file = file
+
+      load file
+    end
+  end
+end

test/vagrant/plugin_test.rb

@@ -0,0 +1,9 @@
+require "test_helper"
+
+class PluginTest < Test::Unit::TestCase
+  setup do
+    @klass = Vagrant::Plugin
+  end
+
+  # This is a pretty tough class to test. TODO.
+end