commands/box: Extract box removal code from `box remove` command into a builtin action

lib/vagrant/action.rb

@@ -8,7 +8,8 @@ module Vagrant
     # Builtin contains middleware classes that are shipped with Vagrant-core
     # and are thus available to all plugins as a "standard library" of sorts.
     module Builtin
-      autoload :BoxAdd,  "vagrant/action/builtin/box_add"
+      autoload :BoxAdd,    "vagrant/action/builtin/box_add"
+      autoload :BoxRemove, "vagrant/action/builtin/box_remove"
       autoload :Call,    "vagrant/action/builtin/call"
       autoload :Confirm, "vagrant/action/builtin/confirm"
       autoload :ConfigValidate, "vagrant/action/builtin/config_validate"
@@ -43,5 +44,14 @@ module Vagrant
         b.use Builtin::WriteBoxInfo
       end
     end
+
+    # This is the action that will remove a box given a name (and optionally
+    # a provider). This middleware sequence is built-in to Vagrant. Plugins
+    # can hook into this like any other middleware sequence.
+    def self.action_box_remove
+      Builder.new.tap do |b|
+        b.use Builtin::BoxRemove
+      end
+    end
   end
 end

lib/vagrant/action/builtin/box_remove.rb

@@ -0,0 +1,38 @@
+require "log4r"
+
+module Vagrant
+  module Action
+    module Builtin
+      # This middleware will remove a box for a given provider.
+      class BoxRemove
+        def initialize(app, env)
+          @app    = app
+          @logger = Log4r::Logger.new("vagrant::action::builtin::box_remove")
+        end
+
+        def call(env)
+          box_name     = env[:box_name]
+          box_provider = env[:box_provider].to_sym
+
+          box = nil
+          begin
+            box = env[:box_collection].find(box_name, box_provider)
+          rescue Vagrant::Errors::BoxUpgradeRequired
+            @env.boxes.upgrade(box_name)
+            retry
+          end
+
+          raise Vagrant::Errors::BoxNotFound, :name => box_name, :provider => box_provider if !box
+          env[:ui].info(I18n.t("vagrant.commands.box.removing",
+                              :name => box_name,
+                              :provider => box_provider))
+          box.destroy!
+
+          # Passes on the removed box to the rest of the middleware chain
+          env[:box_removed] = box
+          @app.call(env)
+        end
+      end
+    end
+  end
+end

plugins/commands/box/command/remove.rb

@@ -34,19 +34,11 @@ module VagrantPlugins
             argv[1] = providers[0] || ""
           end
 
-          b = nil
-          begin
-            b = @env.boxes.find(argv[0], argv[1].to_sym)
-          rescue Vagrant::Errors::BoxUpgradeRequired
-            @env.boxes.upgrade(argv[0])
-            retry
-          end
-
-          raise Vagrant::Errors::BoxNotFound, :name => argv[0], :provider => argv[1].to_sym if !b
-          @env.ui.info(I18n.t("vagrant.commands.box.removing",
-                              :name => argv[0],
-                              :provider => argv[1]))
-          b.destroy!
+          @env.action_runner.run(Vagrant::Action.action_box_remove, {
+            :box_name     => argv[0],
+            :box_provider => argv[1],
+            :box_state_file => StateFile.new(@env.home_path.join('boxes.json'))
+          })
 
           # Success, exit status 0
           0