Store machine ID in "id" file in data directory.

Instead of storing an "active" hash in the local_data of an Environment,
we now place the ID of a machine in the "id" file of the machine data
directory. This file is read upon re-instantiation in order to load the
proper state.

lib/vagrant/environment.rb

@@ -223,10 +223,15 @@ module Vagrant
       # Get the provider configuration from the final loaded configuration
       provider_config = config.vm.providers[provider].config
 
+      # Determine the machine data directory and pass it to the machine.
+      # XXX: Permissions error here.
+      machine_data_path = @local_data_path.join("machines/#{name}/#{provider}")
+      FileUtils.mkdir_p(machine_data_path)
+
       # Create the machine and cache it for future calls. This will also
       # return the machine from this method.
       @machines[cache_key] = Machine.new(name, provider_cls, provider_config,
-                                         config, box, self)
+                                         config, machine_data_path, box, self)
     end
 
     # This returns a list of the configured machines for this environment.
@@ -317,16 +322,6 @@ module Vagrant
       @global_data ||= DataStore.new(File.expand_path("global_data.json", home_path))
     end
 
-    # Loads (on initial access) and reads data from the local data
-    # store. This file is always at the root path as the file "~/.vagrant"
-    # and contains a JSON dump of a hash. See {DataStore} for more
-    # information.
-    #
-    # @return [DataStore]
-    def local_data
-      @local_data ||= DataStore.new(@local_data_path.join("environment_data"))
-    end
-
     # The root path is the path where the top-most (loaded last)
     # Vagrantfile resides. It can be considered the project root for
     # this environment.

lib/vagrant/machine.rb

@@ -15,6 +15,11 @@ module Vagrant
     # @return [Object]
     attr_reader :config
 
+    # Directory where machine-specific data can be stored.
+    #
+    # @return [Pathname]
+    attr_reader :data_dir
+
     # The environment that this machine is a part of.
     #
     # @return [Environment]
@@ -50,19 +55,22 @@ module Vagrant
     # @param [Object] provider_config The provider-specific configuration for
     #   this machine.
     # @param [Object] config The configuration for this machine.
+    # @param [Pathname] data_dir The directory where machine-specific data
+    #   can be stored. This directory is ensured to exist.
     # @param [Box] box The box that is backing this virtual machine.
     # @param [Environment] env The environment that this machine is a
     #   part of.
-    def initialize(name, provider_cls, provider_config, config, box, env, base=false)
+    def initialize(name, provider_cls, provider_config, config, data_dir, box, env, base=false)
       @logger = Log4r::Logger.new("vagrant::machine")
       @logger.info("Initializing machine: #{name}")
       @logger.info("  - Provider: #{provider_cls}")
       @logger.info("  - Box: #{box}")
 
-      @box    = box
-      @config = config
-      @env    = env
-      @name   = name
+      @box             = box
+      @config          = config
+      @data_dir        = data_dir
+      @env             = env
+      @name            = name
       @provider_config = provider_config
 
       # Read the ID, which is usually in local storage
@@ -72,7 +80,10 @@ module Vagrant
       if base
         @id = name
       else
-        @id = @env.local_data[:active][@name.to_s] if @env.local_data[:active]
+        # Read the id file from the data directory if it exists as the
+        # ID for the pre-existing physical representation of this machine.
+        id_file = @data_dir.join("id")
+        @id = id_file.read if id_file.file?
       end
 
       # Initializes the provider last so that it has access to all the
@@ -176,20 +187,20 @@ module Vagrant
     #
     # @param [String] value The ID.
     def id=(value)
-      @env.local_data[:active] ||= {}
+      # The file that will store the id if we have one. This allows the
+      # ID to persist across Vagrant runs.
+      id_file = @data_dir.join("id")
 
       if value
-        # Set the value
-        @env.local_data[:active][@name] = value
+        # Write the "id" file with the id given.
+        id_file.open("w+") do |f|
+          f.write(value)
+        end
       else
-        # Delete it from the active hash
-        @env.local_data[:active].delete(@name)
+        # Delete the file, since the machine is now destroyed
+        id_file.delete
       end
 
-      # Commit the local data so that the next time Vagrant is initialized,
-      # it realizes the VM exists (or doesn't).
-      @env.local_data.commit
-
       # Store the ID locally
       @id = value
 

test/unit/vagrant/machine_test.rb

@@ -1,3 +1,5 @@
+require "pathname"
+
 require File.expand_path("../../base", __FILE__)
 
 describe Vagrant::Machine do
@@ -13,6 +15,7 @@ describe Vagrant::Machine do
   let(:provider_config) { Object.new }
   let(:box)      { Object.new }
   let(:config)   { env.config_global }
+  let(:data_dir) { Pathname.new(Tempdir.new.path) }
   let(:env)      do
     # We need to create a Vagrantfile so that this test environment
     # has a proper root path
@@ -28,7 +31,8 @@ describe Vagrant::Machine do
 
   # Returns a new instance with the test data
   def new_instance
-    described_class.new(name, provider_cls, provider_config, config, box, env)
+    described_class.new(name, provider_cls, provider_config,
+                        config, data_dir, box, env)
   end
 
   describe "initialization" do
@@ -57,7 +61,8 @@ describe Vagrant::Machine do
 
         # Initialize a new machine and verify that we properly receive
         # the machine we expect.
-        instance = described_class.new(name, provider_cls, provider_config, config, box, env)
+        instance = described_class.new(name, provider_cls, provider_config,
+                                       config, data_dir, box, env)
         received_machine.should eql(instance)
       end