vaguerent/lib/vagrant/environment.rb

require 'fileutils'
require 'json'
require 'pathname'
require 'set'
require 'thread'

require "checkpoint"
require 'log4r'

require 'vagrant/util/file_mode'
require 'vagrant/util/platform'
require "vagrant/vagrantfile"
require "vagrant/version"

module Vagrant
  # A "Vagrant environment" represents a configuration of how Vagrant
  # should behave: data directories, working directory, UI output,
  # etc. In day-to-day usage, every `vagrant` invocation typically
  # leads to a single Vagrant environment.
  class Environment
    # This is the current version that this version of Vagrant is
    # compatible with in the home directory.
    #
    # @return [String]
    CURRENT_SETUP_VERSION = "1.5"

    DEFAULT_LOCAL_DATA = ".vagrant"

    # The `cwd` that this environment represents
    attr_reader :cwd

    # The persistent data directory where global data can be stored. It
    # is up to the creator of the data in this directory to properly
    # remove it when it is no longer needed.
    #
    # @return [Pathname]
    attr_reader :data_dir

    # The valid name for a Vagrantfile for this environment.
    attr_reader :vagrantfile_name

    # The {UI} object to communicate with the outside world.
    attr_reader :ui

    # This is the UI class to use when creating new UIs.
    attr_reader :ui_class

    # The directory to the "home" folder that Vagrant will use to store
    # global state.
    attr_reader :home_path

    # The directory to the directory where local, environment-specific
    # data is stored.
    attr_reader :local_data_path

    # The directory where temporary files for Vagrant go.
    attr_reader :tmp_path

    # The directory where boxes are stored.
    attr_reader :boxes_path

    # The path where the plugins are stored (gems)
    attr_reader :gems_path

    # The path to the default private key
    attr_reader :default_private_key_path

    # Initializes a new environment with the given options. The options
    # is a hash where the main available key is `cwd`, which defines where
    # the environment represents. There are other options available but
    # they shouldn't be used in general. If `cwd` is nil, then it defaults
    # to the `Dir.pwd` (which is the cwd of the executing process).
    def initialize(opts=nil)
      opts = {
        cwd:              nil,
        home_path:        nil,
        local_data_path:  nil,
        ui_class:         nil,
        vagrantfile_name: nil,
      }.merge(opts || {})

      # Set the default working directory to look for the vagrantfile
      opts[:cwd] ||= ENV["VAGRANT_CWD"] if ENV.has_key?("VAGRANT_CWD")
      opts[:cwd] ||= Dir.pwd
      opts[:cwd] = Pathname.new(opts[:cwd])
      if !opts[:cwd].directory?
        raise Errors::EnvironmentNonExistentCWD, cwd: opts[:cwd].to_s
      end
      opts[:cwd] = opts[:cwd].expand_path

      # Set the default ui class
      opts[:ui_class] ||= UI::Silent

      # Set the Vagrantfile name up. We append "Vagrantfile" and "vagrantfile" so that
      # those continue to work as well, but anything custom will take precedence.
      opts[:vagrantfile_name] ||= ENV["VAGRANT_VAGRANTFILE"] if \
        ENV.has_key?("VAGRANT_VAGRANTFILE")
      opts[:vagrantfile_name] = [opts[:vagrantfile_name]] if \
        opts[:vagrantfile_name] && !opts[:vagrantfile_name].is_a?(Array)

      # Set instance variables for all the configuration parameters.
      @cwd              = opts[:cwd]
      @home_path        = opts[:home_path]
      @vagrantfile_name = opts[:vagrantfile_name]
      @ui               = opts[:ui_class].new
      @ui_class         = opts[:ui_class]

      # This is the batch lock, that enforces that only one {BatchAction}
      # runs at a time from {#batch}.
      @batch_lock = Mutex.new

      @locks = {}

      @logger = Log4r::Logger.new("vagrant::environment")
      @logger.info("Environment initialized (#{self})")
      @logger.info("  - cwd: #{cwd}")

      # Setup the home directory
      @home_path  ||= Vagrant.user_data_path
      @home_path  = Util::Platform.fs_real_path(@home_path)
      @boxes_path = @home_path.join("boxes")
      @data_dir   = @home_path.join("data")
      @gems_path  = @home_path.join("gems")
      @tmp_path   = @home_path.join("tmp")
      @machine_index_dir = @data_dir.join("machine-index")

      # Prepare the directories
      setup_home_path

      # Run checkpoint in a background thread on every environment
      # initialization. The cache file will cause this to mostly be a no-op
      # most of the time.
      @checkpoint_thr = Thread.new do
        Thread.current[:result] = nil

        # If we disabled checkpoint via env var, don't run this
        if ENV["VAGRANT_CHECKPOINT_DISABLE"].to_s != ""
          @logger.info("checkpoint: disabled from env var")
          next
        end

        # If we disabled state and knowing what alerts we've seen, then
        # disable the signature file.
        signature_file = @data_dir.join("checkpoint_signature")
        if ENV["VAGRANT_CHECKPOINT_NO_STATE"].to_s != ""
          @logger.info("checkpoint: will not store state")
          signature_file = nil
        end

        Thread.current[:result] = Checkpoint.check(
          product: "vagrant",
          version: VERSION,
          signature_file: signature_file,
          cache_file: @data_dir.join("checkpoint_cache"),
        )
      end

      # Setup the local data directory. If a configuration path is given,
      # then it is expanded relative to the working directory. Otherwise,
      # we use the default which is expanded relative to the root path.
      opts[:local_data_path] ||= ENV["VAGRANT_DOTFILE_PATH"]
      opts[:local_data_path] ||= root_path.join(DEFAULT_LOCAL_DATA) if !root_path.nil?
      if opts[:local_data_path]
        @local_data_path = Pathname.new(File.expand_path(opts[:local_data_path], @cwd))
      end

      setup_local_data_path

      # Setup the default private key
      @default_private_key_path = @home_path.join("insecure_private_key")
      copy_insecure_private_key

      # Call the hooks that does not require configurations to be loaded
      # by using a "clean" action runner
      hook(:environment_plugins_loaded, runner: Action::Runner.new(env: self))

      # Call the environment load hooks
      hook(:environment_load, runner: Action::Runner.new(env: self))
    end

    # Return a human-friendly string for pretty printed or inspected
    # instances.
    #
    # @return [String]
    def inspect
      "#<#{self.class}: #{@cwd}>".encode('external')
    end

    # Action runner for executing actions in the context of this environment.
    #
    # @return [Action::Runner]
    def action_runner
      @action_runner ||= Action::Runner.new do
        {
          action_runner:  action_runner,
          box_collection: boxes,
          hook:           method(:hook),
          host:           host,
          machine_index:  machine_index,
          gems_path:      gems_path,
          home_path:      home_path,
          root_path:      root_path,
          tmp_path:       tmp_path,
          ui:             @ui
        }
      end
    end

    # Returns a list of machines that this environment is currently
    # managing that physically have been created.
    #
    # An "active" machine is a machine that Vagrant manages that has
    # been created. The machine itself may be in any state such as running,
    # suspended, etc. but if a machine is "active" then it exists.
    #
    # Note that the machines in this array may no longer be present in
    # the Vagrantfile of this environment. In this case the machine can
    # be considered an "orphan." Determining which machines are orphan
    # and which aren't is not currently a supported feature, but will
    # be in a future version.
    #
    # @return [Array<String, Symbol>]
    def active_machines
      # We have no active machines if we have no data path
      return [] if !@local_data_path

      machine_folder = @local_data_path.join("machines")

      # If the machine folder is not a directory then we just return
      # an empty array since no active machines exist.
      return [] if !machine_folder.directory?

      # Traverse the machines folder accumulate a result
      result = []

      machine_folder.children(true).each do |name_folder|
        # If this isn't a directory then it isn't a machine
        next if !name_folder.directory?

        name = name_folder.basename.to_s.to_sym
        name_folder.children(true).each do |provider_folder|
          # If this isn't a directory then it isn't a provider
          next if !provider_folder.directory?

          # If this machine doesn't have an ID, then ignore
          next if !provider_folder.join("id").file?

          provider = provider_folder.basename.to_s.to_sym
          result << [name, provider]
        end
      end

      # Return the results
      result
    end

    # This creates a new batch action, yielding it, and then running it
    # once the block is called.
    #
    # This handles the case where batch actions are disabled by the
    # VAGRANT_NO_PARALLEL environmental variable.
    def batch(parallel=true)
      parallel = false if ENV["VAGRANT_NO_PARALLEL"]

      @batch_lock.synchronize do
        BatchAction.new(parallel).tap do |b|
          # Yield it so that the caller can setup actions
          yield b

          # And run it!
          b.run
        end
      end
    end

    # Checkpoint returns the checkpoint result data. If checkpoint is
    # disabled, this will return nil. See the hashicorp-checkpoint gem
    # for more documentation on the return value.
    #
    # @return [Hash]
    def checkpoint
      @checkpoint_thr.join
      return @checkpoint_thr[:result]
    end

    # Makes a call to the CLI with the given arguments as if they
    # came from the real command line (sometimes they do!). An example:
    #
    #     env.cli("package", "--vagrantfile", "Vagrantfile")
    #
    def cli(*args)
      CLI.new(args.flatten, self).execute
    end

    # This returns the provider name for the default provider for this
    # environment.
    #
    # @return [Symbol] Name of the default provider.
    def default_provider(**opts)
      opts[:exclude]       = Set.new(opts[:exclude]) if opts[:exclude]
      opts[:force_default] = true if !opts.has_key?(:force_default)

      default = ENV["VAGRANT_DEFAULT_PROVIDER"]
      default = nil if default == ""
      default = default.to_sym if default

      # If we're forcing the default, just short-circuit and return
      # that (the default behavior)
      return default if default && opts[:force_default]

      # Determine the config to use to look for provider definitions. By
      # default it is the global but if we're targeting a specific machine,
      # then look there.
      root_config = vagrantfile.config
      if opts[:machine]
        machine_info = vagrantfile.machine_config(opts[:machine], nil, nil)
        root_config = machine_info[:config]
      end

      # Get the list of providers within our configuration and assign
      # a priority to each in the order they exist so that we try these first.
      config = {}
      root_config.vm.__providers.reverse.each_with_index do |key, idx|
        config[key] = idx
      end

      # Determine the max priority so that we can add the config priority
      # to that to make sure it is highest.
      max_priority = 0
      Vagrant.plugin("2").manager.providers.each do |key, data|
        priority = data[1][:priority]
        max_priority = priority if priority > max_priority
      end

      ordered = []
      Vagrant.plugin("2").manager.providers.each do |key, data|
        impl  = data[0]
        popts = data[1]

        # Skip excluded providers
        next if opts[:exclude] && opts[:exclude].include?(key)

        # Skip providers that can't be defaulted, unless they're in our
        # config, in which case someone made our decision for us.
        if !config.has_key?(key)
          next if popts.has_key?(:defaultable) && !popts[:defaultable]
        end

        # The priority is higher if it is in our config. Otherwise, it is
        # the priority it set PLUS the length of the config to make sure it
        # is never higher than the configuration keys.
        priority = popts[:priority]
        priority = config[key] + max_priority if config.has_key?(key)

        ordered << [priority, key, impl, popts]
      end

      # Order the providers by priority. Higher values are tried first.
      ordered = ordered.sort do |a, b|
        # If we see the default, then that one always wins
        next -1 if a[1] == default
        next 1  if b[1] == default

        b[0] <=> a[0]
      end

      # Find the matching implementation
      ordered.each do |_, key, impl, _|
        return key if impl.usable?(false)
      end

      # No providers available is a critical error for Vagrant.
      raise Errors::NoDefaultProvider
    end

    # Returns the collection of boxes for the environment.
    #
    # @return [BoxCollection]
    def boxes
      @_boxes ||= BoxCollection.new(
        boxes_path,
        hook: method(:hook),
        temp_dir_root: tmp_path)
    end

    # Returns the {Config::Loader} that can be used to load Vagrantflies
    # given the settings of this environment.
    #
    # @return [Config::Loader]
    def config_loader
      return @config_loader if @config_loader

      home_vagrantfile = nil
      root_vagrantfile = nil
      home_vagrantfile = find_vagrantfile(home_path) if home_path
      if root_path
        root_vagrantfile = find_vagrantfile(root_path, @vagrantfile_name)
      end

      @config_loader = Config::Loader.new(
        Config::VERSIONS, Config::VERSIONS_ORDER)
      @config_loader.set(:home, home_vagrantfile) if home_vagrantfile
      @config_loader.set(:root, root_vagrantfile) if root_vagrantfile
      @config_loader
    end

    # This defines a hook point where plugin action hooks that are registered
    # against the given name will be run in the context of this environment.
    #
    # @param [Symbol] name Name of the hook.
    # @param [Action::Runner] action_runner A custom action runner for running hooks.
    def hook(name, opts=nil)
      @logger.info("Running hook: #{name}")
      opts ||= {}
      opts[:callable] ||= Action::Builder.new
      opts[:runner] ||= action_runner
      opts[:action_name] = name
      opts[:env] = self
      opts.delete(:runner).run(opts.delete(:callable), opts)
    end

    # Returns the host object associated with this environment.
    #
    # @return [Class]
    def host
      return @host if defined?(@host)

      # Determine the host class to use. ":detect" is an old Vagrant config
      # that shouldn't be valid anymore, but we respect it here by assuming
      # its old behavior. No need to deprecate this because I thin it is
      # fairly harmless.
      host_klass = vagrantfile.config.vagrant.host
      host_klass = nil if host_klass == :detect

      begin
        @host = Host.new(
          host_klass,
          Vagrant.plugin("2").manager.hosts,
          Vagrant.plugin("2").manager.host_capabilities,
          self)
      rescue Errors::CapabilityHostNotDetected
        # If the auto-detect failed, then we create a brand new host
        # with no capabilities and use that. This should almost never happen
        # since Vagrant works on most host OS's now, so this is a "slow path"
        klass = Class.new(Vagrant.plugin("2", :host)) do
          def detect?(env); true; end
        end

        hosts     = { generic: [klass, nil] }
        host_caps = {}

        @host = Host.new(:generic, hosts, host_caps, self)
      rescue Errors::CapabilityHostExplicitNotDetected => e
        raise Errors::HostExplicitNotDetected, e.extra_data
      end
    end

    # This acquires a process-level lock with the given name.
    #
    # The lock file is held within the data directory of this environment,
    # so make sure that all environments that are locking are sharing
    # the same data directory.
    #
    # This will raise Errors::EnvironmentLockedError if the lock can't
    # be obtained.
    #
    # @param [String] name Name of the lock, since multiple locks can
    #   be held at one time.
    def lock(name="global", **opts)
      f = nil

      # If we don't have a block, then locking is useless, so ignore it
      return if !block_given?

      # This allows multiple locks in the same process to be nested
      return yield if @locks[name] || opts[:noop]

      # The path to this lock
      lock_path = data_dir.join("lock.#{name}.lock")

      @logger.debug("Attempting to acquire process-lock: #{name}")
      lock("dotlock", noop: name == "dotlock", retry: true) do
        f = File.open(lock_path, "w+")
      end

      # The file locking fails only if it returns "false." If it
      # succeeds it returns a 0, so we must explicitly check for
      # the proper error case.
      while f.flock(File::LOCK_EX | File::LOCK_NB) === false
        @logger.warn("Process-lock in use: #{name}")

        if !opts[:retry]
          raise Errors::EnvironmentLockedError,
            name: name
        end

        sleep 0.2
      end

      @logger.info("Acquired process lock: #{name}")

      result = nil
      begin
        # Mark that we have a lock
        @locks[name] = true

        result = yield
      ensure
        # We need to make sure that no matter what this is always
        # reset to false so we don't think we have a lock when we
        # actually don't.
        @locks.delete(name)
        @logger.info("Released process lock: #{name}")
      end

      # Clean up the lock file, this requires another lock
      if name != "dotlock"
        lock("dotlock", retry: true) do
          f.close
          File.delete(lock_path)
        end
      end

      # Return the result
      return result
    ensure
      begin
        f.close if f
      rescue IOError
      end
    end

    # This returns a machine with the proper provider for this environment.
    # The machine named by `name` must be in this environment.
    #
    # @param [Symbol] name Name of the machine (as configured in the
    #   Vagrantfile).
    # @param [Symbol] provider The provider that this machine should be
    #   backed by.
    # @param [Boolean] refresh If true, then if there is a cached version
    #   it is reloaded.
    # @return [Machine]
    def machine(name, provider, refresh=false)
      @logger.info("Getting machine: #{name} (#{provider})")

      # Compose the cache key of the name and provider, and return from
      # the cache if we have that.
      cache_key = [name, provider]
      @machines ||= {}
      if refresh
        @logger.info("Refreshing machine (busting cache): #{name} (#{provider})")
        @machines.delete(cache_key)
      end

      if @machines.has_key?(cache_key)
        @logger.info("Returning cached machine: #{name} (#{provider})")
        return @machines[cache_key]
      end

      @logger.info("Uncached load of machine.")

      # 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] = vagrantfile.machine(
        name, provider, boxes, machine_data_path, self)
    end

    # The {MachineIndex} to store information about the machines.
    #
    # @return [MachineIndex]
    def machine_index
      @machine_index ||= MachineIndex.new(@machine_index_dir)
    end

    # This returns a list of the configured machines for this environment.
    # Each of the names returned by this method is valid to be used with
    # the {#machine} method.
    #
    # @return [Array<Symbol>] Configured machine names.
    def machine_names
      vagrantfile.machine_names
    end

    # This returns the name of the machine that is the "primary." In the
    # case of  a single-machine environment, this is just the single machine
    # name. In the case of a multi-machine environment, then this can
    # potentially be nil if no primary machine is specified.
    #
    # @return [Symbol]
    def primary_machine_name
      vagrantfile.primary_machine_name
    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.
    #
    # @return [String]
    def root_path
      return @root_path if defined?(@root_path)

      root_finder = lambda do |path|
        # Note: To remain compatible with Ruby 1.8, we have to use
        # a `find` here instead of an `each`.
        vf = find_vagrantfile(path, @vagrantfile_name)
        return path if vf
        return nil if path.root? || !File.exist?(path)
        root_finder.call(path.parent)
      end

      @root_path = root_finder.call(cwd)
    end

    # Unload the environment, running completion hooks. The environment
    # should not be used after this (but CAN be, technically). It is
    # recommended to always immediately set the variable to `nil` after
    # running this so you can't accidentally run any more methods. Example:
    #
    #     env.unload
    #     env = nil
    #
    def unload
      hook(:environment_unload)
    end

    # Represents the default Vagrantfile, or the Vagrantfile that is
    # in the working directory or a parent of the working directory
    # of this environment.
    #
    # The existence of this function is primarily a convenience. There
    # is nothing stopping you from instantiating your own {Vagrantfile}
    # and loading machines in any way you see fit. Typical behavior of
    # Vagrant, however, loads this Vagrantfile.
    #
    # This Vagrantfile is comprised of two major sources: the Vagrantfile
    # in the user's home directory as well as the "root" Vagrantfile or
    # the Vagrantfile in the working directory (or parent).
    #
    # @return [Vagrantfile]
    def vagrantfile
      @vagrantfile ||= Vagrantfile.new(config_loader, [:home, :root])
    end

    #---------------------------------------------------------------
    # Load Methods
    #---------------------------------------------------------------

    # This sets the `@home_path` variable properly.
    #
    # @return [Pathname]
    def setup_home_path
      @logger.info("Home path: #{@home_path}")

      # Setup the list of child directories that need to be created if they
      # don't already exist.
      dirs    = [
        @home_path,
        @home_path.join("rgloader"),
        @boxes_path,
        @data_dir,
        @gems_path,
        @tmp_path,
        @machine_index_dir,
      ]

      # Go through each required directory, creating it if it doesn't exist
      dirs.each do |dir|
        next if File.directory?(dir)

        begin
          @logger.info("Creating: #{dir}")
          FileUtils.mkdir_p(dir)
        rescue Errno::EACCES
          raise Errors::HomeDirectoryNotAccessible, home_path: @home_path.to_s
        end
      end

      # Attempt to write into the home directory to verify we can
      begin
        # Append a random suffix to avoid race conditions if Vagrant
        # is running in parallel with other Vagrant processes.
        suffix = (0...32).map { (65 + rand(26)).chr }.join
        path   = @home_path.join("perm_test_#{suffix}")
        path.open("w") do |f|
          f.write("hello")
        end
        path.unlink
      rescue Errno::EACCES
        raise Errors::HomeDirectoryNotAccessible, home_path: @home_path.to_s
      end

      # Create the version file that we use to track the structure of
      # the home directory. If we have an old version, we need to explicitly
      # upgrade it. Otherwise, we just mark that its the current version.
      version_file = @home_path.join("setup_version")
      if version_file.file?
        version = version_file.read.chomp
        if version > CURRENT_SETUP_VERSION
          raise Errors::HomeDirectoryLaterVersion
        end

        case version
        when CURRENT_SETUP_VERSION
          # We're already good, at the latest version.
        when "1.1"
          # We need to update our directory structure
          upgrade_home_path_v1_1

          # Delete the version file so we put our latest version in
          version_file.delete
        else
          raise Errors::HomeDirectoryUnknownVersion,
            path: @home_path.to_s,
            version: version
        end
      end

      if !version_file.file?
        @logger.debug(
          "Creating home directory version file: #{CURRENT_SETUP_VERSION}")
        version_file.open("w") do |f|
          f.write(CURRENT_SETUP_VERSION)
        end
      end

      # Create the rgloader/loader file so we can use encoded files.
      loader_file = @home_path.join("rgloader", "loader.rb")
      if !loader_file.file?
        source_loader = Vagrant.source_root.join("templates/rgloader.rb")
        FileUtils.cp(source_loader.to_s, loader_file.to_s)
      end
    end

    # This creates the local data directory and show an error if it
    # couldn't properly be created.
    def setup_local_data_path
      if @local_data_path.nil?
        @logger.warn("No local data path is set. Local data cannot be stored.")
        return
      end

      @logger.info("Local data path: #{@local_data_path}")

      # If the local data path is a file, then we are probably seeing an
      # old (V1) "dotfile." In this case, we upgrade it. The upgrade process
      # will remove the old data file if it is successful.
      if @local_data_path.file?
        upgrade_v1_dotfile(@local_data_path)
      end

      begin
        @logger.debug("Creating: #{@local_data_path}")
        FileUtils.mkdir_p(@local_data_path)
      rescue Errno::EACCES
        raise Errors::LocalDataDirectoryNotAccessible,
          local_data_path: @local_data_path.to_s
      end
    end

    protected

    # This method copies the private key into the home directory if it
    # doesn't already exist.
    #
    # This must be done because `ssh` requires that the key is chmod
    # 0600, but if Vagrant is installed as a separate user, then the
    # effective uid won't be able to read the key. So the key is copied
    # to the home directory and chmod 0600.
    def copy_insecure_private_key
      if !@default_private_key_path.exist?
        @logger.info("Copying private key to home directory")

        source      = File.expand_path("keys/vagrant", Vagrant.source_root)
        destination = @default_private_key_path

        begin
          FileUtils.cp(source, destination)
        rescue Errno::EACCES
          raise Errors::CopyPrivateKeyFailed,
            source: source,
            destination: destination
        end
      end

      if !Util::Platform.windows?
        # On Windows, permissions don't matter as much, so don't worry
        # about doing chmod.
        if Util::FileMode.from_octal(@default_private_key_path.stat.mode) != "600"
          @logger.info("Changing permissions on private key to 0600")
          @default_private_key_path.chmod(0600)
        end
      end
    end

    # Finds the Vagrantfile in the given directory.
    #
    # @param [Pathname] path Path to search in.
    # @return [Pathname]
    def find_vagrantfile(search_path, filenames=nil)
      filenames ||= ["Vagrantfile", "vagrantfile"]
      filenames.each do |vagrantfile|
        current_path = search_path.join(vagrantfile)
        return current_path if current_path.file?
      end

      nil
    end

    # This upgrades a home directory that was in the v1.1 format to the
    # v1.5 format. It will raise exceptions if anything fails.
    def upgrade_home_path_v1_1
      @ui.ask(I18n.t("vagrant.upgrading_home_path_v1_5"))
      collection = BoxCollection.new(
        @home_path.join("boxes"), temp_dir_root: tmp_path)
      collection.upgrade_v1_1_v1_5
    end

    # This upgrades a Vagrant 1.0.x "dotfile" to the new V2 format.
    #
    # This is a destructive process. Once the upgrade is complete, the
    # old dotfile is removed, and the environment becomes incompatible for
    # Vagrant 1.0 environments.
    #
    # @param [Pathname] path The path to the dotfile
    def upgrade_v1_dotfile(path)
      @logger.info("Upgrading V1 dotfile to V2 directory structure...")

      # First, verify the file isn't empty. If it is an empty file, we
      # just delete it and go on with life.
      contents = path.read.strip
      if contents.strip == ""
        @logger.info("V1 dotfile was empty. Removing and moving on.")
        path.delete
        return
      end

      # Otherwise, verify there is valid JSON in here since a Vagrant
      # environment would always ensure valid JSON. This is a sanity check
      # to make sure we don't nuke a dotfile that is not ours...
      @logger.debug("Attempting to parse JSON of V1 file")
      json_data = nil
      begin
        json_data = JSON.parse(contents)
        @logger.debug("JSON parsed successfully. Things are okay.")
      rescue JSON::ParserError
        # The file could've been tampered with since Vagrant 1.0.x is
        # supposed to ensure that the contents are valid JSON. Show an error.
        raise Errors::DotfileUpgradeJSONError,
          state_file: path.to_s
      end

      # Alright, let's upgrade this guy to the new structure. Start by
      # backing up the old dotfile.
      backup_file = path.dirname.join(".vagrant.v1.#{Time.now.to_i}")
      @logger.info("Renaming old dotfile to: #{backup_file}")
      path.rename(backup_file)

      # Now, we create the actual local data directory. This should succeed
      # this time since we renamed the old conflicting V1.
      setup_local_data_path

      if json_data["active"]
        @logger.debug("Upgrading to V2 style for each active VM")
        json_data["active"].each do |name, id|
          @logger.info("Upgrading dotfile: #{name} (#{id})")

          # Create the machine configuration directory
          directory = @local_data_path.join("machines/#{name}/virtualbox")
          FileUtils.mkdir_p(directory)

          # Write the ID file
          directory.join("id").open("w+") do |f|
            f.write(id)
          end
        end
      end

      # Upgrade complete! Let the user know
      @ui.info(I18n.t("vagrant.general.upgraded_v1_dotfile",
                      backup_path: backup_file.to_s))
    end
  end
end