vagrant snapshot management command for one vm.

vagrant-snapshot.rb

## place this file to same directory of `Vagrantfile' then simply require "snap.rb" in Vagrantfile

module Snap
  module VBox
    class SnapShot
      require "forwardable"
      extend Forwardable
      def_delegators :@snap, :name, :uuid, :time_stamp
      @@snaps = []
      class << self
        def is_endnode?() @@current.uuid == @@snaps.last.uuid end

        def snaps() @@snaps end 

        def parse_tree(vmname)
          vm = VirtualBox::VM.find( vmname )
          @@current = vm.current_snapshot
          return unless @@current
          new(vm.root_snapshot).walk
        end
      end

      def initialize(snap)
        @snap = snap
        self.class.snaps << self
      end
      def current?
        snap.uuid == @@current.uuid
      end
      def register
      end
      attr_reader :snap

      def have_child?
        ! @snap.children.empty?
      end

      def first_child
        snap.children.first
      end

      def walk
        if have_child?
          s = self.class.new first_child
          s.walk
        end
      end
    end
  end

  class Command < Vagrant::Command::GroupBase
    register "snap","Manages a snap"

    no_tasks {
      def vmname
        @vagrant_env ||= Vagrant::Environment.new
        @instance_name ||= "#{@vagrant_env.vms[:default].vm.name}"
        @instance_name
      end
    }

    desc "list", "list snapshot"
    def list
      format = " %s %-20s %s"
      VBox::SnapShot.parse_tree( vmname )
      result = VBox::SnapShot.snaps.map do |s|
        cur_mark = s.current? ? "*" : " "
        format % [ cur_mark, s.time_stamp.strftime("%Y%m%d-%H:%M:%S"), s.name ]
      end
      puts result
    end

    desc "go [SNAPNAME]", "go to specified snapshot"
    def go(snapshot_name)
      system "VBoxManage controlvm #{vmname} poweroff"
      system "VBoxManage snapshot  #{vmname} restore #{snapshot_name}"
      system "VBoxManage startvm   #{vmname} --type headless"
    end

    desc "back", "back to current snapshot"
    def back
      system "VBoxManage controlvm #{vmname} poweroff"
      system "VBoxManage snapshot  #{vmname} restorecurrent"
      system "VBoxManage startvm   #{vmname} --type headless"
    end

    desc "take", "take snapshot"
    def take
      VBox::SnapShot.parse_tree( vmname )
      last = VBox::SnapShot.snaps.last
      new_name = last ? last.name.succ : vmname + "-01"
      # new_name = last.name.succ
      if not last or VBox::SnapShot.is_endnode?
        system "VBoxManage snapshot #{vmname} take #{new_name} --pause"
      else
        puts "Can not create"
      end
    end

    desc "delete", "delete snapshot"
    def delete(snapshot_name)
      system "VBoxManage snapshot #{vmname} delete #{snapshot_name}"
    end
  end
end