restart chef runs and continue from where it was

_usage.rb

before_restart "stage 1" do
  puts "hi we are executing stage 1..."
  puts "stage 1 done"
end

before_restart "stage 2" do
  puts "hi we are executing stage 2..."
  puts "stage 2 done"
end

before_restart "stage 3" do
  puts "hi we are executing stage 3..."
  puts "stage 3 done"
end

puts "continue"

chef_restart.rb

def cookbook_name
  "cookbook"
end
def recipe_name
  "recipe"
end

module Chef
  module Restart
    def before_restart(name=nil,&blk)
      Chef::Restart.before_restart(name,&blk)
    end

    private
    def self.moduleinit
      @run = {}
      @counter = {}
    end
    moduleinit

    def self.before_restart(name=nil,&blk)
      @name = "chef_run_#{cookbook_name}_#{recipe_name}"
      @run[@name] ||= Run.new(@name)

      incr_count()
      if env == count.to_s
        yield
        incr_env()
        @run[@name].restart!
      end
    end

    def self.incr_count
      @counter[@name] ||= 0
      @counter[@name]  += 1
    end

    def self.count
      @counter[@name]
    end

    def self.incr_env
      ENV[@name] ||= "0"
      ENV[@name] = (ENV[@name].to_i+1).to_s
    end
    
    def self.env
      ENV[@name] ||= "1"
    end
    
    class Run
      def initialize(name)
        @name = name
      end
      
      def restart!(msg="Restarting #{File.basename $0}, #{@name}...")
        if fork # we're the parent
          puts msg
          # Chef::Log.info(msg)
          sleep unspecified_shutdown_time = 2
          exit 0
        else   
          # in child
          sleep 1 until(Process.ppid() == 1)
          exec($0+" "+$*.join(" "))
        end
      end
    end
  end
end

class Object
  include Chef::Restart
end

restart_example_with_case_statement.rb

def restart(recipe,&blk)
  if fork # we're the parent
    puts "Restarting!"
    sleep unspecified_shutdown_time = 2
    exit 0
  else   
    # in child
    sleep 1 until(Process.ppid() == 1)
    ENV["chef_run_#{recipe}"] = (ENV["chef_run_#{recipe}"].to_i+1).to_s
    exec($0+" "+$*.join(" "))
  end
end

puts $0+" "+$*.inspect
recipe="recipe"
case ENV["chef_run_#{recipe}"] ||= "1"

when "1"
  puts "first execution run"
  restart recipe
  
when "2"
  puts "second execution run"
  restart recipe

when "3"
  puts "third execution run"
  restart recipe
end

puts "continue"