demo_daemon.rb

LOG_FILE = 'C:\\tmp\\win32_daemon_test.log'

begin  
  require 'rubygems'
  require 'win32/daemon'
  include Win32

  class DemoDaemon < Daemon
    # This method fires off before the +service_main+ mainloop is entered.
    # Any pre-setup code you need to run before your service's mainloop
    # starts should be put here. Otherwise the service might fail with a
    # timeout error when you try to start it.
    #
    def service_init
      10.times{ |i|
        File.open(LOG_FILE , 'a'){ |f| f.puts("#{i}") }
        sleep 1
      }
    end
      
    # This is the daemon's mainloop. In other words, whatever runs here
    # is the code that runs while your service is running. Note that the
    # loop is not implicit.
    #
    # You must setup a loop as I've done here with the 'while running?'
    # code, or setup your own loop. Otherwise your service will exit and
    # won't be especially useful.
    #
    # In this particular case, I've setup a loop to append a short message
    # and timestamp to a file on your C: drive every 20 seconds. Be sure
    # to stop the service when you're done!
    #
    def service_main(*args)
      msg = 'service_main entered at: ' + Time.now.to_s

      File.open(LOG_FILE, 'a'){ |f|
        f.puts msg
        f.puts "Args: " + args.join(',')
      }

      # While we're in here the daemon is running.
      while running?
        if state == RUNNING
          sleep 20 
          msg = 'Service is running as of: ' + Time.now.to_s
          File.open(LOG_FILE, 'a'){ |f| f.puts msg }
        else # PAUSED or IDLE
          sleep 0.5
        end
      end

      # We've left the loop, the daemon is about to exit.
      
      File.open(LOG_FILE, 'a'){ |f| f.puts "STATE: #{state}" }
      
      msg = 'service_main left at: ' + Time.now.to_s

      File.open(LOG_FILE, 'a'){ |f| f.puts msg }
    end
   
    # This event triggers when the service receives a signal to stop. I've
    # added an explicit "exit!" here to ensure that the Ruby interpreter exits
    # properly. I use 'exit!' instead of 'exit' because otherwise Ruby will
    # raise a SystemExitError, which I don't want.
    #
    def service_stop
      msg = 'Received stop signal at: ' + Time.now.to_s
      File.open(LOG_FILE, 'a'){ |f| f.puts msg }
      exit!
    end
      
    # This event triggers when the service receives a signal to pause. 
    #
    def service_pause
      msg = 'Received pause signal at: ' + Time.now.to_s
      File.open(LOG_FILE, 'a'){ |f| f.puts msg }
    end
      
    # This event triggers when the service receives a signal to resume
    # from a paused state.
    #
    def service_resume
      msg = 'Received resume signal at: ' + Time.now.to_s
      File.open(LOG_FILE, 'a'){ |f| f.puts msg }
    end
  end

  # Create an instance of the Daemon and put it into a loop. I borrowed the
  # method name 'mainloop' from Tk, btw.
  #
  DemoDaemon.mainloop
rescue Exception => err
  File.open(LOG_FILE, 'a'){ |fh| fh.puts "Daemon failure: #{err}" }
  raise
end