Class: Win32::Daemon

Inherits:

Object

Object
Win32::Daemon

show all

Extended by:: Windows::Functions, Windows::Structs

Includes:: Windows::Constants, Windows::Functions, Windows::Structs

Defined in:: lib/win32/daemon.rb

Overview

The Daemon class

Constant Summary collapse

VERSION = The version of this library

'0.8.0'

Constants included from Windows::Constants

Class Method Summary collapse

.mainloop ⇒ Object

This is a shortcut for Daemon.new + Daemon#mainloop.

Instance Method Summary collapse

#mainloop ⇒ Object

This is the method that actually puts your code into a loop and allows it to run as a service.
#running? ⇒ Boolean

Returns whether or not the service is in a running state, i.e.
#state ⇒ Object

Returns the state of the service (as an constant integer) which can be any of the service status constants, e.g.

Class Method Details

.mainloop ⇒ `Object`

This is a shortcut for Daemon.new + Daemon#mainloop.



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# File 'lib/win32/daemon.rb', line 201

def self.mainloop
  self.new.mainloop
end

Instance Method Details

#mainloop ⇒ `Object`

This is the method that actually puts your code into a loop and allows it to run as a service. The code that is actually run while in the mainloop is what you defined in your own Daemon#service_main method.

# File 'lib/win32/daemon.rb', line 209

def mainloop
  @@waiting_control_code = IDLE_CONTROL_CODE
  @@dwServiceState = 0

  # Redirect STDIN, STDOUT and STDERR to the NUL device if they're still
  # associated with a tty. This helps newbs avoid Errno::EBADF errors.
  STDIN.reopen('NUL') if STDIN.isatty
  STDOUT.reopen('NUL') if STDOUT.isatty
  STDERR.reopen('NUL') if STDERR.isatty

  # Calling init here so that init failures never even tries to start the
  # service. Of course that means that init methods must be very quick
  # because the SCM will be receiving no START_PENDING messages while
  # init's running.
  #
  # TODO: Fix?
  service_init() if respond_to?('service_init')

  # Create the event to signal the service to start.
  @@hStartEvent = CreateEvent(nil, true, false, nil)

  if @@hStartEvent == 0
    raise SystemCallError.new('CreateEvent', FFI.errno)
  end

  # Create the event to signal the service to stop.
  @@hStopEvent = CreateEvent(nil, true, false, nil)

  if @@hStopEvent == 0
    raise SystemCallError.new('CreateEvent', FFI.errno)
  end

  # Create the event to signal the service that stop has completed
  @@hStopCompletedEvent = CreateEvent(nil, true, false, nil)

  if @@hStopCompletedEvent == 0
    raise SystemCallError.new('CreateEvent', FFI.errno)
  end

  hThread = CreateThread(nil, 0, ThreadProc, nil, 0, nil)

  if hThread == 0
    raise SystemCallError.new('CreateThread', FFI.errno)
  end

  events = FFI::MemoryPointer.new(:pointer, FFI::Pointer.size*2)
  events.put_pointer(0, FFI::Pointer.new(hThread))
  events.put_pointer(FFI::Pointer.size, FFI::Pointer.new(@@hStartEvent))

  while ((index = WaitForMultipleObjects(2, events, false, 1000)) == WAIT_TIMEOUT) do
  end

  if index == WAIT_FAILED
    raise SystemCallError.new('WaitForMultipleObjects', FFI.errno)
  end

  # The thread exited, so the show is off.
  if index == WAIT_OBJECT_0
    raise "Service_Main thread exited abnormally"
  end

  thr = Thread.new do
    while(WaitForSingleObject(@@hStopEvent, 10) == WAIT_TIMEOUT)
      # Check to see if anything interesting has been signaled
      case @@waiting_control_code
        when SERVICE_CONTROL_PAUSE
          service_pause() if respond_to?('service_pause')
        when SERVICE_CONTROL_CONTINUE
          service_resume() if respond_to?('service_resume')
        when SERVICE_CONTROL_INTERROGATE
          service_interrogate() if respond_to?('service_interrogate')
        when SERVICE_CONTROL_SHUTDOWN
          service_shutdown() if respond_to?('service_shutdown')
        when SERVICE_CONTROL_PARAMCHANGE
          service_paramchange() if respond_to?('service_paramchange')
        when SERVICE_CONTROL_NETBINDADD
          service_netbindadd() if respond_to?('service_netbindadd')
        when SERVICE_CONTROL_NETBINDREMOVE
          service_netbindremove() if respond_to?('service_netbindremove')
        when SERVICE_CONTROL_NETBINDENABLE
          service_netbindenable() if respond_to?('service_netbindenable')
        when SERVICE_CONTROL_NETBINDDISABLE
          service_netbinddisable() if respond_to?('service_netbinddisable')
      end
      @@waiting_control_code = IDLE_CONTROL_CODE
    end

    service_stop() if respond_to?('service_stop')
  end

  if respond_to?('service_main')
    service_main(*@@Argv)
  end

  thr.join
end

#running? ⇒ `Boolean`

Returns whether or not the service is in a running state, i.e. the service status is either RUNNING, PAUSED or IDLE.

This is typically used within your service_main method to setup the main loop. For example:

class MyDaemon < Daemon
   def service_main
      while running?
         # Your main loop here
      end
   end
end

Returns:

(Boolean)



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# File 'lib/win32/daemon.rb', line 341

def running?
  [SERVICE_RUNNING, SERVICE_PAUSED, 0].include?(@@dwServiceState)
end

#state ⇒ `Object`

Returns the state of the service (as an constant integer) which can be any of the service status constants, e.g. RUNNING, PAUSED, etc.

This method is typically used within your service_main method to setup the loop. For example:

class MyDaemon < Daemon
  def service_main
    while state == RUNNING || state == PAUSED || state == IDLE
      # Your main loop here
    end
  end
end

See the Daemon#running? method for an abstraction of the above code.



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# File 'lib/win32/daemon.rb', line 322

def state
  @@dwServiceState
end