Method: Daemonize.call_as_daemon

Defined in:
lib/daemons/daemonize.rb

.call_as_daemon(block, logfile_name = nil, app_name = nil) ⇒ Object

Call a given block as a daemon



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# File 'lib/daemons/daemonize.rb', line 41

def call_as_daemon(block, logfile_name = nil, app_name = nil)
  # we use a pipe to return the PID of the daemon
  rd, wr = IO.pipe

  if tmppid = safefork
    # in the parent

    wr.close
    pid = rd.read.to_i
    rd.close

    Process.waitpid(tmppid)

    return pid
  else
    # in the child

    rd.close

    # Detach from the controlling terminal
    unless Process.setsid
      fail Daemons.RuntimeException.new('cannot detach from controlling terminal')
    end

    # Prevent the possibility of acquiring a controlling terminal
    trap 'SIGHUP', 'IGNORE'
    exit if pid = safefork

    wr.write Process.pid
    wr.close

    $0 = app_name if app_name

    # Release old working directory
    Dir.chdir '/'

    close_io

    redirect_io(logfile_name)

    # Split rand streams between spawning and daemonized process
    srand

    block.call

    exit
  end
end