Module: Kernel

Defined in:
lib/epitools/its.rb,
lib/epitools/daemonize.rb

Instance Method Summary collapse

Instance Method Details

#daemonize(chdir = nil, &on_sighup) ⇒ Object

This method causes the current running process to become a daemon All further printing is relied to the error.log FIXME doesn’t belong into Butler::Bot, rather into botcontrol



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# File 'lib/epitools/daemonize.rb', line 5

def daemonize(chdir=nil, &on_sighup)
  srand # Split rand streams between spawning and daemonized process
  safe_fork and exit # Fork and exit from the parent

  # Detach from the controlling terminal
  raise "Can't detach from controlling terminal" unless sess_id = Process.setsid

  # Prevent the possibility of acquiring a controlling terminal
  trap('SIGHUP', 'IGNORE')
  exit if safe_fork

  # In daemon mode, a SIGHUP means termination
  trap('SIGHUP', &on_sighup)

  # We can't get the originally controlling terminals stdout/stdin anymore
  STDIN.reopen("/dev/null")
  STDOUT.reopen("/dev/null", "a")
  STDERR.reopen(STDOUT)
  
  Dir.chdir(chdir) if chdir
  File.umask 0033 # FIXME ask somebody knowledgable about a sensible value

  sess_id
end

#safe_fork(delay = 5) ⇒ Object

Try to fork if at all possible retrying every delay sec (5s default) if the maximum process limit for the system has been reached



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# File 'lib/epitools/daemonize.rb', line 32

def safe_fork(delay=5)
  fork
rescue Errno::EWOULDBLOCK
  sleep(delay)
  retry
end