Module: Daemonizer::Daemonize

Defined in:
lib/daemonizer/daemonize.rb

Class Method Summary collapse

Class Method Details

.check_pid(pid_file) ⇒ Object 



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# File 'lib/daemonizer/daemonize.rb', line 11

def self.check_pid(pid_file)
  pid = read_pid(pid_file)
  return false if pid.zero?
  if defined?(::JRuby)
    system "kill -0 #{pid} &> /dev/null"
    return $? == 0
  else
    Process.kill(0, pid)
  end
  true
rescue Errno::ESRCH, Errno::ECHILD, Errno::EPERM
  false
end

.create_pid(pid_file) ⇒ Object 



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# File 'lib/daemonizer/daemonize.rb', line 25

def self.create_pid(pid_file)
  if File.exist?(pid_file)
    puts "Pid file #{pid_file} exists! Checking the process..."
    if check_pid(pid_file)
      puts "Can't create new pid file because another process is runnig!"
      return false
    end
    puts "Stale pid file! Removing..."
    File.delete(pid_file)
  end

  File.open(pid_file, 'w') do |f|
    f.puts(Process.pid)
  end

  return true
end

.daemonize(app_name) ⇒ Object 



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# File 'lib/daemonizer/daemonize.rb', line 43

def self.daemonize(app_name)
  if defined?(::JRuby)
    puts "WARNING: daemonize method is not implemented for JRuby (yet), please consider using nohup."
    return
  end

  fork && exit # Fork and exit from the parent

  STDIN.reopen '/dev/null'
  STDOUT.reopen '/dev/null', 'a'
  STDERR.reopen STDOUT
  
  # Detach from the controlling terminal
  unless sess_id = Process.setsid
    raise 'cannot detach from controlling terminal'
  end

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

  $0 = app_name if app_name
  
  File.umask(0000) # Insure sensible umask

  return sess_id
end

.read_pid(pid_file) ⇒ Object 



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# File 'lib/daemonizer/daemonize.rb', line 3

def self.read_pid(pid_file)
  File.open(pid_file) do |f|
    f.gets.to_i
  end
rescue Errno::ENOENT
  0
end