Class TaskJuggler::Daemon
In: lib/taskjuggler/daemon/Daemon.rb
Parent: Object

This class provides the basic functionality to turn the current process into a background process (daemon). To use it, derive you main class from this class and call the start() method.

Methods

new   start   stop  

Attributes

daemonize  [RW] 
log  [R] 

Public Class methods

new()

[Source]

# File lib/taskjuggler/daemon/Daemon.rb, line 26
    def initialize
      # You can set this flag to false to prevent the program from
      # disconnecting from the current terminal. This is useful for debugging
      # purposes.
      @daemonize = true
      @log = LogFile.instance
    end

Public Instance methods

start()

Call this method to turn the process into a background process.

[Source]

# File lib/taskjuggler/daemon/Daemon.rb, line 35
    def start
      return unless @daemonize

      # Fork and have the parent exit
      if (pid = fork) == -1
        @log.fatal('First fork failed')
      elsif !pid.nil?
        # This is the parent. We can exit now.
        @log.debug("Forked a child process with PID #{pid}")
        exit! 0
      end

      # Create a new session
      Process.setsid
      # Fork again to make sure we lose the controlling terminal
      if (pid = fork) == -1
        @log.fatal('Second fork failed')
      elsif !pid.nil?
        # This is the parent. We can exit now.
        @log.debug("Forked a child process with PID #{pid}")
        exit! 0
      end

      @pid = Process.pid

      # Change current working directory to the file system root
      Dir.chdir '/'
      # Make sure we can create files with any permission
      File.umask 0

      # We no longer have a controlling terminal, so these are useless.
      $stdin.reopen('/dev/null')
      $stdout.reopen('/dev/null', 'a')
      $stderr.reopen($stdout)

      @log.info("The process is running as daemon now with PID #{@pid}")
      0
    end
stop()

This method may provide some cleanup functionality in the future. You better call it before you exit.

[Source]

# File lib/taskjuggler/daemon/Daemon.rb, line 76
    def stop
    end

[Validate]