Module: RExec::Daemon::Controller

Defined in:
lib/rexec/daemon/controller.rb

Overview

This module contains functionality related to starting and stopping the daemon, and code for processing command line input.

Class Method Summary collapse

Class Method Details

.daemonize(daemon) ⇒ Object

This function is called from the daemon executable. It processes ARGV and checks whether the user is asking for start, stop, restart or status.



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# File 'lib/rexec/daemon/controller.rb', line 28

def self.daemonize(daemon)
  #puts "Running in #{WorkingDirectory}, logs in #{LogDirectory}"
  case !ARGV.empty? && ARGV[0]
  when 'start'
    start(daemon)
    status(daemon)
  when 'stop'
    stop(daemon)
    status(daemon)
    PidFile.cleanup(daemon)
  when 'restart'
    stop(daemon)
    PidFile.cleanup(daemon)
    start(daemon)
    status(daemon)
  when 'status'
    status(daemon)
  else
    puts "Invalid command. Please specify start, restart, stop or status."
    exit
  end
end

.start(daemon) ⇒ Object

This function starts the supplied daemon



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# File 'lib/rexec/daemon/controller.rb', line 52

def self.start(daemon)
  puts "Starting daemon..."
  
  case PidFile.status(daemon)
  when :running
    $stderr.puts "Daemon already running!"
    return
  when :stopped
    # We are good to go...
  else
    $stderr.puts "Daemon in unknown state! Will clear previous state and continue."
    status(daemon)
    PidFile.clear(daemon)
  end

  daemon.prefork
  daemon.mark_err_log

  fork do
    Process.setsid
    exit if fork

    PidFile.store(daemon, Process.pid)

    File.umask 0000
    Dir.chdir daemon.working_directory

    $stdin.reopen "/dev/null"
    $stdout.reopen daemon.log_fn, "a"
    $stderr.reopen daemon.err_fn, "a"

    main = Thread.new do
      begin
        daemon.run
      rescue
        $stderr.puts "=== Daemon Exception Backtrace @ #{Time.now.to_s} ==="
        $stderr.puts "#{$!.class}: #{$!.message}"
        $!.backtrace.each { |at| $stderr.puts at }
        $stderr.puts "=== Daemon Crashed ==="
        
        $stderr.flush
      end
    end

					trap("INT") do
daemon.shutdown
main.exit
					end

    trap("TERM") do
      exit!
    end

    main.join
  end

  puts "Waiting for daemon to start..."
  sleep 0.1
  timer = TIMEOUT
  pid = PidFile.recall(daemon)
  
  while pid == nil and timer > 0
    # Wait a moment for the forking to finish...
    puts "Waiting for daemon to start (#{timer}/#{TIMEOUT})"
    sleep 1
    
    # If the daemon has crashed, it is never going to start...
    break if daemon.crashed?
    
    pid = PidFile.recall(daemon)
    
    timer -= 1
  end
end

.status(daemon) ⇒ Object

Prints out the status of the daemon



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# File 'lib/rexec/daemon/controller.rb', line 128

def self.status(daemon)
  case PidFile.status(daemon)
  when :running
    puts "Daemon status: running pid=#{PidFile.recall(daemon)}"
  when :unknown
    if daemon.crashed?
      puts "Daemon status: crashed"
      
      $stdout.flush
      daemon.tail_err_log($stderr)
    else
      puts "Daemon status: unknown"
    end
  when :stopped
    puts "Daemon status: stopped"
  end
end

.stop(daemon) ⇒ Object

Stops the daemon process.



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# File 'lib/rexec/daemon/controller.rb', line 147

def self.stop(daemon)
  puts "Stopping daemon..."
  
  # Check if the pid file exists...
  if !File.file?(daemon.pid_fn)
    puts "Pid file not found. Is the daemon running?"
    return
  end

  pid = PidFile.recall(daemon)

  # Check if the daemon is already stopped...
  unless PidFile.running(daemon)
    puts "Pid #{pid} is not running. Has daemon crashed?"
    return
  end

  pid = PidFile.recall(daemon)
  Process.kill("INT", pid)
  sleep 0.1
  
  # Kill/Term loop - if the daemon didn't die easily, shoot
  # it a few more times.
  attempts = 5
  while PidFile.running(daemon) and attempts > 0
    sig = (attempts < 2) ? "KILL" : "TERM"
    
    puts "Sending #{sig} to pid #{pid}..."
    Process.kill(sig, pid)
    
    sleep 1 unless first
    attempts -= 1
  end
  
  # If after doing our best the daemon is still running (pretty odd)...
  if PidFile.running(daemon)
    puts "Daemon appears to be still running!"
    return
  end
  
  # Otherwise the daemon has been stopped.
  PidFile.clear(daemon)
end