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, status.



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# File 'lib/rexec/daemon/controller.rb', line 34

def self.daemonize(daemon)
  case ARGV.shift
  when 'start'
    start(daemon)
    status(daemon)
  when 'stop'
    stop(daemon)
    status(daemon)
    ProcessFile.cleanup(daemon)
  when 'restart'
    stop(daemon)
    ProcessFile.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 57

def self.start(daemon)
  puts "Starting daemon...".color(:blue)

  case ProcessFile.status(daemon)
  when :running
    $stderr.puts "Daemon already running!".color(:blue)
    return
  when :stopped
    # We are good to go...
  else
    $stderr.puts "Daemon in unknown state! Will clear previous state and continue.".color(:red)
    status(daemon)
    ProcessFile.clear(daemon)
  end

  daemon.prefork
  daemon.mark_log

  fork do
    Process.setsid
    exit if fork

    ProcessFile.store(daemon, Process.pid)

    File.umask 0000
    Dir.chdir daemon.working_directory

    $stdin.reopen "/dev/null"
    $stdout.reopen daemon.log_file_path, "a"
    $stdout.sync = true
    
    $stderr.reopen $stdout
    $stderr.sync = true

    begin
      error = nil
      
      main = Thread.new do
        begin
          daemon.run
        rescue
          error = $!
        end
      end

      trap("INT") do
        begin
          daemon.shutdown
          main.exit
        rescue
          error = $!
        end
      end

      trap("TERM") do
        exit!
      end

      main.join

      raise error if error
    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
    ensure
      $stderr.puts "=== Daemon Stopping @ #{Time.now.to_s} ==="
      $stderr.flush
    end
  end

  puts "Waiting for daemon to start...".color(:blue)
  sleep 0.1
  timer = TIMEOUT
  pid = ProcessFile.recall(daemon)

  while pid == nil and timer > 0
    # Wait a moment for the forking to finish...
    puts "Waiting for daemon to start (#{timer}/#{TIMEOUT})".color(:blue)
    sleep 1

    # If the daemon has crashed, it is never going to start...
    break if daemon.crashed?

    pid = ProcessFile.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 150

def self.status(daemon)
  case ProcessFile.status(daemon)
  when :running
    puts "Daemon status: running pid=#{ProcessFile.recall(daemon)}".color(:green)
  when :unknown
    if daemon.crashed?
      puts "Daemon status: crashed".color(:red)

      $stdout.flush
      $stderr.puts "Dumping daemon crash log:".color(:red)
      daemon.tail_log($stderr)
    else
      puts "Daemon status: unknown".color(:red)
    end
  when :stopped
    puts "Daemon status: stopped".color(:blue)
  end
end

.stop(daemon) ⇒ Object

Stops the daemon process.



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# File 'lib/rexec/daemon/controller.rb', line 170

def self.stop(daemon)
  puts "Stopping daemon...".color(:blue)

  # Check if the pid file exists...
  unless File.file?(daemon.process_file_path)
    puts "Pid file not found. Is the daemon running?".color(:red)
    return
  end

  pid = ProcessFile.recall(daemon)

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

  pid = ProcessFile.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 ProcessFile.running(daemon) and attempts > 0
    sig = (attempts < 2) ? "KILL" : "TERM"

    puts "Sending #{sig} to pid #{pid}...".color(:red)
    Process.kill(sig, pid)

    sleep 1
    attempts -= 1
  end

  # If after doing our best the daemon is still running (pretty odd)...
  if ProcessFile.running(daemon)
    puts "Daemon appears to be still running!".color(:red)
    return
  end

  # Otherwise the daemon has been stopped.
  ProcessFile.clear(daemon)
end