a quick and dirty jruby daemon based on basic_daemon

daemon.rb

#!/usr/bin/env jruby
#
#

require 'rubygems'
require 'spoon'

EXEC      = '/tmp/exec.rb'
PID_PATH  = '/tmp/exec.pid'
WORK_PATH = '/tmp/'

def create_pid(pid)
  begin
    open(PID_PATH, 'w') do |f|
      f.puts pid
    end
  rescue => e
    STDERR.puts "Error: Unable to open #{PID_PATH} for writing:\n\t" +
        "(#{e.class}) #{e.message}"
    exit!
  end
end

def get_pid
  pid = false
  begin
    open(PID_PATH, 'r') do |f|
      pid = f.readline
      pid = pid.to_s.gsub(/[^0-9]/,'')
    end
  rescue => e
    STDERR.puts "Error: Unable to open #{PID_PATH} for reading:\n\t" +
        "(#{e.class}) #{e.message}"
  end

  pid.to_i
end

def remove_pidfile
 begin
   File.unlink(PID_PATH)
  rescue => e
    STDERR.puts "ERROR: Unable to unlink #{path}:\n\t" +
      "(#{e.class}) #{e.message}"
    exit
  end
end

def process_exists?
  begin
    pid = get_pid
    return false unless pid
    Process.kill(0, pid)
    true
  rescue Errno::ESRCH, TypeError # "PID is NOT running or is zombied
    false
  rescue Errno::EPERM
    STDERR.puts "No permission to query #{pid}!";
  rescue => e
    STDERR.puts "(#{e.class}) #{e.message}:\n\t" +
      "Unable to determine status for #{pid}."
    false
  end
end

def stop
  begin
    pid = get_pid
    STDERR.puts "pid : #{pid}"
    while true do
      Process.kill("TERM", pid)
      Process.wait(pid)
      sleep(0.1)
    end
    puts "here"
  rescue Errno::ESRCH # no more process to kill
    remove_pidfile
    STDOUT.puts 'Stopped the process'
  rescue => e
    STDERR.puts "unable to terminate process: (#{e.class}) #{e.message}"
  end
end

def start
  #if process_exists?
  #  STDERR.puts "The process #{EXEC} already running. Restarting the process"
  #  stop
  #end
  pid = Spoon.spawnp EXEC, *ARGV
  create_pid(pid)
  Process.setsid
  #at_exit do
  #  remove_pidfile
  #end

  Dir::chdir(WORK_PATH)
  File::umask(0)
  #STDIN.reopen("/dev/null", 'r')
  #STDOUT.reopen("/dev/null", "w")
  #STDERR.reopen("/dev/null", "w")
end

if ARGV[0] == 'start'
  start
elsif ARGV[0] == 'stop'
  stop
elsif ARGV[0] == 'restart'
  stop
  start
else
  STDERR.puts "Usage: tts_main.rb <start|stop|restart>"
  exit!
end

exec.rb

#!/usr/bin/env jruby
#
#

while true 
  puts 'in loop'
  sleep 2.5
end