Class: N::Application

Inherits:
Object
  • Object
show all
Defined in:
lib/n/application.rb

Overview

Application

the default Application object of the Framework.

Direct Known Subclasses

Cluster, Server, Sync::Server

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name = "Unknown") ⇒ Application

Returns a new instance of Application.



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# File 'lib/n/application.rb', line 41

def initialize(name = "Unknown")
	@name = name
	@pidfile = "/tmp/#{@name}.pid"
	@create_time = Time.now()
	@status = :stop
end

Instance Attribute Details

#create_time ⇒ Object

startup time of the application



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# File 'lib/n/application.rb', line 32

def create_time
  @create_time
end

#daemonized ⇒ Object (readonly)

Returns the value of attribute daemonized.



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# File 'lib/n/application.rb', line 34

def daemonized
  @daemonized
end

#description ⇒ Object

credentials of the application



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# File 'lib/n/application.rb', line 22

def description
  @description
end

#name ⇒ Object

credentials of the application



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# File 'lib/n/application.rb', line 22

def name
  @name
end

#pid ⇒ Object (readonly)

the pid of the application



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# File 'lib/n/application.rb', line 37

def pid
  @pid
end

#pidfile ⇒ Object (readonly)

the pid of the application



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# File 'lib/n/application.rb', line 37

def pidfile
  @pidfile
end

#status ⇒ Object

the status of the application use symbols to denote status. valid status symbols:

  • :run = The server is running

  • :stop = The server is stopped



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# File 'lib/n/application.rb', line 29

def status
  @status
end

#title ⇒ Object

credentials of the application



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# File 'lib/n/application.rb', line 22

def title
  @title
end

#version ⇒ Object

credentials of the application



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# File 'lib/n/application.rb', line 22

def version
  @version
end

Instance Method Details

#daemon_pid ⇒ Object

Returns the pid of the running daemon



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# File 'lib/n/application.rb', line 176

def daemon_pid()
	begin
		return File.open(@pidfile).read.chomp.to_i
	rescue
		$log.info "Could not read pid from #{@pidfile}"
		return nil
	end
end

#daemonize ⇒ Object

Run the application as a daemon FIXME: handle logging for daemons. ???: How does this work !?!?



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# File 'lib/n/application.rb', line 151

def daemonize
	unless @daemonized
		trap "SIGCLD", "IGNORE"

		pid = fork()
		
		if pid # parent process
			@pid = pid
			File.open(@pidfile, 'w') {|f| f << "#{pid}\n" }
			exit!
		else # child
			$log.info "Daemon for '#{@name}', process id: #{Process.pid}"
		end

		# change process group and lose control tty
		Process.setpgrp()
	end

	@daemonized = true

	return self
end

#parse_arguments(args = ARGV) ⇒ Object Also known as: exec

FIXME: deleting of arguments is wrong, recode this using GETOPT.



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# File 'lib/n/application.rb', line 51

def parse_arguments(args = ARGV)
     
	opts = OptionParser.new { |opts|
		opts.banner = "Usage: application.rb [action]"

		opts.separator ""
		opts.separator "Specific options:"

  		opts.on("-s", "--start",
  				"Start Navel's Application Server.") { 
			start()
  		}

		opts.on("-S", "--stop",
  				"Stop Navel's Application Server.") { 
			stop()
  		}

		opts.on("-r", "--restart",
  				"Restart Navel's Application Server.") { 
			restart()
  		}

		opts.on("-d", "--daemon",
  				"Run Navel's Application Server as a daemon.") { 
			daemonize()
			start()
  		}

		opts.on_tail("-?", "--help", "Show this message.") {
  			puts opts
    		exit
		}
   }   
	begin
		opts.parse!(args)
	rescue => ex
		puts ex
		puts "Please, either specify a valid option or invoke the usage using -? or --help."
	end
end

#restart ⇒ Object

Override to properly restart the application



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# File 'lib/n/application.rb', line 111

def restart()
	stop()
	start()

	# to allow for chaining
	return self
end

#run ⇒ Object

Begin the application loop. Override this method in your application.



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# File 'lib/n/application.rb', line 142

def run
	# to allow for chaining
	return self
end

#start ⇒ Object 



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# File 'lib/n/application.rb', line 96

def start()
	raise "Application allready started!" unless :stop == @status

	begin		
		run()
	rescue => ex
		puts ex
	end
	
	# to allow for chaining
	return self
end

#stop ⇒ Object

Stop the application. Typically kills ths application daemon.



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# File 'lib/n/application.rb', line 121

def stop
	if dpid = daemon_pid()
		begin
			File.delete(@pidfile)
			Process.kill("SIGKILL", dpid)
			$log.info "Successfully killed #{@name} instance, pid=#{dpid}"
		rescue => ex
			$log.error "Cannot kill #{@name} instance, pid=#{dpid}"
			$log.error ex
		end
	else
		$log.error "Cannot locate pid of running instance!"
	end

	# to allow for chaining
	return self
end