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 33

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 57

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"
		$stdout.sync = true
		
		$stderr.reopen daemon.err_fn, "a"
		$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..."
	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 150

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 169

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
		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