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
			daemon.run
			
			trap("INT") do
				daemon.shutdown
			end
		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 129

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 149

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

	pgid = -Process.getpgid(pid)
	Process.kill("INT", pgid)
	sleep 0.1

	sleep 1 if ProcessFile.running(daemon)

	# 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 process group #{pgid}...".color(:red)
		Process.kill(sig, pgid)

		attempts -= 1
		sleep 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