Class: Daemon

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

Defined Under Namespace

Classes: LockError

Class Method Summary collapse

Class Method Details

.daemonize(pid_file, log_file = nil, sync = true) ⇒ Object 



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# File 'lib/daemon.rb', line 8

def self.daemonize(pid_file, log_file = nil, sync = true)
	exit if fork
	Process.setsid # become session leader
	exit if fork # and exits
	# now in child

	# try to lock before we kill stdin/out
	lock(pid_file)

	if log_file
		log = File.open(log_file, 'a')
		log.sync = sync
	else
		log = '/dev/null'
	end

	# disconnect
	STDIN.reopen '/dev/null'
	STDOUT.reopen log
	STDERR.reopen log
end

.lock(pid_file) ⇒ Object

Raises:



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# File 'lib/daemon.rb', line 30

def self.lock(pid_file)
	pf = File.open(pid_file, File::RDWR | File::CREAT)
	raise LockError, pf unless pf.flock(File::LOCK_EX|File::LOCK_NB)
	pf.truncate(0)
	pf.write(Process.pid.to_s + "\n")
	pf.flush

	@pf = pf # keep it open and locked until process exits
end