正體中文版: (Ruby) Write service with daemons gem

How to make a ruby script run only one instance at a time? and with start/stop command?

Actually, it’s very simple, just use Daemons gem.

installation (ubuntu):

	sudo gem install daemons

Simplest example: test.rb require ‘rubygems’ require ‘daemons’

	Daemons.run_proc('myproc.rb') do
	 loop do
	 sleep(5)
	 puts "Hello World"
	 end
	end

Than you can use following commands: ruby test.rb [start|stop|restart|run|zap] (Run ‘ruby test.rb’ will get command usage.)

And when you try to run ‘test.rb start’ twice. you will get: ERROR: there is already one or more instance(s) of the program running