Ruby Daemon Example

Example of a daemon process written in ruby with basic start, stop, restart, status controls. This is for UNIX based systems only.

Usage

Put all code that you want to be processed by your daemon into the worker class:

class Worker
  def initialize
    work
  end

  def work
    while $running
      # Do some stuff
      breakable_sleep(300)
    end
  end
end

In our loop we are using $running and breakable_sleep().

Using $running makes sure that our loop will securely finish and not be interrupted in the middle of execution when receiving a TERM signal.

Using breakable_sleep() instead of sleep() allows the daemon process to be terminated during sleep. This is especially helpfull if you have a very long running sleep.

Controlling the daemon

$ ./daemon
-> Usage: daemon {start|stop|restart|status}

$ ./daemon start
-> Starting... done! (PID is 2465)

$ ./daemon status
-> daemon is running

$ ./daemon restart
-> Stopping... done!
-> Starting... done! (PID is 2537)

$ ./daemon stop
-> Stopping... done!

PID File & Process name

On start the daemon will by default create a PID file in it's current working directory with the name of the executable.

So if you name your executable "awesome-daemon" it will be named "awesome-daemon.pid". Additionally the name of your process shown by ps or top command will be "awesome-daemon".