Timers

Pure Ruby timer collections. Schedule several procs to fire after configurable delays or at periodic intervals.

This gem is especially useful when you are faced with an API that accepts a single timeout but you want to run multiple timers on top of it. An example of such a library is nio4r, a cross-platform Ruby library for using system calls like epoll and kqueue.

Usage

Create a new timer group with Timers.new:

require 'timers'

timers = Timers.new

Schedule a proc to run after 5 seconds with Timers#after:

five_second_timer = timers.after(5) { puts "Take five" }

The five_second_timer variable is now bound to a Timers::Timer object. To cancel a timer, use Timers::Timer#cancel

Once you've scheduled a timer, you can wait until the next timer fires with Timers#wait:

# Waits 5 seconds
timers.wait

# The script will now print "Take five"

You can schedule a block to run periodically with Timers#every:

every_five_seconds = timers.every(5) { puts "Another 5 seconds" }

loop { timers.wait }

If you'd like another method to do the waiting for you, e.g. Kernel.select, you can use Timers#wait_interval to obtain the amount of time to wait. When a timeout is encountered, you can fire all pending timers with Timers#fire:

loop do
  interval = timers.wait_interval
  ready_readers, ready_writers = select readers, writers, nil, interval

  if ready_readers || ready_writers
    # Handle IO
    ...
  else
    # Timeout!
    timers.fire
  end
end

License

Copyright (c) 2012 Tony Arcieri. Distributed under the MIT License. See LICENSE for further details.