Timers for Ruby

Collections of one-shot and periodic timers, intended for use with event loops.

Does not require Celluloid! Though this gem was originally written to provide the timer subsystem for Celluloid, it can be used independently in any sort of event loop context, or can provide a purely timer-based event loop itself.

Supported platforms

Ruby 2.0, 2.1, 2.2, and 2.3
JRuby 9000

Usage

Create a new timer group with Timers::Group.new:

require 'timers'

timers = Timers::Group.new

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

# Waits 5 seconds
timers.wait

# The script will now print "Take five"

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

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

loop { timers.wait }

You can also schedule a block to run immediately and periodically with Timers::Group#now_and_every:

now_and_every_five_seconds = timers.now_and_every(5) { puts "Now and in 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::Group#wait_interval to obtain the amount of time to wait. When a timeout is encountered, you can fire all pending timers with Timers::Group#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

You can also pause and continue individual timers, or all timers:

paused_timer = timers.every(5) { puts "I was paused" }

paused_timer.pause
10.times { timers.wait } # will not fire paused timer

paused_timer.resume
10.times { timers.wait } # will fire timer

timers.pause
10.times { timers.wait } # will not fire any timers

timers.resume
10.times { timers.wait } # will fire all timers

License

Distributed under the MIT License. See LICENSE file for further details.