Pure Ruby timers collections suitable for use with event loops
Latest commit 6aa4bee Jun 13, 2016 @ioquatix ioquatix committed on GitHub Merge pull request #60 from ferambot/master
Minor fixes



Gem Version Build Status Code Climate Coverage Status MIT licensed

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.


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

# 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
    # Timeout!

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

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

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

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

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

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


Copyright (c) 2012-2016 Celluloid timers project developers (given in the file AUTHORS.md).

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