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LightIO provides green thread to ruby. Like Golang's goroutine, or Crystal's fiber. In LightIO it is called beam.


require 'lightio'

start =

beams = do
  # LightIO::Beam is green-thread, use it instead Thread do
    # do some io operations in beam

seconds = - start
puts "1000 beams take #{seconds - 1} seconds to create"

LightIO ship ruby stdlib compatible library under LightIO or LightIO::Library namespace, these libraries provide the ability to schedule LightIO beams when IO operations occur.

LightIO also provide a monkey patch, it replaces ruby Thread with LightIO::Thread, and also replaces IO related classes.


require 'lightio'
# apply monkey patch at beginning

require 'net/http'

host = ''
port = 443

start = do do
    Net::HTTP.start(host, port, use_ssl: true) do |http|
      res = http.request_get('/ping')
      p res.code

puts "#{ - start} seconds"

See Examples for detail.

You Should Know

In fact ruby core team already plan to implement Thread::Green in core language, see

It means if ruby implemented Thread::Green, this library has no reason to exist. But as a crazy userland implemented green thread library, it bring lots of fun to me, so I will continue to maintain it, and welcome to use.

See Wiki and Roadmap to get more information.

LightIO is build upon nio4r. Get heavily inspired by gevent, async-io.


Add this line to your application's Gemfile:

gem 'lightio'

And then execute:

$ bundle

Or install it yourself as:

$ gem install lightio


Please see LightIO Wiki for more information.

The following documentations is also usable:



After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.


The gem is available as open source under the terms of the MIT License.

Copyright, 2017-2018, by Jiang Jinyang

Code of Conduct

Everyone interacting in the Lightio projects codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

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