Fibril

Fibril is a pure Ruby library that allows you to use cooperative multitasking inside your Ruby code. It is a similar concept to the event loop in JavaScript, but makes use of context switching through Fibers to prevent the need for callback functions or promises.

Traditionally you might approach concurrency in Ruby through the use of threads combined with concurrency primitives to synchronise critical sections of your code. Fibril takes an alternative approach where instead everything is synchronous and safe from concurrent state mutations unless explicitly told otherwise.

You can use Fibril to yield from a flow of execution while waiting on an asychrouous call and fibril will schedule the same flow to resume as soon the asynchronous call is complete. All without the need for callbacks.

You can be explicit in how you weave your fibrils together to ensure the order in which your multiple tasks execute is deterministic.

You may be interested in Fibril if:

• Your code has many fast operations that are often blocked by slow operations
• You want to use two or more Ruby libraries which require a blocking IO loop together.
• You have multiple IO operations that you wish to execute in parallel while ensuring the rest of your code executes synchronously
• You want to manipulate multiple streams of data in parallel without having to worry about synchronisation across threads.

In scenarios where many IO bound operations are the performance bottleneck of your application Fibril is likely to provide performance benefits. In other scenarios performance should be comparable to that using threads or executing all tasks synchronously.

At its simplest Fibril will allow you to write source code that looks shallow and linear while allowing multiple flows of execution to complete concurrently.

Add this line to your application's Gemfile:

gem 'fibril'

And then execute:

$ bundle

Or install it yourself as:

$ gem install fibril

Read the wiki here and examine the examples in this repository to learn how to use Fibril.

After checking out the repo, run bin/setup to install dependencies. Then, run rake test 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 rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/wouterken/fibril.

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