IOPromise

IOPromise is a pattern that allows parallel execution of IO-bound requests (data store and RPCs) behind the abstraction of promises, without needing to introduce the complexity of threading. It uses promise.rb for promises, and nio4r to implement the IO loop.

A simple example of this behaviour is using iopromise-faraday to perform concurrent HTTP requests:

require 'iopromise/faraday'

conn = IOPromise::Faraday.new('https://github.com/')

promises = (1..3).map do
  conn.get('/status')
end

Promise.all(promises).then do |responses|
  responses.each_with_index do |response, i|
    puts "#{i}: #{response.body.strip} #{response.headers["x-github-request-id"]}"
  end
end.sync

Add this line to your application's Gemfile:

gem 'iopromise'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install iopromise

IOPromise itself is a base library that makes it easy to wrap other IO-based workloads inside a promise-based API that back to an event loop. To use IOPromise, look at the following gems:

• iopromise-faraday supports faraday HTTP requests, backed by libcurl/ethon/typhoeus.
• iopromise-dalli supports dalli memcached requests.

After checking out the repo, run bin/setup to install dependencies. Then, run bundle exec 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 the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/theojulienne/iopromise. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

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

Everyone interacting in the iopromise project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.