Rcb - Ruby Circuit Breaker

Circuit Breaker implementation for/by Ruby.
CircuitBreaker is a great pattern to build robust system consists of bunch of microservices.

• Close
  • An operational state
• Open
  • A not operational state
• Half Open
  • On the way of it's state to Close from Open.

Add this line to your application's Gemfile:

gem 'rcb'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install rcb

To use rcb, insert this line:

require 'rcb'

Add configuration with specifying tag like:

Rcb.configure('fooo.com') do |config|
    config.open_condition.max_failure_count 1
    config.open_condition.window_msec 1000
    config.reset_timeout_msec 100
end

Rcb.configure('hoge.com') do |config|
    config.open_condition.max_failure_count 3
    config.open_condition.window_msec 3000
    config.reset_timeout_msec 300
end

These configurations are for both 'fooo.com' and 'hoge.com'.

• open_condition: a condition to decide whether trip to open from close
  • max_failure_count: a threshold for execution failures.
    • if the breaker reaches the given max_failure_count, enters Open state from Close
  • window_msec: a window time(milliseconds) for failures
    • if the breaker catched failures more than window_msec before, they are discarded
• reset_timeout_msec: milliseconds to wait for next try
  • after the given reset_timeout_msec, the circuit breaker enters a Half-Open state from Open

Pass a block to a method Rcb::Instance#run! to apply circuit-breaker to a execution.

Rcb.for('example.com').run! do # pass a block
    if rand(2) == 0
        raise 'fail!'
    else
        true
    end
end

You can see more example in tests.

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/petitviolet/rcb. 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 Rcb project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.