FluShot

FluShot is a Chaos Testing tool for Ruby applications. It can inject unexpected behaviors into your system, like adding extra latency to a network request, simulating infinite loops, raising exceptions.

The project is currently in work in progress

Idea:

First we specify the area where the flu shot needs to be injected:

class UserController < ApplicationController
  def show
    # Inject some harmful code, the behaviour is specified in the prespcription definition later.
    FluShot.inject(:user_controller_show)

    User.find(params[:user_id])
  end
end

We can specify vaccines that has a certain behaviour, like adding extra latency:

class Latency < FluShot::Vaccine
  label :latency

  def initialize(params = {})
    sleep(rand(params[:max] - params[:min]) + params[:min])
  end
end

Finally we need to create a prescription for the user_controller_show and inject the latency vaccine:

FluShot::Prescription.for(:user_controller_show) do |prescription|
  prescription.add(:latency, {min: 1000, max: 3000})
end

Installation

Add this line to your application's Gemfile:

gem 'flu_shot'

And then execute:

$ bundle

Or install it yourself as:

$ gem install flu_shot

Usage

Development

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.

Contributing

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

License

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

Code of Conduct

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