Ratelimitcop

Ratelimitcop is a Redis backed rate limiter. Appropriate for use cases where in-memory rate limiting would not work (i.e rate limiting across multiple processes, servers, apps, etc).

Add this line to your application's Gemfile:

gem 'ratelimitcop'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install ratelimitcop

To rate limit calling a block of code, simply initialize Ratelimitcop with a threshold and interval, then pass the block of code to the execute method. threshold is the maximum number of requests that can be made within a timed interval, where interval is in seconds. execute will automatically block if the execution of your code block will exceed the given rate limit.

Note: You need let Ratelimitcop know how it can connect to your Redis instance (or it will default to localhost, port 6379, as per the Redis gem docs). To do this pass your Redis connection config as a parameter when intializing Ratelimitcop. View the Redis gem docs to see the different ways you can connect Ratelimitcop to your Redis instance.

Here is an example of an API client that uses Ratelimitcop to ensure the API's rate limits are not exceeded.

  require `iex-ruby-client`
  require `ratelimitcop`

  class IEXCloudAPIClient
    def initialize
      # rate limit 100 calls per second
      @limiter = Ratelimitcop.new(
        name: 'iex_cloud_api',
        threshold: 100,
        interval: 1,
        redis: {
          url: ENV['REDIS_URL']
        }
      )

      @client = IEX::Api::Client.new
    end

    def quote(ticker:)
      # regardless of how this method is called it will block if the rate limit is exceeded before trying to run the code block
      @limiter.execute do
        res = @client.quote(URI.encode(ticker))
        res
      end
    end
  end

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/koffeefinance/ratelimitcop. 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 Ratelimitcop project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.