Fake::Kafka

It is a drop in replacement for ruby-kafka driver, it works as In-memory driver, useful for development and test environments

Installation

Add this line to your application's Gemfile:

gem 'fake-kafka'

And then execute:

$ bundle

Or install it yourself as:

$ gem install fake-kafka

Usage

Testing

Add the following lines to replace your kafka driver with the in-memory one.

For example for catbus add the following on you spec/rails_helper.rb

require 'fake/kafka'
Catbus.kafka = Fake::Kafka.new

Cleaning kafka memory (AKA 'databasecleaner')

kafka.reset!

With catbus and rspec you can do something like this within your rails_helper.rb

RSpec.configure do |config|
  ...
  config.around(:each) do |example|
    ...
    Catbus.kafka.reset!
    ...
  end
end

Testing a consumer

 describe 'consume' do
    let(:payload) do
      {
        payload: {
          YOUR_CONTENT_HERE
        },
        event_name: EVENT_NAME
      }
    end
    before do
      Catbus.kafka.deliver_message payload, topic: 'test_YOUR_TOPIC'
    end
    it 'should consume message' do
      expect(Resque).to receive(:enqueue).with(described_class, payload.to_json)
      Catbus.consumer.send(:consume)
    end

Testing a producer

 describe 'produce' do
    let(:payload) do
      {
        payload: {
        	YOUR_CONTENT_HERE
        },
        event_name: EVENT_NAME
      }
    end
    it 'should produce message' do
      expect(Catbus.kafka).to receive(:deliver_message).with(payload.to_json, topic: 'test_YOUR_TOPIC', key: nil)
      YOUR_PRODUCER.process(PARAMS)
    end

Development

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

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/catawiki/fake-kafka.