WaterDrop

Gem used to send messages to Kafka in an easy way.

Installation

gem install waterdrop

or add this to your Gemfile:

gem 'waterdrop'

and run

bundle install

Setup

WaterDrop has following configuration options:

Option	Value type	Description
send_messages	Boolean	Should we send messages to Kafka
kafka.hosts	Array	Kafka servers hosts with ports
connection_pool_size	Integer	Kafka connection pool size
connection_pool_timeout	Integer	Kafka connection pool timeout
raise_on_failure	Boolean	Should we raise an exception when we cannot send message to Kafka - if false will silently ignore failures (will just ignore them)

To apply this configuration, you need to use a setup method:

WaterDrop.setup do |config|
  config.send_messages = true
  config.connection_pool_size = 20
  config.connection_pool_timeout = 1
  config.kafka.hosts = ['localhost:9092']
  config.raise_on_failure = true
end

This configuration can be placed in config/initializers and can vary based on the environment:

WaterDrop.setup do |config|
  config.send_messages = Rails.env.production?
  config.connection_pool_size = 20
  config.connection_pool_timeout = 1
  config.kafka.hosts = [Rails.env.production? ? 'prod-host:9091' : 'localhost:9092']
  config.raise_on_failure = Rails.env.production?
end

Usage

Creating and sending standard messages

To send Kafka messages, just create and send messages directly:

message = WaterDrop::Message.new('topic', 'message')
message.send!

message = WaterDrop::Message.new('topic', { user_id: 1 }.to_json)
message.send!

message that you want to send should be either binary or stringified (to_s, to_json, etc).

Using aspects to handle messages

WaterDrop no longer depends on Aspector. Please refer to Aspector documentation if you want to handle messaging in an aspect way.

References

• Karafka framework
• Waterdrop
• Worker Glass
• Envlogic
• Null Logger
• Aspector
• WaterDrop Travis CI
• WaterDrop Code Climate

Note on Patches/Pull Requests

Fork the project. Make your feature addition or bug fix. Add tests for it. This is important so I don't break it in a future version unintentionally. Commit, do not mess with Rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull). Send me a pull request. Bonus points for topic branches.

Each pull request must pass our quality requirements. To check if everything is as it should be, we use PolishGeeks Dev Tools that combine multiple linters and code analyzers. Please run:

bundle exec rake

to check if everything is in order. After that you can submit a pull request.