Sampa Karafka and Sinatra app

Karafka & Sinatra

Karafka is a framework used to simplify Apache Kafka based Ruby applications development.

Sinatra is a DSL for quickly creating web applications in Ruby with minimal effort.

Goal

This repository was created for a sample application that uses a web api and also listens and writes to Apache Kafka topics.

Organization

Configuration

Defined on karafka.rb, this app assumes you have Kafka running on 127.0.0.1:9092. In this file, it's also defined a consumer group for the app named default_group with two topics (with consumers and responders) example and response.

Api configuration and a sample endpoint is defined on api.rb.

API

A simple GET endpoint /frank-says that is responsible for publising a message using a Responder.

Responders

Are the ones responsible for writing messages to a given Kafka topic. They are:

• Responders::Foobar, used on the sinatra sample endpoint to send a message to the example topic.
• Responders::Example, used by the Consumers::Example (defined on karafka config file), responding the consumer's message to the response topic.

Consumers

Are the ones responsable for listening to Kafka topics. They are:

• Consumers::Example, that listens to the topic example (defined on karafka config file), logs the consumed message and responds to the response topic using Responders::Example (also defined on karafka config file).
• Consumers::Response, that listens to the topic response (defined on karafka config file) and logs the consumed message.

Running the app

• Run karafka server on your terminal to start the Karafka server.
• Run bundle exec ruby api.rb on another tab of your terminal to start Sinatra.