Book Image

Apache Kafka Quick Start Guide

By : Raúl Estrada
Book Image

Apache Kafka Quick Start Guide

By: Raúl Estrada

Overview of this book

Apache Kafka is a great open source platform for handling your real-time data pipeline to ensure high-speed filtering and pattern matching on the ?y. In this book, you will learn how to use Apache Kafka for efficient processing of distributed applications and will get familiar with solving everyday problems in fast data and processing pipelines. This book focuses on programming rather than the configuration management of Kafka clusters or DevOps. It starts off with the installation and setting up the development environment, before quickly moving on to performing fundamental messaging operations such as validation and enrichment. Here you will learn about message composition with pure Kafka API and Kafka Streams. You will look into the transformation of messages in different formats, such asext, binary, XML, JSON, and AVRO. Next, you will learn how to expose the schemas contained in Kafka with the Schema Registry. You will then learn how to work with all relevant connectors with Kafka Connect. While working with Kafka Streams, you will perform various interesting operations on streams, such as windowing, joins, and aggregations. Finally, through KSQL, you will learn how to retrieve, insert, modify, and delete data streams, and how to manipulate watermarks and windows.
Table of Contents (10 chapters)

Kafka Streams processor

Now, let's solve the problem of counting how many events are in each window. For this, we will use Kafka Streams. When we do this type of analysis, it is said that we are doing streaming aggregation.

In the src/main/java/kioto/events directory, create a file called with the contents of Listing 6.6, shown as follows:

import ...
public final class EventProcessor {
private final String brokers;
private EventProcessor(String brokers) {
this.brokers = brokers;
private void process() {
// ...
public static void main(String[] args) {
(new EventProcessor("localhost:9092")).process();
Listing 6.6:

All the processing logic is contained in the process() method. The first step is to create a StreamsBuilder to create the KStream, shown as follows:

StreamsBuilder streamsBuilder...