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)

Reading Kafka from Spark

There are several connectors for Apache Spark. In this case, we are using the Databricks Inc. (the company responsible for Apache Spark) connector for Kafka.

Using this Spark Kafka connector, we can read data with Spark Structured Streaming from a Kafka topic:

 Dataset<Row> inputDataset = spark
.option("kafka.bootstrap.servers", brokers)
.option("subscribe", Constants.getHealthChecksTopic())

Simply by saying Kafka format, we can read a stream from the topic specified in the subscribe option, running on the brokers specified.

At this point in the code, if you invoke the printSchema() method on the inputDataSet, the result will be something similar to Figure 8.1:

Figure 8.1: Print schema output

We can interpret this as follows:

  • The key and the value are binary...