Kafka: The Definitive Guide

Chapter 3. Kafka Producers: Writing Messages to Kafka

Whether you use Kafka as a queue, message bus, or data storage platform, you will always use Kafka by writing a producer that writes data to Kafka, a consumer that reads data from Kafka, or an application that serves both roles.

For example, in a credit card transaction processing system, there will be a client application, perhaps an online store, responsible for sending each transaction to Kafka immediately when a payment is made. Another application is responsible for immediately checking this transaction against a rules engine and determining whether the transaction is approved or denied. The approve/deny response can then be written back to Kafka and the response can propagate back to the online store where the transaction was initiated. A third application can read both transactions and the approval status from Kafka and store them in a database where analysts can later review the decisions and perhaps improve the rules engine.

Apache Kafka ships with built-in client APIs that developers can use when developing applications that interact with Kafka.

In this chapter we will learn how to use the Kafka producer, starting with an overview of its design and components. We will show how to create KafkaProducer and ProducerRecord objects, how to send records to Kafka, and how to handle the errors that Kafka may return. We’ll then review the most important configuration options used to control the producer behavior. We’ll conclude ...