Developing event-driven asynchronous services

In this section, we will learn how to develop event-driven and asynchronous versions of the create and delete services. The composite service will publish create and delete events on each core service topic and then return an OK response back to the caller without waiting for processing to take place in the core services. This is illustrated in the following diagram:

Figure 7.7: The createCompositeProduct and deleteCompositeProduct parts of the landscape

We will cover the following topics:

• Handling challenges with messaging
• Defining topics and events
• Changes in Gradle build files
• Consuming events in the core services
• Publishing events in the composite service

Handling challenges with messaging

To implement the event-driven create and delete services, we will use Spring Cloud Stream. In Chapter 2, Introduction to Spring Boot, we have already seen how easy it is to publish and consume messages on a topic using Spring Cloud Stream. The programming...