Building Event-Driven Microservices, 2nd Edition

Chapter 11. Basic Producer and Consumer Microservices

Basic producer and consumer (BPC) microservices ingest events from one or more event streams, apply any necessary transformations or business logic, and emit any necessary events to output event streams. Synchronous request-response I/O may also be a part of this workflow, but that topic is covered in more detail in Chapter 17. This chapter focuses strictly on event-driven components.

BPC microservices are characterized by the use of basic consumer and producer clients, which provide only basic functionality for consuming and producing events. They do not include any event scheduling, watermarks, built-in materialization mechanisms, changelogs, or horizontal scaling mechanisms beyond consumer group balancing that are common to the full-featured frameworks discussed in Chapters 12 and 13.

While it is certainly possible for you to develop your own libraries to provide these features, doing this is beyond the scope of this chapter. Thus, you must carefully consider whether the BPC pattern will work for your business requirements.

Producer and consumer clients are readily available in most commonly used languages, lowering the cognitive overhead in getting started with event-driven microservices. The entire workflow of the bounded context is contained within the code of the single microservice application, keeping the responsibilities of the microservice localized and easy to understand. The workflow can also easily be wrapped ...