Building Microservices, 2nd Edition

Chapter 5. Implementing Microservice Communication

As we discussed in the previous chapter, your choice of technology should be driven in large part by the style of communication you want. Deciding between blocking synchronous or nonblocking asynchronous calls, request-response or event-driven collaboration, will help you whittle down what might otherwise be a very long list of technology. In this chapter, we’re going to look at some of the technology commonly used for microservice communication.

Looking for the Ideal Technology

There is a bewildering array of options for how one microservice can talk to another. But which is the right one—SOAP? XML-RPC? REST? gRPC? And new options are always coming out. So before we discuss specific technology, let’s think about what we want out of which technology we pick.

Make Backward Compatibility Easy

When making changes to our microservices, we need to make sure we don’t break compatibility with any consuming microservices. As such, we want to ensure that whatever technology we pick makes it easy to make backward-compatible changes. Simple operations like adding new fields shouldn’t break clients. We also ideally want the ability to validate that the changes we have made are backward-compatible—and have a way to get that feedback before we deploy our microservice into production.

Make Your Interface Explicit

It is important that the interface that a microservice exposes to the outside world is explicit. This means that it is clear to ...