Building Microservices, 2nd Edition

Chapter 4. Microservice Communication Styles

Getting communication between microservices right is problematic for many due in great part, I feel, to the fact that people gravitate toward a chosen technological approach without first considering the different types of communication they might want. In this chapter, I’ll try and tease apart the different styles of communication to help you understand the pros and cons of each, as well as which approach will best fit your problem space.

We’ll be looking at synchronous blocking and asynchronous nonblocking communication mechanisms, as well as comparing request-response collaboration with event-driven collaboration.

By the end of this chapter you should be much better prepared to understand the different options available to you and will have a foundational knowledge that will help when we start looking at more detailed implementation concerns in the following chapters.

From In-Process to Inter-Process

OK, let’s get the easy stuff out of the way first—or at least what I hope is the easy stuff. Namely, calls between different processes across a network (inter-process) are very different from calls within a single process (in-process). At one level, we can ignore this distinction. It’s easy, for example, to think of one object making a method call on another object and then just map this interaction to two microservices communicating via a network. Putting aside the fact that microservices aren’t just objects, this thinking can get ...