Building Microservices, 2nd Edition

Chapter 2. How to Model Microservices

My opponent’s reasoning reminds me of the heathen, who, being asked on what the world stood, replied, “On a tortoise.” But on what does the tortoise stand? “On another tortoise.”

Rev. Joseph Frederick Berg (1854)

So you know what microservices are and, I hope, have a sense of their key benefits. You’re probably eager now to go and start making them, right? But where to start? In this chapter, we’ll look at some foundational concepts such as information hiding, coupling, and cohesion and understand how they’ll shift our thinking about drawing boundaries around our microservices. We’ll also look at different forms of decomposition you might use, as well as focusing more deeply on domain-driven design being a hugely useful technique in this space.

We’ll look at how to think about the boundaries of your microservices so as to maximize the upsides and avoid some of the potential downsides. But first, we need something to work with.

Introducing MusicCorp

Books about ideas work better with examples. Where possible, I’ll be sharing stories from real-world situations, but I’ve found it’s also useful to have a fictional scenario to work with. Throughout the book, we’ll be returning to this scenario, seeing how the concept of microservices works within this world.

So let’s turn our attention to the cutting-edge online retailer MusicCorp. MusicCorp was until recently just a brick-and-mortar retailer, but after the bottom dropped out of the vinyl record ...