Principles of microservices

In this section, we will examine some of the principles of the microservices architecture. These principles are a must have when designing and developing microservices. The two key principles are single responsibility and autonomous.

Single responsibility per service

The single responsibility principle is one of the principles defined as part of the SOLID design pattern. It states that a unit should only have one responsibility.

Note

Read more about the SOLID design pattern at http://c2.com/cgi/wiki?PrinciplesOfObjectOrientedDesign.

It implies that a unit, either a class, a function, or a service, should have only one responsibility. At no point do two units share one responsibility, or one unit perform more than one responsibility. A unit with more than one responsibility indicates tight coupling:

As shown in the preceding diagram, Customer, Product, and Order are different functions of an e-commerce application. Rather than building all of them into one application...