Node.js, the microservice architecture, and easily testable systems

New capabilities, such as cloud deployment systems and Docker, make it possible to implement a new kind of service architecture. Docker makes it possible to define server process configuration in a repeatable container that's easy to deploy by the millions into a cloud hosting system. It lends itself best to small single-purpose service instances that can be connected together to make a complete system. Docker isn't the only tool to help simplify cloud deployments; however, its features are well attuned to modern application deployment needs.

Some have popularized the microservice concept as a way to describe this kind of system. According to the microservices.io website, a microservice consists of a set of narrowly focused, independently deployable services. They contrast this with the monolithic application deployment pattern where every aspect of the system is integrated into one bundle (such as a single WAR file for a Java EE app server). The microservice model gives developers much needed flexibility.

Some advantages of microservices are as follows:

• Each microservice can be managed by a small team
• Each team can work on its own schedule, so long as the service API compatibility is maintained
• Microservices can be deployed independently, such as for easier testing
• It's easier to switch technology stack choices

Where does Node.js fit in with this? Its design fits the microservice model like a glove:

• Node.js encourages small, tightly focused, single-purpose modules
• These modules are composed into an application by the excellent npm package management system
• Publishing modules is incredibly simple, whether via the NPM repository or a Git URL