Many of us have been curious about the representation of a Microservice by a hexagon. The reason for this is the inspiration behind the architectural pattern that drives Microservices – the hexagonal architecture. This pattern is also popularly known as ports and adapters in some parts of the globe. In a hexagonal architecture pattern, the code application logic is insulated with an isolation perimeter. This insulation helps a Microservice be unaware of the outside world. The insulation opens specific ports for establishing communication channels to and from the application code. Consuming applications can write adapters against these ports to communicate with the Microservice. The following diagram illustrates a hexagonal pattern for a Microservice:
Hexagonal architecture
Protocols in the case of a Microservice architecture are usually APIs. These APIs are exposed using popular protocols for ease of consumption. Hexagonal architecture lets the Microservice treat all of its consumers alike, whether it is a user interface, test suit, monitoring service, or an automation script.