Microservices-based architecture can be sub-categorized further….
Can you think how?
1. Microservices — also known as the microservice architecture — is an architectural style that structures an application as a collection of services that are: 1) Highly maintainable and testable 2) Loosely coupled 3) Independently deployable.
2. But, in microservices architecture too, there are different ways to implement it. At a high level, there are two approaches to getting microservices to work together toward a common goal: orchestration and choreography.
3. Orchestration entails actively controlling all elements and interactions like a conductor directs the musicians of an orchestra, while choreography entails establishing a pattern or routine that microservices follow as the music plays, without requiring supervision and instructions.
4. So, in orchestration there is one coordinator which coordinates different mini-services. The coordinates which service to call first, and then which service to call next on the basis of the output of the first service. These are mostly workflow-based systems.
5. In Choreography, there is an event broker and no coordinator. Each service that is subscribed to this event broker, picks up the message from the queue and performs execution. After completion of its task, it publishes the message on the channel and another service performs its tasks asynchronously. This system can be thought of as consisting of a queue like Kafka, SQS, and various services/lambdas performing computations.
6. Both of these methods have their own disadvantages and advantages. In some cases, orchestration is better whereas in others choreography is better.
7. Major advantages of choreography over orchestration:1) Orchestration suffers from tight coupling, whereas choreography offers loose coupling. 2) Orchestration depends on RESTful APIs and hence requires more maintenance due to failures whereas choreography requires less maintenance and is fault-tolerant because it is mostly stateless and messages can be retried.
8. There are some cases too when microservice architecture in itself is not suitable for the system. So, there is no generalized correct way. Designing system is kind of an art and engineers are the artists.
