In the era of digitalization, Microservices software architecture enables a system to be sub-divided into a number of smaller, separate and independent services. Microservices patterns generally have multiple names. Before implementing microservices, it has always been asked as what is the correct way of implementing microservices architecture api interaction between two microservices architecture, since the microservices are adopted by most of the industries so the perfect solution for the above question is in great demand.
According to James Lewis and Martin Fowler, there are two types of communication protocols:
- HTTP request response with host APIs
- Lightweight messaging.
Following six types of Microservices patterns that can be found prevalent in Industry. The first two are considered to be introductory patterns, while the other four are the Microservices patterns for managing state. The design patterns are as follows:
When coarse grained services, it makes the entire system too rigid to change. With every change we get some side effects. This leads to the monolithic style of architecture that prevents teams from moving fast.
As per Fine grained soa pattern, entire system is improved as the services into fine grained parts. This means, if there is any change, the scope of side effect is limited to that particular service only. It allows the team to move faster with making new changes.
Layered APIs over fine-grained SOA:
Like every architecture, Microservices software architecture also needs a predefined structure. The optimum structure for Microservices should make it easy to be used by a large organization with multiple teams. It is difficult to visualize all the Microservices of an organization without a structure. Here, different layers of Microservices can be created and group the services by some purpose like- system processes, UI, domains, data etc. These layers bring the structure required to work with a large number of Microservices.
Message-oriented state management over layered APIs:
For Data integrity, it is required to repeat the key business data between multiple Microservices or databases. This is an inefficient way and always have huge chances in errors. In this type of microservices pattern, message queues can be used to share state between multiple Microservices. Each service can subscribe to the key business data that it needs for its operation.
Event-driven state management over layered APIs:
The key business data can go out of sync between multiple Microservices. By implementing a common format for business data, so that it is represented in same format among all the Microservices. This is an extension of Message oriented state management.
Isolating state in layered APIs:
It means it Microservices have its own state, which is its individual feature. Each of them has their own sets of internal data store that constantly reconciles with external data store, isolated pattern supports extremely granular microservices, concentrating on the critical details. It requires an asynchronous event propagation as a means to pass state change from one point to another. One can nominate one Microservices to be the single source of truth for a business entity. It is based on domain driven design, where domains are abstracted in multiple services.
API Composition Pattern:
It is used for performing complex queries in a microservices architecture. It is no more any straightforward approach to use queries that integrates data from multiple services. Implement a query by defining the complete microservices architecture API interaction and API composer, which invoking the services that own the data & perform an in-memory join of the results.