It's my day 73 of the #100DaysOfDevOps challenge, in this blog I'll be writing about what I learned today, it's about the best practices for modeling services in a microservices architecture.

Microservices architecture is becoming increasingly popular in the world of software development due to its ability to scale, increase flexibility, and reduce dependencies. One of the key factors in building an effective microservices architecture is the proper modeling of services.

Shared and Hidden Model

Shared models are the common data structures and domain concepts that are used by multiple services. These models should be defined in a separate module and shared across services to avoid duplication and ensure consistency.

Hidden models, on the other hand, are the internal data structures used by the service to perform its function. These models should not be exposed to other services and should only be used internally.

Modules and Services

In a microservices architecture, each service should be responsible for a specific business capability or function. This means that the codebase of the service should be organized into modules that are focused on a specific area of functionality.

Each module should be designed to be independent, testable, and easy to deploy. This means that each module should have a clear purpose, well-defined interfaces, and be able to function independently of other modules.

When designing a microservice, it's important to keep in mind the overall architecture and how the service fits into the system as a whole. This means that each service should be designed to be interoperable with other services and be able to communicate effectively using APIs and messaging systems.

Identifying Services

When identifying services, it is important to focus on business capabilities rather than technical capabilities. A service should be responsible for a specific business capability or domain, such as user management or payment processing. This helps to ensure that services are cohesive and focused on specific goals, rather than becoming bloated and difficult to maintain.

Service Boundaries

Service boundaries should be clearly defined to prevent overlap between services. Boundaries should be based on business capabilities and should be well-communicated among team members to ensure that each service is responsible for a unique and specific domain.

Service Contracts

Service contracts should be defined for each service, which specifies the interactions and expectations of the service. This helps to ensure that services are decoupled and can evolve independently. Service contracts can be defined using protocols such as REST or SOAP.

Service Implementation

When implementing services, it is important to follow the principles of loose coupling and high cohesion. This means that services should be designed to minimize dependencies on other services and that each service should be focused on a specific goal or capability.

Premature Decomposition

It is tempting to decompose a monolithic system into microservices as soon as possible, but this can be a costly mistake, especially if you are new to the domain. In many ways, having an existing codebase you want to decompose into microservices is much easier than trying to go to microservices from the beginning.

Premature decomposition can lead to several issues, such as overcomplicating the architecture and creating too many services, which can negatively impact performance and increase maintenance costs. It is important to carefully consider the services that are needed and how they will interact before decomposing the system.

What makes a good service?

A good microservice should be designed to be loosely coupled, independent, and have a well-defined boundary. This means that the service should have a clear purpose and be able to function independently without relying on other services.

Conclusion

Modeling services is a critical component of building a successful microservices architecture. By following best practices such as identifying services based on business capabilities, defining service boundaries, and implementing services with loose coupling and high cohesion, teams can ensure that their microservices architecture is flexible, scalable, and reliable. Avoiding premature decomposition and taking the time to carefully plan the architecture can prevent issues down the line and save costs in the long run.