Architecting a Robust Authentication Microservice: Should It Handle CRUD and User Settings?

When designing an authentication microservice, it's critical to clearly define its responsibilities to maintain a clean and scalable architecture. One key decision is whether to incorporate CRUD (Create, Read, Update, Delete) operations and user settings management within the authentication microservice or to delegate these functions to dedicated services. This article examines the responsibilities, pros, cons, and recommended approach for architecting an authentication microservice in this context.

Responsibilities of an Authentication Microservice

Core Authentication Functions

User Registration: Handle the creation of new user accounts. Login/Logout: Manage user sessions and token generation. Password Management: Support secure password resets and updates.

User CRUD Operations

Create: Registration can be part of the authentication service. Read: Fetching user details can be handled, but consider if this data is sensitive or if it should be fetched from a user profile service. Update: Updating user information like email or password can be in scope but changes that affect user roles or permissions may be better suited for another service. Delete: Account deletion can be part of the authentication service, ensuring all authentication tokens are invalidated.

User Settings

User preferences/settings like notification preferences can be part of the authentication service if they are closely tied to user identity and authentication. However, more complex settings may be better handled by a dedicated user profile or settings service.

Pros and Cons of Handling CRUD and Settings in Auth Service

Pros

Simplicity: Fewer services to manage, which can simplify development and deployment. Consistency: All user-related actions are centralized, making it easier to enforce security policies.

Cons

Monolithic Growth: The service may become too large and complex, leading to maintenance challenges. Single Responsibility Principle: Violating this principle can make the service harder to manage and scale.

Recommended Approach

Separation of Concerns

Consider having a dedicated user service that handles user CRUD and settings while the authentication service focuses solely on authentication-related tasks.

Service Interaction

Allow the authentication service to communicate with the user service for necessary operations, ensuring that each service maintains its specific responsibilities.

Security

Regardless of where CRUD operations are handled, ensure that all endpoints are secured and that sensitive information is protected.

Conclusion

In summary, while it is possible for an authentication microservice to handle user CRUD and settings, it is often more beneficial to separate these responsibilities into dedicated services. This promotes better scalability, maintainability, and adherence to best practices in microservice architecture.