Single responsibility per service in Microservices - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why is single responsibility important in microservices?

Imagine you have a microservice that handles both user authentication and payment processing. What is the main risk of combining these responsibilities in one service?

A It increases the chance of bugs affecting unrelated features and complicates scaling.

B It makes the service easier to maintain and scale independently.

C It reduces network latency between authentication and payment functions.

D It allows the service to use fewer resources by sharing code.

💡 Hint

Think about how mixing different tasks can affect updates and failures.

Combining unrelated responsibilities increases complexity, making the service harder to maintain and scale. Bugs in one area can impact others, violating the single responsibility principle.

❓ Architecture

intermediate

Identifying single responsibility in service design

You are designing a microservice for an online bookstore. Which service design best follows the single responsibility principle?

A A single service that handles all business logic and database access.

B Separate services: one for user accounts, one for orders, and one for inventory management.

C One service for user accounts and orders, another for inventory and shipping.

D A service that manages user accounts, orders, and inventory all together.

💡 Hint

Think about dividing responsibilities so each service does one main job.

Separating user accounts, orders, and inventory into distinct services ensures each service has a clear, focused responsibility, improving maintainability and scalability.

❓ scaling

advanced

Scaling microservices with single responsibility

You have two microservices: Service A handles user profiles, and Service B handles payment processing. Service B experiences high load during sales. What is the best scaling approach?

A Scale both Service A and Service B equally to handle the load.

B Merge Service A and B to share resources and scale together.

C Scale Service A only because user profiles are critical.

D Scale only Service B independently since it has high load.

💡 Hint

Consider which service is under stress and how single responsibility helps.

Because Service B handles payments and faces high load, scaling it independently is efficient. Single responsibility allows scaling only the needed service without affecting others.

❓ tradeoff

advanced

Tradeoffs of strict single responsibility in microservices

What is a potential downside of applying single responsibility too strictly by creating many tiny microservices?

A It can increase communication overhead and operational complexity.

B It simplifies deployment and reduces network calls.

C It eliminates the need for service discovery and load balancing.

D It reduces fault isolation and makes debugging harder.

💡 Hint

Think about what happens when many small services need to talk to each other.

Too many tiny services increase network communication and make managing deployments, monitoring, and debugging more complex.

❓ component

expert

Designing a microservice with single responsibility

You need to design a microservice responsible only for sending email notifications. Which components should this service include to follow single responsibility best?

A Email sending logic, payment processing, and user authentication.

B User management, email template storage, and email sending logic.

C Email sending logic, email template storage, and retry mechanism for failed emails.

D Email sending logic and order processing.

💡 Hint

Focus on components directly related to sending emails.

The service should include email sending, template storage, and retry logic because all relate to the single responsibility of email notifications.