High cohesion in Microservices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a microservice with high cohesion by focusing on a single business capability.

Microservices

class OrderService {
    public void [1]() {
        // Process order placement logic here
    }
}

Drag options to blanks, or click blank then click option'

AplaceOrder

BhandleUserLogin

CupdateInventory

DsendNotification

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing methods unrelated to the service's main responsibility.

Mixing multiple business capabilities in one service.

The method placeOrder fits the OrderService's responsibility, ensuring high cohesion by focusing on order-related tasks.

2fill in blank

medium

Complete the code to ensure the microservice handles only payment-related tasks, maintaining high cohesion.

Microservices

class PaymentService {
    public void [1]() {
        // Logic to process payment
    }
}

Drag options to blanks, or click blank then click option'

AprocessPayment

BvalidateUserCredentials

CgenerateReport

DmanageShipping

Attempts:

3 left

💡 Hint

Common Mistakes

Adding unrelated methods that reduce cohesion.

Confusing payment processing with other business functions.

processPayment is the correct method for PaymentService, keeping the service focused on payment tasks.

3fill in blank

hard

Fix the error in the microservice design by choosing the method that improves cohesion.

Microservices

class InventoryService {
    public void [1]() {
        // Incorrectly placed user authentication logic
    }
}

Drag options to blanks, or click blank then click option'

AauthenticateUser

BupdateStock

CsendEmail

DprocessOrder

Attempts:

3 left

💡 Hint

Common Mistakes

Keeping unrelated methods in the service.

Mixing authentication logic with inventory management.

updateStock belongs to InventoryService, improving cohesion by focusing on inventory management.

4fill in blank

hard

Fill both blanks to define a microservice with high cohesion by focusing on user profile management.

Microservices

class UserProfileService {
    public void [1]() {
        // Update user profile details
    }
    public void [2]() {
        // Retrieve user profile information
    }
}

Drag options to blanks, or click blank then click option'

AupdateProfile

BprocessPayment

CgetProfile

DsendNotification

Attempts:

3 left

💡 Hint

Common Mistakes

Including unrelated business logic in the service.

Mixing different responsibilities in one service.

updateProfile and getProfile are focused on user profile tasks, ensuring high cohesion.

5fill in blank

hard

Fill all three blanks to design a microservice with high cohesion by focusing on shipping operations.

Microservices

class ShippingService {
    public void [1]() {
        // Schedule shipment
    }
    public void [2]() {
        // Track shipment status
    }
    public void [3]() {
        // Calculate shipping cost
    }
}

Drag options to blanks, or click blank then click option'

AscheduleShipment

BtrackShipment

CcalculateShippingCost

DprocessUserLogin

Attempts:

3 left

💡 Hint

Common Mistakes

Adding unrelated methods that reduce cohesion.

Mixing user management with shipping logic.

All chosen methods relate to shipping operations, keeping the ShippingService focused and cohesive.

Practice

1. What does high cohesion mean in microservices architecture?

easy

A. Using a single database for all microservices

B. Splitting every function into separate services regardless of relation

C. Combining unrelated tasks to reduce the number of services

D. Grouping related tasks and responsibilities within a single service

Solution

1. Step 1: Understand the meaning of cohesion

   Cohesion means how closely related the tasks inside a module or service are.

2. Step 2: Apply cohesion to microservices

   High cohesion means grouping related tasks in one service to keep it focused and manageable.

3. Final Answer:

   Grouping related tasks and responsibilities within a single service -> Option D

4. Quick Check:

   High cohesion = grouping related tasks [OK]

Hint: High cohesion means related tasks stay together [OK]

Common Mistakes:

• Thinking high cohesion means splitting every function separately
• Confusing cohesion with coupling
• Believing unrelated tasks should be combined
• Assuming database design defines cohesion

2. Which of the following is the correct way to describe a microservice with high cohesion?

easy

A. A service that manages all user-related operations like profile, login, and preferences

B. A service that mixes order processing and inventory updates randomly

C. A service that handles user authentication and payment processing

D. A service that only stores data without any business logic

Solution

1. Step 1: Identify related tasks in options

   A service that manages all user-related operations like profile, login, and preferences groups user-related operations which are closely related.

2. Step 2: Check other options for unrelated tasks

   Options A and B mix unrelated tasks; D lacks business logic, so not cohesive.

3. Final Answer:

   A service that manages all user-related operations like profile, login, and preferences -> Option A

4. Quick Check:

   High cohesion = related user tasks together [OK]

Hint: Look for grouping of related tasks in one service [OK]

Common Mistakes:

• Choosing options that mix unrelated responsibilities
• Ignoring business logic in cohesion
• Confusing data storage with service responsibility
• Assuming more tasks always mean better cohesion

3. Consider a microservice design where the OrderService handles order creation, payment processing, and shipping updates. What is the likely issue with this design regarding high cohesion?

medium

A. The service has low cohesion because it mixes unrelated responsibilities

B. The service has high cohesion because all tasks relate to orders

C. The service is scalable because it handles multiple tasks

D. The service is loosely coupled with other services

Solution

1. Step 1: Analyze the tasks in OrderService

   Order creation, payment, and shipping are different domains with distinct logic.

2. Step 2: Evaluate cohesion

   Mixing payment and shipping with order creation lowers cohesion because responsibilities differ.

3. Final Answer:

   The service has low cohesion because it mixes unrelated responsibilities -> Option A

4. Quick Check:

   Mixed tasks = low cohesion [OK]

Hint: Different domains in one service reduce cohesion [OK]

Common Mistakes:

• Assuming all order-related tasks are always cohesive
• Confusing scalability with cohesion
• Ignoring domain boundaries
• Believing loosely coupled means high cohesion

4. A microservice named InventoryService currently manages stock levels and supplier payments. What is the best fix to improve high cohesion?

medium

A. Combine InventoryService with OrderService

B. Add customer order tracking to InventoryService

C. Split supplier payments into a separate PaymentService

D. Keep all tasks in InventoryService for simplicity

Solution

1. Step 1: Identify unrelated responsibilities

   Supplier payments are unrelated to stock level management.

2. Step 2: Suggest separation for high cohesion

   Moving payments to a dedicated PaymentService improves cohesion by grouping related tasks.

3. Final Answer:

   Split supplier payments into a separate PaymentService -> Option C

4. Quick Check:

   Separate unrelated tasks to improve cohesion [OK]

Hint: Separate unrelated tasks into different services [OK]

Common Mistakes:

• Adding unrelated tasks to the same service
• Combining unrelated services
• Ignoring cohesion for simplicity
• Confusing cohesion with coupling

5. You are designing a microservices system for an e-commerce platform. To ensure high cohesion, which of the following service groupings is best?

hard

A. UserService (user profiles, payments), OrderService (orders, shipping), InventoryService (stock levels, payments)

B. UserService (user profiles, authentication), OrderService (orders, payments), ShippingService (shipping updates, tracking)

C. One big service handling users, orders, payments, shipping, and inventory

D. Split every function into its own microservice regardless of relation

Solution

1. Step 1: Evaluate grouping of related tasks

   UserService (user profiles, authentication), OrderService (orders, payments), ShippingService (shipping updates, tracking) groups related tasks logically by domain, supporting high cohesion.

2. Step 2: Compare with other options

   UserService (user profiles, payments), OrderService (orders, shipping), InventoryService (stock levels, payments) mixes payments in unrelated services; C is a monolith; D over-splits causing low cohesion.

3. Final Answer:

   UserService (user profiles, authentication), OrderService (orders, payments), ShippingService (shipping updates, tracking) -> Option B

4. Quick Check:

   Group related domain tasks for high cohesion [OK]

Hint: Group by domain responsibilities for high cohesion [OK]

Common Mistakes:

• Mixing unrelated tasks in one service
• Creating too many tiny services
• Building monolithic services
• Ignoring domain boundaries