Why good service boundaries prevent coupling in Microservices - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a service boundary that isolates user data.

Microservices

class UserService:
    def get_user_profile(self, user_id):
        return self.[1].fetch_profile(user_id)

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Aexternal_api

Bcache

Cdatabase

Dlogger

Attempts:

3 left

💡 Hint

Common Mistakes

Using external APIs directly inside the service causes tight coupling.

The service boundary should access its own database to keep data isolated and prevent coupling.

2fill in blank

medium

Complete the code to ensure communication between services uses APIs, not direct database calls.

Microservices

def get_order_details(order_id):
    return [1].call('OrderService', order_id)

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AFileSystem

BApiGateway

CDirectDBConnection

DDatabaseClient

Attempts:

3 left

💡 Hint

Common Mistakes

Calling databases directly from other services increases coupling.

Using an API Gateway ensures services communicate through defined APIs, reducing coupling.

3fill in blank

hard

Fix the error in the service design to avoid tight coupling.

Microservices

class PaymentService:
    def process_payment(self, payment_info):
        # Incorrect: directly accessing OrderService database
        orders = [1].query_orders(payment_info.order_id)
        # process payment logic
        return True

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ACacheService

BOrderDatabase

CPaymentGateway

DOrderServiceAPI

Attempts:

3 left

💡 Hint

Common Mistakes

Using OrderDatabase directly causes tight coupling.

Accessing OrderService via its API avoids direct database coupling.

4fill in blank

hard

Fill both blanks to define a service boundary and communication method that prevent coupling.

Microservices

class InventoryService:
    def check_stock(self, product_id):
        stock = self.[1].get_stock(product_id)
        return stock if stock > 0 else None

class OrderService:
    def place_order(self, product_id):
        available = [2].check_stock(product_id)
        if available:
            # proceed with order
            return True
        return False

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AInventoryDatabase

BInventoryServiceAPI

CDirectDBConnection

DCacheLayer

Attempts:

3 left

💡 Hint

Common Mistakes

Using InventoryDatabase or DirectDBConnection causes tight coupling.

Both service boundary and communication use the InventoryService API to avoid coupling.

5fill in blank

hard

Fill all three blanks to implement a loosely coupled microservice interaction.

Microservices

class ShippingService:
    def ship_order(self, order_id):
        order_info = [1].get_order(order_id)
        if order_info and order_info.status == [2]:
            [3].initiate_shipping(order_id)
            return True
        return False

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AOrderServiceAPI

B'PAID'

CLogisticsServiceAPI

DOrderDatabase

Attempts:

3 left

💡 Hint

Common Mistakes

Accessing OrderDatabase directly or skipping status check causes coupling.

ShippingService calls OrderService via API, checks for 'PAID' status, and calls LogisticsService API to ship, avoiding direct database coupling.