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Microservicessystem_design~12 mins

Loose coupling in Microservices - Architecture Diagram

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System Overview - Loose coupling

This system demonstrates loose coupling in a microservices architecture. Each service operates independently and communicates asynchronously through a message queue. This design improves scalability and fault tolerance by minimizing direct dependencies between services.

Architecture Diagram
User
  |
  v
Load Balancer
  |
  v
API Gateway
  |
  v
+----------------+       +----------------+       +----------------+
| Service A      |<----->| Message Queue  |<----->| Service B      |
| (Order Service)|       | (Async Broker) |       | (Inventory)    |
+----------------+       +----------------+       +----------------+
       |                                              |
       v                                              v
+----------------+                             +----------------+
| Database A     |                             | Database B     |
| (Orders DB)    |                             | (Inventory DB) |
+----------------+                             +----------------+
Components
User
user
Initiates requests to the system
Load Balancer
load_balancer
Distributes incoming requests evenly to API Gateway instances
API Gateway
api_gateway
Routes requests to appropriate microservices
Service A (Order Service)
service
Handles order creation and processing
Service B (Inventory Service)
service
Manages inventory updates and queries
Message Queue (Async Broker)
message_queue
Enables asynchronous communication between services to reduce direct dependencies
Database A (Orders DB)
database
Stores order data for Service A
Database B (Inventory DB)
database
Stores inventory data for Service B
Request Flow - 10 Hops
User → Load Balancer
Load Balancer → API Gateway
API Gateway → Service A (Order Service)
Service A (Order Service) → Database A (Orders DB)
Service A (Order Service) → Message Queue (Async Broker)
Message Queue (Async Broker) → Service B (Inventory Service)
Service B (Inventory Service) → Database B (Inventory DB)
Service A (Order Service) → API Gateway
API Gateway → Load Balancer
Load Balancer → User
Failure Scenario
Component Fails:Message Queue (Async Broker)
Impact:Services cannot communicate asynchronously; inventory updates are delayed or lost, causing data inconsistency.
Mitigation:Implement message queue replication and persistence; use fallback retries and alerting to restore message flow quickly.
Architecture Quiz - 3 Questions
Test your understanding
Which component ensures that Service A and Service B do not depend on each other directly?
AAPI Gateway
BLoad Balancer
CMessage Queue (Async Broker)
DDatabase A
Design Principle
This architecture shows loose coupling by using asynchronous messaging between independent services. Each service owns its data and communicates via a message queue, reducing direct dependencies and improving system resilience and scalability.