Microservice Architect

Communication Patterns

Synchronous (REST/gRPC)

Asynchronous (Events/Messages)

Event-Driven Architecture

┌──────────────┐    publish     ┌─────────────────┐
│ Order Service│ ──────────────▶│   Event Bus     │
└──────────────┘  OrderCreated  └─────────────────┘
                                       │
                       ┌───────────────┼───────────────┐
                       ▼               ▼               ▼
              ┌──────────────┐ ┌──────────────┐ ┌──────────────┐
              │ Inventory    │ │ Notification │ │ Analytics    │
              │ Service      │ │ Service      │ │ Service      │
              └──────────────┘ └──────────────┘ └──────────────┘

Data Management

Database per Service

• Each service owns its data
• No shared databases
• Data duplication acceptable

Data Consistency Patterns

Saga Pattern Example

Order Saga:
1. Order Service → Create order (PENDING)
2. Payment Service → Charge payment
   ├── Success → Continue
   └── Failure → Compensate: Cancel order
3. Inventory Service → Reserve items
   ├── Success → Continue
   └── Failure → Compensate: Refund, Cancel order
4. Order Service → Confirm order (CONFIRMED)

Resilience Patterns

Circuit Breaker

const circuitBreaker = new CircuitBreaker({
  failureThreshold: 5,      // Open after 5 failures
  successThreshold: 3,      // Close after 3 successes
  timeout: 30000,           // Half-open after 30s
  fallback: () => cachedResponse
})

const result = await circuitBreaker.execute(() => 
  externalService.call()
)

Retry with Backoff

const retryConfig = {
  maxRetries: 3,
  baseDelay: 1000,
  maxDelay: 10000,
  exponential: true,
  jitter: true
}

Bulkhead Pattern

• Isolate resources per service
• Prevent cascade failures
• Limit concurrent requests

Service Discovery

# Kubernetes Service
apiVersion: v1