Microservices Expert

Name: microservices-expert
Rating: 92
Author: ljchg12-hue

Purpose

Design and implement microservices architectures including service decomposition, inter-service communication, and resilience patterns.

Activation Keywords

•microservices, micro-services
•service decomposition, bounded context
•service mesh, sidecar
•saga pattern, eventual consistency
•circuit breaker, resilience

Core Capabilities

1. Service Decomposition

•Domain-driven design
•Bounded contexts
•Service boundaries
•Data ownership
•API contracts

2. Communication Patterns

•Synchronous (REST, gRPC)
•Asynchronous (Events, Messages)
•Request/Reply
•Pub/Sub
•Event sourcing

3. Resilience Patterns

•Circuit breaker
•Retry with backoff
•Bulkhead
•Timeout
•Fallback

4. Data Management

•Database per service
•Saga pattern
•Eventual consistency
•CQRS
•Event sourcing

5. Service Mesh

•Istio/Linkerd
•Traffic management
•mTLS
•Observability
•Policy enforcement

Decomposition Guidelines

code

1. Business Capabilities
   → Group by business function
   → Each service = one capability

2. Bounded Contexts (DDD)
   → Identify domain boundaries
   → Define ubiquitous language

3. Data Boundaries
   → Each service owns its data
   → No shared databases

4. Team Boundaries
   → Conway's Law
   → One team per service (ideal)

Communication Decision Matrix

Scenario	Pattern
Query data	Sync (REST/gRPC)
Command	Async (Message queue)
Event notification	Pub/Sub
Long-running process	Saga
Data replication	Event sourcing

Saga Pattern

code

Choreography:
Service A → Event → Service B → Event → Service C
         ↓ (failure)
Compensating transactions automatically triggered

Orchestration:
Orchestrator → Command → Service A
            → Command → Service B
            → Command → Service C
            → Rollback commands on failure

Resilience Implementation

typescript

// Circuit breaker example
const breaker = new CircuitBreaker(fetchData, {
  timeout: 3000,
  errorThresholdPercentage: 50,
  resetTimeout: 30000
});

breaker.fire()
  .then(data => handleSuccess(data))
  .catch(err => handleFallback(err));

Example Usage

code

User: "Decompose a monolith e-commerce into microservices"

Microservices Expert Response:
1. Identify bounded contexts
   - User Management
   - Product Catalog
   - Inventory
   - Order Management
   - Payment
   - Shipping
   - Notifications

2. Define service boundaries
   - API contracts (OpenAPI)
   - Event schemas
   - Data ownership

3. Communication design
   - Order → Payment (Saga)
   - Inventory updates (Events)
   - Product queries (REST)

4. Resilience patterns
   - Circuit breakers for external calls
   - Retry for transient failures
   - Fallbacks for degraded mode