Designs distributed system architectures, decomposes monoliths into bounded-context services, recommends communication patterns, and produces service boundary diagrams and resilience strategies. Use when designing distributed systems, decomposing monoliths, or implementing microservices patterns — including service boundaries, DDD, saga patterns, event sourcing, CQRS, service mesh, or distributed tracing.
SKILL.md
Microservices Architect
Senior distributed systems architect specializing in cloud-native microservices architectures, resilience patterns, and operational excellence.
Core Workflow
Domain Analysis — Apply DDD to identify bounded contexts and service boundaries.
Validation checkpoint: Each candidate service owns its data exclusively, has a clear public API contract, and can be deployed independently.
Communication Design — Choose sync/async patterns and protocols (REST, gRPC, events).
Validation checkpoint: Long-running or cross-aggregate operations use async messaging; only query/command pairs with sub-100 ms SLA use synchronous calls.
Data Strategy — Database per service, event sourcing, eventual consistency.
Validation checkpoint: No shared database schema exists between services; consistency boundaries align with bounded contexts.
const { v4: uuidv4 } = require('uuid');
function correlationMiddleware(req, res, next) {
req.correlationId = req.headers['x-correlation-id'] || uuidv4();
res.setHeader('x-correlation-id', req.correlationId);
// Attach to logger context so every log line includes the ID
req.log = logger.child({ correlationId: req.correlationId });
next();
}
Propagate x-correlation-id in every outbound HTTP call and Kafka message header.
Circuit Breaker (Python / pybreaker)
import pybreaker
# Opens after 5 failures; resets after 30 s in half-open state
breaker = pybreaker.CircuitBreaker(fail_max=5, reset_timeout=30)
@breaker
def call_inventory_service(order_id: str):
response = requests.get(f"{INVENTORY_URL}/stock/{order_id}", timeout=2)
response.raise_for_status()
return response.json()
def get_inventory(order_id: str):
try:
return call_inventory_service(order_id)
except pybreaker.CircuitBreakerError:
return {"status": "unavailable", "fallback": True}
Saga Orchestration Skeleton (TypeScript)
// Each step defines execute() and compensate() so rollback is automatic.
interface SagaStep<T> {
execute(ctx: T): Promise<T>;
compensate(ctx: T): Promise<void>;
}
async function runSaga<T>(steps: SagaStep<T>[], initialCtx: T): Promise<T> {
const completed: SagaStep<T>[] = [];
let ctx = initialCtx;
for (const step of steps) {
try {
ctx = await step.execute(ctx);
completed.push(step);
} catch (err) {
for (const done of completed.reverse()) {
await done.compensate(ctx).catch(console.error);
}
throw err;
}
}
return ctx;
}
// Usage: order creation saga
const orderSaga = [reserveInventoryStep, chargePaymentStep, scheduleShipmentStep];
await runSaga(orderSaga, { orderId, customerId, items });
