Micrometer Tracing - Quick Reference

Full Reference: See advanced.md for custom ObservationConvention, baggage propagation, logging integration, metrics, async tracing, and testing patterns.

Deep Knowledge: Use mcp__documentation__fetch_docs with technology: micrometer-tracing for comprehensive documentation.

Dependencies

<!-- Micrometer Tracing Bridge (choose one) --> <!-- For Brave (Zipkin) --> <dependency> <groupId>io.micrometer</groupId> <artifactId>micrometer-tracing-bridge-brave</artifactId> </dependency>

<!-- For OpenTelemetry --> <dependency> <groupId>io.micrometer</groupId> <artifactId>micrometer-tracing-bridge-otel</artifactId> </dependency>

<!-- Reporter (choose one) --> <dependency> <groupId>io.zipkin.reporter2</groupId> <artifactId>zipkin-reporter-brave</artifactId> </dependency>

Configuration

spring: application: name: order-service

management: tracing: sampling: probability: 1.0 # Sample 100% in dev, lower in prod zipkin: tracing: endpoint: http://localhost:9411/api/v2/spans

logging: pattern: level: "%5p [${spring.application.name:},%X{traceId:-},%X{spanId:-}]"

Core Concepts

┌─────────────────────────────────────────────────────────────┐ │ Trace (End-to-End Request) │ │ TraceId: abc123 │ │ │ │ ┌──────────────────┐ │ │ │ Span: API Gateway│ SpanId: 001 (Parent) │ │ └────────┬─────────┘ │ │ │ │ │ ┌────────▼─────────┐ ┌─────────────────┐ │ │ │ Span: Order Svc │ │ Span: User Svc │ │ │ │ SpanId: 002 │ │ SpanId: 003 │ │ │ └──────────────────┘ └─────────────────┘ │ └─────────────────────────────────────────────────────────────┘

Automatic Instrumentation

Spring Boot 3 auto-instruments:

• HTTP Server (Spring MVC, WebFlux)

• HTTP Client (RestTemplate, WebClient, RestClient)

• JDBC, Kafka, RabbitMQ, Redis, MongoDB

• Scheduled Tasks

Using Observation API

@Service @RequiredArgsConstructor public class OrderService {

private final ObservationRegistry observationRegistry;

public Order processOrder(OrderRequest request) {
    return Observation.createNotStarted("order.process", observationRegistry)
        .lowCardinalityKeyValue("order.type", request.getType())
        .highCardinalityKeyValue("order.id", request.getId())
        .observe(() -> {
            Order order = createOrder(request);
            validateOrder(order);
            return saveOrder(order);
        });
}

}

Using @Observed Annotation

@Configuration public class ObservationConfig { @Bean public ObservedAspect observedAspect(ObservationRegistry registry) { return new ObservedAspect(registry); } }

@Service public class PaymentService {

@Observed(
    name = "payment.process",
    contextualName = "process-payment",
    lowCardinalityKeyValues = {"payment.method", "credit_card"}
)
public PaymentResult processPayment(PaymentRequest request) {
    return paymentGateway.charge(request);
}

}

HTTP Client Tracing

@Configuration public class RestClientConfig { @Bean public RestClient restClient(RestClient.Builder builder) { return builder .baseUrl("http://order-service") .build(); // Auto-instrumented in Spring Boot 3 } }

Best Practices

Do Don't

Use low cardinality for tags High cardinality in metrics

Sample appropriately in prod 100% sampling in production

Propagate context in async Lose trace context

Use meaningful span names Generic names like "process"

Include traceId in logs Log without correlation

Production Configuration

management: tracing: sampling: probability: 0.1 # Sample 10% in production zipkin: tracing: endpoint: ${ZIPKIN_URL:http://zipkin:9411}/api/v2/spans metrics: tags: application: ${spring.application.name} environment: ${ENVIRONMENT:development}

Checklist

• Sampling rate configured

• Trace exporter configured (Zipkin/Jaeger/OTLP)

• Logging includes traceId/spanId

• Baggage propagation configured

• Async context propagation working

• Custom observations for business ops

• Metrics exported to monitoring

• Health checks include tracing

• Error tracking in spans

• Performance overhead measured

Reference

• Micrometer Tracing Docs

• Spring Boot Observability