Microservices architecture mein, EK USER REQUEST OFTEN MULTIPLE SERVICES se GUZARTI hai (jaise Order Service → Inventory Service → Payment Service). AGAR RESPONSE SLOW hai, KAHA BOTTLENECK hai, YE PATA KARNA MUSHKIL ho jaata hai BINA DISTRIBUTED TRACING ke.

Micrometer Tracing (Spring Boot 3.x), HAR REQUEST ko EK "TRACE ID" ASSIGN karta hai, JO POORI journey mein (SAB services ke BEECH, HTTP headers se PROPAGATE hokar) SAME rehta hai. HAR INDIVIDUAL service ke ANDAR, EK "SPAN ID" bhi TRACK hota hai — KITNA TIME us SPECIFIC service ne LIYA.

<dependency>
    <groupId>io.micrometer</groupId>
    <artifactId>micrometer-tracing-bridge-brave</artifactId>
</dependency>
<dependency>
    <groupId>io.zipkin.reporter2</groupId>
    <artifactId>zipkin-reporter-brave</artifactId>
</dependency>

# application.properties:
management.tracing.sampling.probability=1.0
management.zipkin.tracing.endpoint=http://localhost:9411/api/v2/spans

// Application code — KUCH BHI EXTRA LIKHNE ki zaroorat NAHI,
// Trace/Span IDs AUTOMATICALLY generate aur propagate hote hain:
@RestController
public class OrderController {
    @PostMapping("/orders")
    public Order create(@RequestBody OrderDto dto) {
        return orderService.create(dto);   // trace ID AUTOMATICALLY LOGS mein bhi ATTACH hota hai
    }
}