Faith & Code | Reflections by Errong

Spring Boot @Async: Fixing Distributed Tracing Context Propagation Across Threads Have you ever noticed that distributed traces suddenly disappear when your Spring Boot application executes an asynchronous task? A request enters your application, calls a service, and then schedules background work using @Async . The initial request appears correctly in your tracing dashboard, but the background execution is missing—or worse, it appears as an entirely unrelated trace. The problem may not be your tracing backend. It may be that the request's observation context was not propagated to the worker thread. Distributed tracing relies on context: identifiers and other state that connect operations across services and execution boundaries. OpenTelemetry provides mechanisms to propagate this context between services, usually without requiring application code to copy identifiers manually. However, there is another boundary within the same application that is easy to overlook: switching thre...