What does error.type#cancelled mean in an span

[AsLi-IN]

I have recently been seeing numerous instances of error.type#cancelled spans on OpenDashboard, with no other logs being recorded with this span. This issue occurs only when the service attempts to call a downstream service. Can someone explain what this means and how I can avoid it?

I am using Java 21 with Spring Boot 3 WebFlux (asynchronous) and the OpenTelemetry Spring Boot Starter version 2.10.0. Additionally, I have implemented connection response and read timeouts—could these be the cause of the problem?

[pellared]

@open-telemetry/java-approvers, should it be migrated to one of your projects?

[laurit]

This could be moved to https://github.com/open-telemetry/opentelemetry-java-instrumentation/

[laurit]

See https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/instrumentation/spring/spring-webflux/spring-webflux-5.3/library#web-client-instrumentation

[AsLi-IN]

Thanks for sending the document! I appreciate it and now I understand the reason behind it. By the way, is there a way to find out who or what cancelled it? Was it my WebClient timeout setting or maybe the end user?

[laurit]

I don't think so. Cancellation is handled in

opentelemetry-java-instrumentation/instrumentation/spring/spring-webflux/spring-webflux-5.3/library/src/main/java/io/opentelemetry/instrumentation/spring/webflux/v5_3/internal/WebClientTracingFilter.java

Lines 68 to 70 in edbd9aa

	.doOnCancel(
	// no response and no error means that the request has been cancelled
	() -> instrumenter.end(context, request, null, null))

There is no extra info on what caused the cancellation.