WebClient instrumentation in spring sleuth

I'm wondering whether sleuth has reactive WebClient instrumentation supported.

I did't find it from the document:

Instruments common ingress and egress points from Spring applications (servlet filter, async endpoints, rest template, scheduled actions, message channels, Zuul filters, and Feign client).

My case:

I may use WebClient in either a WebFilter or my rest resource to produce Mono.

And I want:

A sub span auto created as child of root span
trace info propagated via headers

If the instrumentation is not supported at the moment, Am I supposed to manually get the span from context and do it by myself like this:

OpenTracing instrumentation on reactive WebClient

Thanks

Leon

Solution

If you go to Sleuth's documentation for the Finchley release train, and you do find and you search for WebClient you'll find it - https://cloud.spring.io/spring-cloud-static/Finchley.RC2/single/spring-cloud.html#__literal_webclient_literal . In other words we do support it out of the box.

UPDATE:

New link - https://docs.spring.io/spring-cloud-sleuth/docs/current/reference/html/integrations.html#sleuth-http-client-webclient-integration

let me paste the contents

3.2.2. WebClient

This feature is available for all tracer implementations.

We inject a ExchangeFilterFunction implementation that creates a span and, through on-success and on-error callbacks, takes care of closing client-side spans.

To block this feature, set spring.sleuth.web.client.enabled to false. You have to register WebClient as a bean so that the tracing instrumentation gets applied. If you create a WebClient instance with a new keyword, the instrumentation does NOT work.