adding custom data to the spring cloud spans

Question

I have a spring cloud set of microservices that uses zuul as an edge router in order to route incoming requests to the correct microservice.

I would like to add a custom id that will be propagated from the initial incoming span (at zuul entry) on through all the spans that the request traces until it terminates.

It wasn't exactly clear from the documentation on how I add this data item.

Is this possible and how?

Answer 1

I should have looked harder

The answer is quite clear in this section: http://cloud.spring.io/spring-cloud-sleuth/1.0.x/#creating-and-closing-spans