SpanId changes on WebClient request

[gabriel-cardenete-movile]

I am doing a simple HTTP request with WebClient, and the spanId is changing.
I noticed that this doesn't happen in Finchley.RELEASE, but is happening on Greenwich.SR2

I have the following code:

restTemplate.getForObject(
        "https://github.com",
        String::class.java
)

logger.info("no spanId changes")

webClient.get()
        .uri("https://github.com")
        .retrieve()
        .bodyToMono(String::class.java)
        .block()

logger.info("spanId changed!")

Example output:

[c177ebd3831cc307-c177ebd3831cc307] no spanId changes
[c177ebd3831cc307-bcdfe282f4b59a0c] spanId changed!

Full project: https://github.com/gabriel-cardenete-movile/sleuth-webclient-problem

Am I doing something wrong here?

Thanks in advance!

[marcingrzejszczak]

Could you please always first verify an issue against the latest stable release before filing it? Greenwich.sr2 is the latest one

[gabriel-cardenete-movile]

Sorry, I checked with Greenwich.SR2 and the problem still happens.

[marcingrzejszczak]

We have working code with webflux. You can check the samples here https://github.com/spring-cloud-samples/sleuth-documentation-apps

I wonder why do you have both resttemplate and webclient together. You should pick only one either webmvc or webflux

[gabriel-cardenete-movile]

I was testing both, to see if normally the request should change the current spanId. If I don't use RestTemplate, the problem still occurs.

Sleuth doesn't work correctly with webmvc and webflux at the same time?

[marcingrzejszczak]

You shouldn't have webmvc and webflux at the same time in your application. It's not a matter of sleuth but boot.

[marcingrzejszczak]

You shouldn't have webmvc and webflux at the same time in your application. It's not a matter of sleuth but boot.

[gabriel-cardenete-movile]

I removed webmvc dependencies, and it still changes spanId after a WebClient request. Again, I tried with Finchley.RELEASE and it works fine.
Am I missing something else here?

[marcingrzejszczak]

Please check out the samples and write your code in the same way. If you're using webflux please make all the controllers return flux or mono.

[gabriel-cardenete-movile]

I ran the samples project with zipkin (start_with_zipkin_server.sh), and the output of service1 was the following:

 INFO [service1,ebb620aa0f57a20b,ebb620aa0f57a20b,true] i.s.c.s.docs.service1.Service2Client     : Hello from service1. Setting baggage foo=>bar
 INFO [service1,ebb620aa0f57a20b,ebb620aa0f57a20b,true] i.s.c.s.docs.service1.Service2Client     : Super secret baggage item for key [baggage] is [null]
 INFO [service1,ebb620aa0f57a20b,ebb620aa0f57a20b,true] i.s.c.s.docs.service1.Service2Client     : Hello from service1. Calling service2
DEBUG [service1,ebb620aa0f57a20b,ebb620aa0f57a20b,true] .s.c.s.i.w.c.TraceExchangeFilterFunction : Instrumenting WebClient call
DEBUG [service1,ebb620aa0f57a20b,ebb620aa0f57a20b,true] .s.c.s.i.w.c.TraceExchangeFilterFunction : Handled send of RealSpan(ebb620aa0f57a20b/fc1f575e0c12ff06)
 INFO [service1,ebb620aa0f57a20b,fc1f575e0c12ff06,true] i.s.c.s.docs.service1.Service2Client     : Got response from service2 [Hello from service2, response from service3 [Hello from service3] and from service4 [Hello from service4]]
 INFO [service1,ebb620aa0f57a20b,fc1f575e0c12ff06,true] i.s.c.s.docs.service1.Service2Client     : Service1: Baggage for [key] is [foo]

Again, the spanId changed after a WebClient request.

[marcingrzejszczak]

I'll investigate it once I have some spare time.