OpenTelemetry and tagged baggage does not create a tag

[mhalbritter]

I have this code:

    @GetMapping("/call1")
    public String call1() {
        ScopedSpan span = this.tracer.startScopedSpan("call1");
        try {
            try (BaggageInScope scope7 = this.tracer.createBaggageInScope("t1", "t1-v1")) {
// ...
            }
        } catch (RuntimeException | Error ex) {
            span.error(ex);
            throw ex;
        } finally {
            span.end();
        }
    }

and t1 configured as tag fields on the OtelBaggageManager.

While it creates the span, the t1 tag is missing.

If I add

this.tracer.getBaggage("t1").makeCurrent("t1-v1").close();

to the try-with-resources, the tag appears.

[marcingrzejszczak]

@mhalbritter so in Micrometer 1.0.x I fixed the bug in OTel and that got propagated forward.

However with Brave it works with 1.0.x if you add the separate tag setting handler, but it won't work with 1.1.x onwards. That's because we've aligned that the Brave's baggage should work like OTel one which means that it has a value only within the scope. The handler however is called after the span is finished so it's way after the baggage scope gets closed. So what I did is I added a constructor for BraveBaggageManager that requires to pass the list of tags to it (it's a non-breaking change cause the default constructor assumes that there are no tag keys) and whenever a baggage is created I will tag the span (instead of doing it at the end of span I do it at the beginning of baggage). That means that Boot will need to align here to change the way the BBM bean is being created.

The only potential problem I see is that someone creates a span but doesn't it put it in scope and wants to set a baggage on it, but baggage as such must live within a scope so I can't imagine someone creating a span not in scope and then a baggage in scope. If someone wants baggage they need to have a span in scope too 🤷

[mhalbritter]

Thanks. I've opened spring-projects/spring-boot#38724.

[nikakis]

@marcingrzejszczak We have the following issue after upgrading spring boot to 3.1.4 version.

At the code snipet below we invoke the set method for example with x-user-id as key and user-id as value. When we try to fetch the x-user-id from the baggage it returns a null value.

@Override
public void set(String key, @Nullable String value) {
    Baggage baggage = tracer.getBaggage(key);
    TraceContext currentContext = currentTraceContext.context();

    // The default is that baggage set on a child span doesn't
    // bubble up to the parent spans. That means if the child span is ended, the baggage is no longer available.
    // This sets the baggage on every span up to the root. This way it doesn't matter in which child span the
    // baggage is set, it's available on the whole trace.
    while (currentContext != null) {
        baggage.makeCurrent(currentContext, value).close();

        currentContext = traceContextLookup.find(currentContext.traceId(), currentContext.parentId());
    }
}

If we don't invoke the close() method after makeCurrent() everything works properly.

Any idea?

Thanks in advance!

[mhalbritter]

FYI: This is a cross-post from here.

[jonatan-ivanov]

Neither Boot 3.1 nor Micrometer Tracing 1.1 are supported, see: https://spring.io/projects/spring-boot#support
Please try the latest version: Boot 3.3 and Micrometer-Tracing 1.3.

[shakuzen]

Per spring-projects/spring-boot#38724 (comment) I think they tried with Boot 3.3.3 and had the same issue. I think a new issue with a minimal reproducer or code for a unit test would be best to continue the investigation.