Async baggage propagation failed after baggage is closed when using Brave

[wapkch]

When using micrometer-tracing-bridge-brave, async baggage propagation not work after the BaggageInScope has closed, but if using micrometer-tracing-bridge-otel, it worked.

Here is an example:

    @GetMapping
    public void test() {
        ExecutorService executorService = ContextExecutorService.wrap(Executors.newCachedThreadPool(), ContextSnapshot::captureAll);
        try (BaggageInScope baggage = tracer.getBaggage("xyz").makeCurrent("123")) {
            executorService.execute(() -> {
                try {
                    Thread.sleep(3000);
                    String s = tracer.getBaggage("xyz").get();
                    Assert.state(s.equals("123"), "Baggage should be propagated"); // work when using otel, not work when using brave
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            });
        }
    }

[shakuzen]

@wapkch could you share what version of micrometer tracing you're using? Is this still an issue on the latest version?

[wapkch]

@wapkch could you share what version of micrometer tracing you're using? Is this still an issue on the latest version?

After testing with the latest version (1.4.1), I noticed that the behavior between Brave and OTel is consistent. Async baggage propagation doesn’t work in either case, meaning the assertion mentioned above will fail. Is this behavior by design?

[marcingrzejszczak]

So this is the way to go (not like in #928).

The problem is that Baggage is not automatically propagated between threads from Context Propagation unless you register

• https://github.com/micrometer-metrics/tracing/blob/v1.4.1/micrometer-tracing/src/main/java/io/micrometer/tracing/contextpropagation/ObservationAwareBaggageThreadLocalAccessor.java to propagate baggage
• https://github.com/micrometer-metrics/tracing/blob/v1.4.1/micrometer-tracing/src/main/java/io/micrometer/tracing/contextpropagation/ObservationAwareSpanThreadLocalAccessor.java to propagate spans

We describe this in the docs here