If I register a TextMapPropagator, traceparent goes missing in outbound calls

[avcad]

I implemented an agent extension and registered a TextMapPropagator using AutoConfigurationCustomizerProvider (addPropagatorCustomizer) to propagate the "X-Trace-Level" header. I used this as template:

https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/examples/extension/src/main/java/com/example/javaagent/DemoPropagator.java

I do see the X-Trace-Level header getting injected in outbound calls, but the problem is that these
calls are now missing the traceparent header, so I end up with two independent traces.

Does anybody have any tips for what I am missing here?

Thanks!

[laurit]

The function added with addPropagatorCustomizer is called for each configured propagator. The value returned replaces the propagator given as input. I guess you are replacing the existing w3c tracecontext propagator with your custom one.

[avcad]

Hi @laurit, Thank you, this works.

I have some hesitation with this solution. I want to add my simple propagator to whatever is currently configured. I don't want to potentially replace/mess the existing configuration. Do you know if this is possible?

@Override
public void customize(AutoConfigurationCustomizer autoConfiguration) {
	autoConfiguration.addPropagatorCustomizer(this::configurePropagatorCustomizer);
}

private TextMapPropagator configurePropagatorCustomizer(TextMapPropagator textMapPropagator,
		ConfigProperties configProperties) {
	return TextMapPropagator.composite(W3CTraceContextPropagator.getInstance(),HeaderPassthroughPropagator.getInstance());
}

[avcad]

Thank you. I ended up changing the code to use ConfigurablePropagatorProvider, and I will require that the new provider be set with OTEL_PROPAGATORS. Not ideal but works