multiple propagation headers: B3 and W3C

[ffatghub]

Hi all, I am new to otel please bear with me,

in case of manual instrumentation is it possible to use 2 propagators for getting (extract) and setting (inject) both B3 and W3C headers? Something similar to - if I understand it right - what can be achieved with "-Dotel.propagators=tracecontext,baggage,b3multi" and javaagent.

thanks a lot

[jkwatson]

See the docs here for how to assign multiple propagators: https://opentelemetry.io/docs/instrumentation/java/manual/#setup

[ffatghub]

See the docs here for how to assign multiple propagators: https://opentelemetry.io/docs/instrumentation/java/manual/#setup

Hi @jkwatson , thanks. You mean something like this?

        return OpenTelemetrySdk.builder()
                .setTracerProvider(sdkTracerProvider)
                .setMeterProvider(sdkMeterProvider)
                .setPropagators(ContextPropagators.create(B3Propagator.injectingMultiHeaders()))
                .setPropagators(ContextPropagators.create(W3CTraceContextPropagator.getInstance()))
                .buildAndRegisterGlobal();

How OTEL decide which propagator to use for outbound HTTP requests (inject time)?

thank you

[jkwatson]

See the docs here for how to assign multiple propagators: https://opentelemetry.io/docs/instrumentation/java/manual/#setup

Hi @jkwatson , thanks. You mean something like this?

        return OpenTelemetrySdk.builder()
                .setTracerProvider(sdkTracerProvider)
                .setMeterProvider(sdkMeterProvider)
                .setPropagators(ContextPropagators.create(B3Propagator.injectingMultiHeaders()))
                .setPropagators(ContextPropagators.create(W3CTraceContextPropagator.getInstance()))
                .buildAndRegisterGlobal();

How OTEL decide which propagator to use for outbound HTTP requests (inject time)?

thank you

Context propagators.create(...) takes vararg parameters.

It will inject all of the headers from all of the configured propagators.

[ffatghub]

W3CTraceContextPropagator.getInstance()

Hi @jkwatson , create() in opentelemetry-sdk.1.19.0.jar takes - if I had enough coffee :-) - one argument.

static ContextPropagators create(TextMapPropagator textPropagator) {
        Objects.requireNonNull(textPropagator, "textPropagator");
        return new DefaultContextPropagators(textPropagator);
}

ciao thanks

[jkwatson]

W3CTraceContextPropagator.getInstance()

Hi @jkwatson , create() in opentelemetry-sdk.1.19.0.jar takes - if I had enough coffee :-) - one argument.

static ContextPropagators create(TextMapPropagator textPropagator) {

        Objects.requireNonNull(textPropagator, "textPropagator");

        return new DefaultContextPropagators(textPropagator);

}

ciao thanks

Sorry, I misremembered. It's TextMapPropagator.composite(...)

[ffatghub]

        return OpenTelemetrySdk.builder()
                .setTracerProvider(sdkTracerProvider)
                .setMeterProvider(sdkMeterProvider)
                .setPropagators(ContextPropagators.create(
                        TextMapPropagator.composite(
                                B3Propagator.injectingMultiHeaders(),
                                W3CTraceContextPropagator.getInstance())))
                .buildAndRegisterGlobal();

thanks

[jkwatson]

I'm going to turn this into a discussion, since it's not an issue.