Spring Cloud Sleuth: Initialise baggage item - spring-cloud-sleuth

Question

I already have this Java Configuration:
#Configuration
public class FAPIAutoConfiguration {
private static final String INTERACTION_ID = "x-fapi-interaction-id";
private final BaggageField fapiBaggageField = BaggageField.create(INTERACTION_ID);
#Bean
BaggagePropagationCustomizer baggagePropagationCustomizer() {
return builder -> builder.add(SingleBaggageField.
remote(fapiBaggageField));
}
#Bean
CorrelationScopeCustomizer correlationScopeCustomizer() {
return builder -> builder.add(SingleCorrelationField.create(fapiBaggageField));
}
}
And the propagation in a Webflux application works, but I would like to know what is the best way to initialize the baggage if it is not present in the request headers. I mean, if the header is missing, generate a value and propagate this one.

Answer 1

I ended up adding a TracingCustomizer to the above configuration to fill the value when is missing in that context.
#Bean
TracingCustomizer tracingCustomizer(UniqueIdGenerator generator) {
return builder -> builder.addSpanHandler(new SpanHandler() {
#Override
public boolean begin(TraceContext context, MutableSpan span, TraceContext parent) {
var value = fapiBaggageField.getValue(context);
if (value == null) {
fapiBaggageField.updateValue(context, generator.next());
}
return super.begin(context, span, parent);
}
});
}
I do not know if this is the best option yet