Best way to pass custom headers along with Sleuth X-B3* headers

Question

As per the README here , I am using the following configuration to pass x-vcap-request-id and x-vcap-group-id from one application to the other.

@Bean
public Factory propagationFactory() {
    return brave.propagation.ExtraFieldPropagation.newFactory(brave.propagation.B3Propagation.FACTORY,
            "x-vcap-request-id", "x-vcap-group-id");
}

@Bean
public TracingFactoryBean tracing() {
    TracingFactoryBean tracingFactoryBean = new TracingFactoryBean();
    tracingFactoryBean.setPropagationFactory(propagationFactory());
    return tracingFactoryBean;
}

However, this configuration is messing up default sleuth behavior. With this code, Sleuth no longer adds TraceId and SpanId to the log

What's the best/recommended way to pass along custom headers between microservices ?

Answer 1

If you read the docs on prefixed fields you'll see the following section

A difference from previous versions of Sleuth is that, with Brave, you must pass the list of baggage keys. There are two properties to achieve this. With the spring.sleuth.baggage-keys, you set keys that get prefixed with baggage- for HTTP calls and baggage_ for messaging. You can also use the spring.sleuth.propagation-keys property to pass a list of prefixed keys that are whitelisted without any prefix.

Just set the properties and things will work out of the box. It's always good to read the project documentation.