Spring Boot 3 context propagation using micrometer does not work

Question

We have a microservices architecture and are trying to implement distributed tracing, with the below somewhat naive implementation:

I've got the following dependencies for micrometer and reactor:

    <dependency>
        <groupId>io.micrometer</groupId>
        <artifactId>micrometer-observation</artifactId>
    </dependency>
    <dependency>
        <groupId>io.micrometer</groupId>
        <artifactId>micrometer-tracing-bridge-brave</artifactId>
    </dependency>
    <dependency>
        <groupId>io.projectreactor</groupId>
        <artifactId>reactor-core</artifactId>
    </dependency>

We generate a unique correlation id and store it in ThreadContext:

@Component
@RequiredArgsConstructor
@Log4j2
public class CorrelationIdFilter extends OncePerRequestFilter {

  public static final String X_CORRELATION_ID = "X-Correlation-Id";

  @Override
  protected void doFilterInternal(
      HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
      throws ServletException, IOException {

    String correlationId = request.getHeader(X_CORRELATION_ID);
    if (Objects.isNull(correlationId)) {
      correlationId = UUID.randomUUID().toString().split("-")[0];
      log.info(
          "Request does not include {} header. Generated value '{}'",
          X_CORRELATION_ID,
          correlationId);
    }

    ThreadContext.put(X_CORRELATION_ID, correlationId);

    try {
      filterChain.doFilter(request, response);
    } finally {
      threadContextFacade.remove(X_CORRELATION_ID);
    }
  }

Adding new X_CORRELATION_ID to log4j2.xml:

%d{yyyy-MM-dd HH:mm:ss.SSS} %5p ${hostName} -- cId:%X{X-Correlation-Id} [%15.15t] %-40.40c{1.} : %m%n%ex

This all works like a treat, I can see correlation id in the logs.

Now I need to propagate this correlation-id to downstream service.

For that, I've added the following in the main metod of the Spring boot application:

  public static void main(String[] args) {
    Hooks.enableAutomaticContextPropagation();
    SpringApplication.run(CompanyApplication.class, args);
  }

But the downstream application never receives X-Correlation-Id header.

What am I missing?

Spring Boot 3 context propagation using micrometer does not work

0 Answers0