Append correlation id to every log java

Question

I need to append correlation id to logs from every request I get.

Here is my filter. It works good until I get to async block like runAsync().

I read about MDC and how it use ThreadLocal but can't understand how to use it in async because it uses ForkJoinPool.

@Component
public class Slf4jFilter extends OncePerRequestFilter {

private static final String CORRELATION_ID_HEADER_NAME = "correlation-id";
private static final String CORRELATION_ID_LOG_VAR_NAME = "correlationId";

@Override
protected void doFilterInternal(HttpServletRequest request,
    HttpServletResponse response, FilterChain chain)
throws ServletException, IOException {
    try {
        ofNullable(request.getHeader(CORRELATION_ID_HEADER_NAME)).ifPresent(correlationId -> MDC
            .put(CORRELATION_ID_LOG_VAR_NAME, correlationId));
        chain.doFilter(request, response);
    }finally {
        removeCorrelationId();
    }
}

protected void removeCorrelationId() {
    MDC.remove(CORRELATION_ID_LOG_VAR_NAME);
}
}

logback.xml

<configuration>
<appender name="stdout" class="ch.qos.logback.core.ConsoleAppender">
    <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
        <pattern>%d{dd-MM-yyyy HH:mm:ss.SSS} [%thread %X{correlationId}] %-5level %logger{36} - %msg %n</pattern>
    </encoder>
</appender>
<root level="INFO">
    <appender-ref ref="stdout" />
</root>

Answer 1

Here's the solution I ended up. Thanks to @M.Prokhorov

Create a class called MdcRetention inside your project.

public final class MdcRetention {

public static Runnable wrap(final Runnable delegate) {
    return new MdcRetainingRunnable() {
        @Override
        protected void runInContext() {
            delegate.run();
        }
    };
}

private static abstract class MdcRetentionSupport {
    protected final Map<String, String> originalMdc;

    protected MdcRetentionSupport() {
        Map<String, String> originalMdc = MDC.getCopyOfContextMap();
        this.originalMdc = originalMdc == null ? Collections.emptyMap() : originalMdc;
    }
}

public static abstract class MdcRetainingRunnable extends MdcRetentionSupport implements Runnable {

    @Override
    public final void run() {
        Map<String, String> currentMdc = MDC.getCopyOfContextMap();
        MDC.setContextMap(originalMdc);
        try {
            runInContext();
        } finally {
            MDC.setContextMap(currentMdc);
        }
    }

    abstract protected void runInContext();
}}

Then wrap your Runnable inside runAsync() block using static method MdcRetention.wrap()

Before: runAsync(() -> someMethod());

After: runAsync(wrap(() -> someMethod()));