How to get MDC after sending it from Tomcat thread to hystrix thread?

[aditya3234]

I have a class A which runs on tomcat thread. Class B is inside a jar which is a dependency of the project which has class A. Class B is running on hystrix thread. I have implemented a CustomConcurrency strategy and a custom Hystrix hook which puts the MDC from class A in class B.

The logs which are getting printed on class B show the MDC which I put in HystrixHook but when I print MDC.get("id") from Class B, it shows nothing.

I have implemented the concurrency strategy and hystrixhook using this link.

CustomConcurrency.java

public class ThreadLocalUtil {
    private static ThreadLocal<String> idTL = new ThreadLocal<>();

    public static void setId(String id) {
        idTL.set(id);
    }

    public static void getId() {
        return idTL.get();
    }

    public static void clear() {
        idTL.remove();
    }
}

public class ConcurrencyStrategy extends HystrixConcurrencyStrategy {
    @Override
    public <T> Callable<T> wrapCallable(Callable<T> callable) {
        String id = ThreadLocalUtil.getId(); 
        return () -> {
            try{
                ThreadLocalUtil.setId(id); 
                return callable.call();
            } 
            finally { 
                ThreadLocalUtil.clear() 
                } 
        };
    }
}

// Register the concurrency strategy
HystrixPlugins.getInstance().registerConcurrencyStrategy(new ConcurrencyStrategy());

HystrixHook.java

public class HystrixHook extends HystrixCommandExecutionHook {

    private String id;

    @Override
    public <T> void onStart(HystrixInvokable<T> commandInstance) {
        HystrixRequestContext.initializeContext();
        getThreadLocals();
    }

    @Override
    public <T> void onExecutionStart(HystrixInvokable<T> commandInstance) {
        setThreadLocals();
        MDC.put("id",id);
    }

    @Override
    public <T> void onFallbackStart(HystrixInvokable<T> commandInstance) {
        setThreadLocals();
        MDC.put("id",id);
    }

    @Override
    public <T> void onSuccess(HystrixInvokable<T> commandInstance) {
        HystrixRequestContext.getContextForCurrentThread().shutdown();
        super.onSuccess(commandInstance);
    }

    @Override
    public <T> Exception onError(HystrixInvokable<T> commandInstance, HystrixRuntimeException.FailureType failureType, Exception e) {
        HystrixRequestContext.getContextForCurrentThread().shutdown();
        return super.onError(commandInstance, failureType, e);
    }

    private void getThreadLocals() {
        id = ThreadLocalUtil.getId();
    }

    private void setThreadLocals() {
        ThreadLocalUtil.setId(id);
    }
}

// Register hystrix hook plugin
HystrixPlugins.getInstance().registerCommandExecutionHook(new HystrixHook());

[aditya3234]

Resolved.