Why my interceptor never get executed ?

[OldFarmer86]

Hi, I am using bytebuddy 1.11.16 with OpneJDK 8

I want to intercept java.net.Socket, here is my code:

instrumentation:

AgentBuilder.Transformer methodsTransformer = new AgentBuilder.Transformer() {
	@Override
	public DynamicType.Builder<?> transform(DynamicType.Builder<?> builder, TypeDescription typeDescription, ClassLoader classLoader, JavaModule javaModule) {
		return builder.method(isPublic().and(not(isAbstract())).and(not(isDefaultMethod()))).intercept(MethodDelegation.to(SocketInterceptor.class));
	}
};

AgentBuilder.Listener listener = new AgentBuilder.Listener.WithErrorsOnly(
		new AgentBuilder.Listener.StreamWriting(new PrintStream(new LoggingOutputStream(log, LoggingOutputStream.LogLevel.ERROR))));

// ElementMatcher.Junction<NamedElement> startMatcher = any();

if (recorder == null) {
	recorder = "";
}

if (recorder.equals("default")) {
	log.info("using default in-memory recorder.");
	SocketInterceptor.recorder = new DefaultRecorder();
} else {
	log.info("using default in-memory recorder.");
	SocketInterceptor.recorder = new DefaultRecorder();
}



new AgentBuilder.Default().type(is(java.net.Socket.class))
		.transform(methodsTransformer).with(listener).installOn(inst);

interceptor:

@RuntimeType
public static Object interceptor(@Origin Class<?> clazz, @Origin Method method, @SuperCall Callable<?> callable, @net.bytebuddy.implementation.bind.annotation.This Object inst, @AllArguments Object[] args) throws Exception {
System.out.println("--------------------------------------->>> intercepting socket methods");

// this is equal to original method, will not cause inner calls to other
// matching methods get intercepted.
Object o = callable.call();
log.debug("intercepting {}#{}", clazz.getName(), method.getName());
int hashCode = System.identityHashCode(inst);
if (java.net.Socket.class.isAssignableFrom(clazz)) {
//			ConnectionInfo ci = recorder.getConnectionInfo(hashCode);
//			if (ci == null) {
//				log.trace("connection@{} is not in records, while intercepting {}#{}", hashCode, clazz.getName(), method.getName());
//			}

	if (method.getName().equals("connect")) {

		ConnectionInfo ci = new ConnectionInfo();
		ci.setHash(hashCode);
		ci.setCreationTime(System.currentTimeMillis());
		ci.setInstance((Socket) inst);
		String stackTrace = StringUtils.getCurrentThreadStackTrace();
		String shash = StringUtils.md5(stackTrace);
		ci.setStackHash(shash);

		log.info("connection@{} of type {} acquired by stack@{}", hashCode, method.getDeclaringClass().getName(), shash);
		log.debug(stackTrace);

		SocketMetrics.ACTIVE_CON.labels(SocketTracer.getConfig("app")).inc();
		SocketMetrics.TOTAL_CON.labels(SocketTracer.getConfig("app")).inc();
		Timer timer = SocketMetrics.CON_DURATION_TIME.labels(SocketTracer.getConfig("app"), Integer.toString(hashCode), shash).startTimer();

		conTimers.put(hashCode, timer);

		recorder.connectionCreated(ci, stackTrace);
	} else if (method.getName().equals("close")) {
		log.info("connection@{} released", hashCode);

		SocketMetrics.ACTIVE_CON.labels(SocketTracer.getConfig("app")).dec();
		SocketMetrics.TOTAL_CON_CLOSED.labels(SocketTracer.getConfig("app")).inc();
		conTimers.get(hashCode).observeDuration();
		conTimers.remove(hashCode);

		recorder.connectionClosed(hashCode);
	}

} else if (java.nio.channels.SocketChannel.class.isAssignableFrom(clazz)) {

}
return o;
}

any hint on this ?

[raphw]

Multiple problems:

1. Your class is already loaded, so you would need to retransform it. Register a RetransformationStrategy for this.
2. You need to adjust your ignore matcher. By default Byte Buddy ignores all JVM classes.
3. Method delegation needs to be able to see the inserted code. This won't work as bootstrap classes do not see your agent's code. Advice inlines code what does not imply this problem. (You will likely need to inject your helper classes into the boot loader.)