How to instrument java.net.Socket?

[rahjesh-vunet]

I have a requirement to create spans for the java.net.Socket calls to the backend from a Spring REST API. I tried to create an extension for this. I have creates the InstrumentationModule, Instrumentation and IgnoredTypesConfigurer.

// SocketInstrumentationModule.java
package instrumentation;

import static java.util.Collections.singletonList;

import java.util.List;
import java.util.logging.Logger;

import com.google.auto.service.AutoService;

import io.opentelemetry.javaagent.extension.instrumentation.InstrumentationModule;
import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;

@AutoService(InstrumentationModule.class)
public final class SocketInstrumentationModule extends InstrumentationModule {
	
	private static Logger logger = Logger.getLogger(SocketInstrumentationModule.class.getName());

	public SocketInstrumentationModule() {
		super("SocketInstrumentation");
		logger.info("SocketInstrumentationModule activated....");
	}

	@Override
	public List<TypeInstrumentation> typeInstrumentations() {
		return singletonList(new SocketInstrumentation());
	}

	@Override
	public boolean isHelperClass(String className) {
		return className.matches("java.net.Socket");
	}
}

// SocketInstrumentation.java
package instrumentation;

import static net.bytebuddy.matcher.ElementMatchers.any;

import java.util.logging.Logger;

import io.opentelemetry.api.GlobalOpenTelemetry;
import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.StatusCode;
import io.opentelemetry.api.trace.Tracer;
import io.opentelemetry.context.Context;
import io.opentelemetry.context.Scope;
import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
import net.bytebuddy.asm.Advice;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.matcher.ElementMatcher;
import net.bytebuddy.matcher.ElementMatchers;
public class SocketInstrumentation implements TypeInstrumentation {

private static Logger logger = Logger.getLogger(SocketInstrumentation.class.getName());

@Override
public ElementMatcher<TypeDescription> typeMatcher() {
	logger.info("Entering typeMatcher");
	return ElementMatchers.named("java.net.Socket");
}

@Override
public void transform(TypeTransformer typeTransformer) {
	logger.info("Entering transform...");
	typeTransformer.applyAdviceToMethod(any(), this.getClass().getName() + "$SocketPoolAdvice");
}

public static class SocketPoolAdvice {
	@Advice.OnMethodEnter(suppress = Throwable.class)
	public static Scope onEnter(@Advice.Local("otelSpan") Span span, @Advice.Local("otelContext") Context context) {

		logger.info("Entering method");

		Tracer tracer = GlobalOpenTelemetry.getTracer("java.net.socket.instrumentation", "1.0.0");

		span = tracer.spanBuilder("mySpan").startSpan();

		Scope scope = span.makeCurrent();

		return scope;

	}

	@Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
	public static void onExit(@Advice.Thrown Throwable throwable, @Advice.Local("otelSpan") Span span,
			@Advice.Enter Scope scope) {
		scope.close();

		if (throwable != null) {
			span.setStatus(StatusCode.ERROR, "Exception thrown in method");
		}

		span.end();
	}
}
}

//SocketIgnoredTypesConfigurer.java
package instrumentation;

import java.util.logging.Logger;

import com.google.auto.service.AutoService;
import io.opentelemetry.javaagent.extension.ignore.IgnoredTypesBuilder;
import io.opentelemetry.javaagent.extension.ignore.IgnoredTypesConfigurer;
import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;

@autoservice(IgnoredTypesConfigurer.class)
public class SocketIgnoredTypesConfigurer implements IgnoredTypesConfigurer {

private static Logger logger = Logger.getLogger(SocketIgnoredTypesConfigurer.class.getName());

@Override
public void configure(IgnoredTypesBuilder builder, ConfigProperties config) {
	logger.info(" Allowing class java.net.Socket...");
	builder.allowClass("java.net.Socket");
}
}

I build this using maven abd create the jar. I am instrumenting my Spring REST API application using the javaagent and this extension.

-javaagent:../../assets/opentelemetry-javaagent-1.32.0.jar -Dotel.javaagent.extensions=../../extension/SocketInstrumentation/target/socket-instrumentation-1.0.jar

I could see the logs that prints the log messages in the extension I created.

[otel.javaagent 2023-12-06 00:59:03:887 +0530] [main] INFO io.opentelemetry.javaagent.tooling.VersionLogger - opentelemetry-javaagent - version: 1.32.0
[otel.javaagent 2023-12-06 00:59:04:534 +0530] [main] INFO instrumentation.SocketIgnoredTypesConfigurer - Allowing class java.net.Socket...
[otel.javaagent 2023-12-06 00:59:04:646 +0530] [main] INFO instrumentation.SocketInstrumentationModule - SocketInstrumentationModule activated....
[otel.javaagent 2023-12-06 00:59:05:097 +0530] [main] INFO instrumentation.SocketInstrumentation - Entering typeMatcher
[otel.javaagent 2023-12-06 00:59:05:097 +0530] [main] INFO instrumentation.SocketInstrumentation - Entering transform...

But the OnMethodEnter and OnMethodExit advices are not called. I don't see the logs which were inside these methods.

My expectation was that calls to any method in java.net.Socket classes should result in creating the span.

Am I missing anything?

[taralshah007]

Can you share your git repo?

[steverao]

The problem has been solved #10008