[Bug] I found an error while using the skywalking agent and a custom Java agent

[yasuo-deng]

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• I had searched in the issues and found no similar issues.

Apache SkyWalking Component

OAP server (apache/skywalking)

What happened

，

My application logback configuration:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration>
<configuration>
    <appender name="kafkaAppender" class="net.trueland.logback.KafkaAppender">
        <encoder charset="UTF-8" class="net.logstash.logback.encoder.LogstashEncoder">
            <provider class="org.apache.skywalking.apm.toolkit.log.logback.v1.x.logstash.TraceIdJsonProvider"/>
            <customFields>{"appname":"log-cdp-tag","version":"v-20241119"}</customFields>
            <includeMdc>true</includeMdc>
            <includeContext>true</includeContext>
            <throwableConverter class="net.logstash.logback.stacktrace.ShortenedThrowableConverter">
                <maxDepthPerThrowable>30</maxDepthPerThrowable>
                <rootCauseFirst>true</rootCauseFirst>
            </throwableConverter>
        </encoder>
        <topic>log-growth-cdp</topic>
        <keyingStrategy class="net.trueland.logback.keying.HostNameKeyingStrategy"/>
        <deliveryStrategy class="net.trueland.logback.delivery.AsynchronousDeliveryStrategy"/>
        <producerConfig>bootstrap.servers=kafka1:9092</producerConfig>
        <!-- don't wait for a broker to ack the reception of a batch.  -->
        <producerConfig>acks=0</producerConfig>
        <!-- wait up to 1000ms and collect log messages before sending them as a batch -->
        <producerConfig>linger.ms=1000</producerConfig>
        <!-- even if the producer buffer runs full, do not block the application but start to drop messages -->
        <!--<producerConfig>max.block.ms=0</producerConfig>-->
        <producerConfig>block.on.buffer.full=false</producerConfig>
    </appender>
    <include resource="org/springframework/boot/logging/logback/base.xml"/>
    <root level="INFO">
        <appender-ref ref="kafkaAppender"/>
    </root>
</configuration>

What you expected to happen

It should be normal without any errors, and when I access my application interface, the interface will report that the traceId corresponding to skywalking is set to the requestId in ResponseMessage

How to reproduce

The command I executed is as follows java -Xms3072m -Xmx3072m -javaagent:/sky/agent/skywalking-agent.jar -javaagent:/tracing/agent/trace-agent.jar -Dskywalking.agent.is_cache_enhanced_class=true -Dskywalking.agent.class_cache_mode=MEMORY -Dskywalking.agent.service_name=cdp-tag -Dskywalking.collector.backend_service=192.168.245.88:11800 -jar /tmp/app.jar，The skywaling version is 8.7.0, with error messages

Anything else

Customize agent code:

import net.bytebuddy.asm.Advice;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.dynamic.DynamicType;
import net.bytebuddy.matcher.ElementMatchers;
import net.bytebuddy.utility.JavaModule;

import java.lang.instrument.Instrumentation;
import java.security.ProtectionDomain;
import java.util.logging.Level;
import java.util.logging.Logger;


public class LoggingAgent {

    private static final Logger logger = Logger.getLogger(LoggingAgent.class.getName());
    private static boolean premainCalled = false;

    public static void premain(String agentArgs, Instrumentation inst) {
        if (premainCalled) {
            logger.log(Level.INFO, "agentmain method has already been called, skipping.");
            return;
        }
        premainCalled = true;
        try {
            new AgentBuilder.Default()
                    .type(ElementMatchers.nameStartsWith("net.trueland.cdp.tag.controller"))
                    .transform(new AgentBuilder.Transformer() {
                        @Override
                        public DynamicType.Builder<?> transform(
                                DynamicType.Builder<?> builder,
                                TypeDescription typeDescription,
                                ClassLoader classLoader,
                                JavaModule module,
                                ProtectionDomain protectionDomain
                        ) {
                            return builder.method(ElementMatchers.returns(net.trueland.common.ResponseMessage.class))
                                    .intercept(Advice.to(ResponseInterceptor.class));
                        }
                    })
                    .with(new AgentBuilder.Listener.Adapter() {
                        @Override
                        public void onError(String typeName, ClassLoader classLoader, JavaModule module, boolean loaded, Throwable throwable) {
                            logger.log(Level.SEVERE, "处理类 {0} 时出错: {1}", new Object[]{typeName, throwable.getMessage()});
                        }
                    })
                    .installOn(inst);
        } catch (Exception e) {
            logger.log(Level.INFO, "Java Agent 初始化失败: {0}", e.getMessage());
            e.printStackTrace();
        }

        logger.log(Level.INFO, "Java Trace Agent initialized.");
    }
}

import net.bytebuddy.asm.Advice;
import net.trueland.common.ResponseMessage;
import org.apache.skywalking.apm.toolkit.trace.TraceContext;

public class ResponseInterceptor {

    @Advice.OnMethodExit(onThrowable = Throwable.class)
    public static void intercept(@Advice.Return(readOnly = false) ResponseMessage<?> returnValue, @Advice.Origin Class<?> originClass) {
        try {
            if (returnValue == null) {
                return;
            }
            String traceId = TraceContext.traceId();
            returnValue.setRequestId(traceId);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}```

### Are you willing to submit a pull request to fix on your own?

- [ ] Yes I am willing to submit a pull request on my own!

### Code of Conduct

- [x] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

[wu-sheng]

At least pick latest skywalking, 8.7 is a very old version, years ago.

[yasuo-deng]

Do I have to develop in Skywalking Java? Also, after developing, just send a jar package and put it under skywaling/plugins/. I don't want to submit the PR yet, let's test it ourselves

[wu-sheng]

What do you mean? I am confused. This is just a source code, you could do anything you prefer by following APLv2. We don't ask for pull requests of your private codes.

[yasuo-deng]

My code has been submitted here, https://github.com/yasuo-deng/skywalking-java/tree/8.8.0-dxy Then I packed it and put it in the plugins directory of the agent, but in reality, the expected results did not appear. How can I debug it? Please help me take a look

[wu-sheng]

Sorry. I would not have the time and energy to do that. It is hard to judge which codes I should look into or shouldn't, so, in OSS, I have to said NO to every debug requirement.
OSS is a kind of collaboration, it is not a kind of service from me.

[yasuo-deng]

Okay, thank you very much. This is what I should do myself. I will find a way to see for myself

[yasuo-deng]

I used a custom plugin and encountered this error when accessing the Spring MVC interface. I don't know why this class cannot be redefined. The code structure is as follows:


I have printed this log multiple times in my application：Attempting to match classes with @controller or @RestController annotations.

[wu-sheng]

If the target is the same, yes.

[yasuo-deng]

If written in this project, is it necessary to modify the logic in RestMapping MethodInterceptor and not define other Instrumentation and Interceptors

[wu-sheng]

That is on your own. We don't have any opinion in a fork work.

[yasuo-deng]

I solved the problem by adding only a few lines of code. Thank you for your help

[yasuo-deng]

Is there an official WeChat group that you can add to facilitate future discussions

[wu-sheng]

No, we stay on GitHub, slack, mailing list.

[yasuo-deng]

I want to see the corresponding traceId in the MQ consumer, but in actual testing, it is not available. Is there any other way? My code configuration is all here

[yasuo-deng]

At present, in addition to Kafka, there are also Rabbit MQ logs, hoping to have TraceId