set a new interceptor point for log4j2 to output traceid.

skywalking-application-toolkit/skywalking-toolkit-log4j-2.x/src/main/java/com/a/eye/skywalking/toolkit/log4j/v2/x/Log4j2OutputAppender.java

+package com.a.eye.skywalking.toolkit.log4j.v2.x;
+
+/**
+ * Created by wusheng on 2016/12/11.
+ */
+public class Log4j2OutputAppender {
+    public static void append(StringBuilder toAppendTo){
+        toAppendTo.append("TID: N/A");
+    }
+}

skywalking-application-toolkit/skywalking-toolkit-log4j-2.x/src/main/java/com/a/eye/skywalking/toolkit/log4j/v2/x/TraceIdConverter.java

@@ -29,6 +29,6 @@ public class TraceIdConverter extends LogEventPatternConverter {
 
     @Override
     public void format(LogEvent event, StringBuilder toAppendTo) {
-        toAppendTo.append("TID: N/A");
+        Log4j2OutputAppender.append(toAppendTo);
     }
 }

skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/TraceIdConverterActivation.java → skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/Log4j2OutputAppenderActivation.java

 package com.a.eye.skywalking.toolkit.activation.log4j.v2.x;
 
-import com.a.eye.skywalking.plugin.interceptor.ConstructorInterceptPoint;
-import com.a.eye.skywalking.plugin.interceptor.InstanceMethodsInterceptPoint;
 import com.a.eye.skywalking.plugin.interceptor.MethodMatcher;
-import com.a.eye.skywalking.plugin.interceptor.enhance.ClassInstanceMethodsEnhancePluginDefine;
+import com.a.eye.skywalking.plugin.interceptor.StaticMethodsInterceptPoint;
+import com.a.eye.skywalking.plugin.interceptor.enhance.ClassStaticMethodsEnhancePluginDefine;
 import com.a.eye.skywalking.plugin.interceptor.matcher.SimpleMethodMatcher;
 
 /**
  * Created by wusheng on 2016/12/7.
  */
-public class TraceIdConverterActivation extends ClassInstanceMethodsEnhancePluginDefine {
+public class Log4j2OutputAppenderActivation extends ClassStaticMethodsEnhancePluginDefine {
     @Override
     protected String enhanceClassName() {
-        return "com.a.eye.skywalking.toolkit.log4j.v2.x.TraceIdConverter";
+        return "com.a.eye.skywalking.toolkit.log4j.v2.x.Log4j2OutputAppender";
     }
 
     @Override
-    protected ConstructorInterceptPoint[] getConstructorsInterceptPoints() {
-        return null;
-    }
-
-    @Override
-    protected InstanceMethodsInterceptPoint[] getInstanceMethodsInterceptPoints() {
-        return new InstanceMethodsInterceptPoint[]{new InstanceMethodsInterceptPoint() {
+    protected StaticMethodsInterceptPoint[] getStaticMethodsInterceptPoints() {
+        return new StaticMethodsInterceptPoint[]{new StaticMethodsInterceptPoint() {
             @Override
             public MethodMatcher[] getMethodsMatchers() {
-                return new MethodMatcher[]{new SimpleMethodMatcher("format")};
+                return new MethodMatcher[]{new SimpleMethodMatcher("append")};
             }
 
             @Override

skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/java/com/a/eye/skywalking/toolkit/activation/log4j/v2/x/PrintTraceIdInterceptor.java

@@ -2,16 +2,14 @@ package com.a.eye.skywalking.toolkit.activation.log4j.v2.x;
 
 import com.a.eye.skywalking.api.Tracing;
 import com.a.eye.skywalking.plugin.interceptor.EnhancedClassInstanceContext;
-import com.a.eye.skywalking.plugin.interceptor.enhance.InstanceMethodInvokeContext;
-import com.a.eye.skywalking.plugin.interceptor.enhance.InstanceMethodsAroundInterceptor;
-import com.a.eye.skywalking.plugin.interceptor.enhance.MethodInterceptResult;
+import com.a.eye.skywalking.plugin.interceptor.enhance.*;
 
 /**
  * Created by wusheng on 2016/12/7.
  */
-public class PrintTraceIdInterceptor implements InstanceMethodsAroundInterceptor {
+public class PrintTraceIdInterceptor implements StaticMethodsAroundInterceptor {
     @Override
-    public void beforeMethod(EnhancedClassInstanceContext context, InstanceMethodInvokeContext interceptorContext, MethodInterceptResult result) {
+    public void beforeMethod(StaticMethodInvokeContext interceptorContext, MethodInterceptResult result) {
         ((StringBuilder)interceptorContext.allArguments()[1]).append("TID:" + Tracing.getTraceId());
 
         //make sure origin method do not invoke.
@@ -19,12 +17,12 @@ public class PrintTraceIdInterceptor implements InstanceMethodsAroundInterceptor
     }
 
     @Override
-    public Object afterMethod(EnhancedClassInstanceContext context, InstanceMethodInvokeContext interceptorContext, Object ret) {
-        return ret;
+    public Object afterMethod(StaticMethodInvokeContext interceptorContext, Object ret) {
+        return null;
     }
 
     @Override
-    public void handleMethodException(Throwable t, EnhancedClassInstanceContext context, InstanceMethodInvokeContext interceptorContext) {
+    public void handleMethodException(Throwable t, MethodInvokeContext interceptorContext) {
 
     }
 }

skywalking-sniffer/skywalking-toolkit-activation/skywalking-toolkit-log4j-2.x-activation/src/main/resources/skywalking-plugin.def

-com.a.eye.skywalking.toolkit.activation.log4j.v2.x.TraceIdConverterActivation
+com.a.eye.skywalking.toolkit.activation.log4j.v2.x.Log4j2OutputAppenderActivation