fix issue that open tracing activation set tag failed

apm-application-toolkit/apm-toolkit-opentracing/src/main/java/org/skywalking/apm/toolkit/opentracing/SkywalkingSpan.java

@@ -68,16 +68,19 @@ public class SkywalkingSpan implements Span {
         return SkywalkingContext.INSTANCE;
     }
 
+    @NeedSnifferActivation(
+        "1. ContextManager#activeSpan()" +
+            "2. SkywalkingSpan#setTag(String, String)")
     @Override public Span setTag(String key, String value) {
-        return null;
+        return this;
     }
 
     @Override public Span setTag(String key, boolean value) {
-        return null;
+        return setTag(key, String.valueOf(value));
     }
 
     @Override public Span setTag(String key, Number value) {
-        return null;
+        return setTag(key, String.valueOf(value));
     }
 
     @Override

apm-sniffer/apm-toolkit-activation/apm-toolkit-opentracing-activation/src/main/java/org/skywalking/apm/toolkit/activation/opentracing/span/SkywalkingSpanActivation.java

@@ -48,6 +48,7 @@ public class SkywalkingSpanActivation extends ClassInstanceMethodsEnhancePluginD
     private static final String FINISH_METHOD_INTERCEPTOR = "org.skywalking.apm.toolkit.activation.opentracing.span.SpanFinishInterceptor";
     private static final String LOG_INTERCEPTOR = "org.skywalking.apm.toolkit.activation.opentracing.span.SpanLogInterceptor";
     private static final String SET_OPERATION_NAME_INTERCEPTOR = "org.skywalking.apm.toolkit.activation.opentracing.span.SpanSetOperationNameInterceptor";
+    private static final String SET_TAG_INTERCEPTOR = "org.skywalking.apm.toolkit.activation.opentracing.span.SpanSetTagInterceptor";
 
     @Override
     protected ClassMatch enhanceClass() {
@@ -132,6 +133,19 @@ public class SkywalkingSpanActivation extends ClassInstanceMethodsEnhancePluginD
                 public boolean isOverrideArgs() {
                     return false;
                 }
+            },
+            new InstanceMethodsInterceptPoint() {
+                @Override public ElementMatcher<MethodDescription> getMethodsMatcher() {
+                    return named("setTag").and(takesArgument(0, String.class)).and(takesArgument(1, String.class));
+                }
+
+                @Override public String getMethodsInterceptor() {
+                    return SET_TAG_INTERCEPTOR;
+                }
+
+                @Override public boolean isOverrideArgs() {
+                    return false;
+                }
             }
         };
     }

apm-sniffer/apm-toolkit-activation/apm-toolkit-opentracing-activation/src/main/java/org/skywalking/apm/toolkit/activation/opentracing/span/SpanSetTagInterceptor.java

@@ -0,0 +1,37 @@
+package org.skywalking.apm.toolkit.activation.opentracing.span;
+
+import io.opentracing.tag.Tags;
+import org.skywalking.apm.agent.core.context.ContextManager;
+import org.skywalking.apm.agent.core.context.trace.AbstractSpan;
+import org.skywalking.apm.agent.core.plugin.interceptor.enhance.EnhancedInstance;
+import org.skywalking.apm.agent.core.plugin.interceptor.enhance.InstanceMethodsAroundInterceptor;
+import org.skywalking.apm.agent.core.plugin.interceptor.enhance.MethodInterceptResult;
+
+public class SpanSetTagInterceptor implements InstanceMethodsAroundInterceptor {
+    @Override
+    public void beforeMethod(EnhancedInstance objInst, String methodName, Object[] allArguments,
+        Class<?>[] argumentsTypes, MethodInterceptResult result) throws Throwable {
+    }
+
+    @Override
+    public Object afterMethod(EnhancedInstance objInst, String methodName, Object[] allArguments,
+        Class<?>[] argumentsTypes, Object ret) throws Throwable {
+        AbstractSpan activeSpan = ContextManager.activeSpan();
+        String tagKey = String.valueOf(allArguments[0]);
+        String tagValue = String.valueOf(allArguments[1]);
+        if (Tags.COMPONENT.getKey().equals(tagKey)) {
+            activeSpan.setComponent(tagValue);
+        } else if (Tags.PEER_SERVICE.getKey().equals(tagKey)) {
+            activeSpan.setOperationName(tagValue);
+        } else {
+            activeSpan.tag(tagKey, tagValue);
+        }
+        return ret;
+    }
+
+    @Override
+    public void handleMethodException(EnhancedInstance objInst, String methodName, Object[] allArguments,
+        Class<?>[] argumentsTypes, Throwable t) {
+
+    }
+}