Fix entry and exit span methods bug.

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/context/TracingContext.java

@@ -77,10 +77,11 @@ public class TracingContext implements AbstractTracerContext {
 
     @Override
     public AbstractSpan createEntrySpan(final String operationName) {
+        AbstractTracingSpan entrySpan;
         AbstractTracingSpan parentSpan = peek();
         final int parentSpanId = parentSpan == null ? -1 : parentSpan.getSpanId();
         if (parentSpan == null) {
-            AbstractTracingSpan span = (AbstractTracingSpan)DictionaryManager.findOperationNameCodeSection()
+            entrySpan = (AbstractTracingSpan)DictionaryManager.findOperationNameCodeSection()
                 .find(segment.getApplicationId(), operationName)
                 .doInCondition(new PossibleFound.FoundAndObtain() {
                     @Override public Object doProcess(int operationId) {
@@ -91,9 +92,10 @@ public class TracingContext implements AbstractTracerContext {
                         return new EntrySpan(spanIdGenerator++, parentSpanId, operationName);
                     }
                 });
-            return push(span);
+            entrySpan.start();
+            return push(entrySpan);
         } else if (parentSpan.isEntry()) {
-            return parentSpan;
+            return parentSpan.start();
         } else {
             throw new IllegalStateException("The Entry Span can't be the child of Non-Entry Span");
         }
@@ -116,17 +118,19 @@ public class TracingContext implements AbstractTracerContext {
                     return new LocalSpan(spanIdGenerator++, parentSpanId, operationName);
                 }
             });
+        span.start();
         return push(span);
     }
 
     @Override
     public AbstractSpan createExitSpan(final String operationName, final String remotePeer) {
+        AbstractTracingSpan exitSpan;
         AbstractTracingSpan parentSpan = peek();
         if (parentSpan != null && parentSpan.isExit()) {
-            return parentSpan;
+            exitSpan = parentSpan;
         } else {
             final int parentSpanId = parentSpan == null ? -1 : parentSpan.getSpanId();
-            AbstractTracingSpan span = (AbstractTracingSpan)DictionaryManager.findApplicationCodeSection()
+            exitSpan = (AbstractTracingSpan)DictionaryManager.findApplicationCodeSection()
                 .find(remotePeer).doInCondition(
                     new PossibleFound.FoundAndObtain() {
                         @Override
@@ -153,8 +157,10 @@ public class TracingContext implements AbstractTracerContext {
                             return new ExitSpan(spanIdGenerator++, parentSpanId, operationName, remotePeer);
                         }
                     });
-            return push(span);
+            exitSpan.start();
+            push(exitSpan);
         }
+        return exitSpan;
     }
 
     @Override

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/context/trace/EntrySpan.java

 package org.skywalking.apm.agent.core.context.trace;
 
+import org.skywalking.apm.agent.core.dictionary.DictionaryUtil;
+import org.skywalking.apm.network.trace.component.Component;
+
 /**
  * The <code>EntrySpan</code> represents a service provider point, such as Tomcat server entrance.
  *
@@ -46,6 +49,33 @@ public class EntrySpan extends AbstractTracingSpan {
         return this;
     }
 
+    @Override
+    public AbstractSpan setLayer(SpanLayer layer) {
+        if (stackDepth == currentMaxDepth) {
+            return super.setLayer(layer);
+        } else {
+            return this;
+        }
+    }
+
+    @Override
+    public AbstractSpan setComponent(Component component) {
+        if (stackDepth == currentMaxDepth) {
+            return super.setComponent(component);
+        } else {
+            return this;
+        }
+    }
+
+    @Override
+    public AbstractSpan setComponent(String componentName) {
+        if (stackDepth == currentMaxDepth) {
+            return super.setComponent(componentName);
+        } else {
+            return this;
+        }
+    }
+
     @Override
     public boolean finish(TraceSegment owner) {
         if (--stackDepth == 0) {
@@ -74,6 +104,9 @@ public class EntrySpan extends AbstractTracingSpan {
     }
 
     private void clearWhenRestart() {
+        this.componentId = DictionaryUtil.nullValue();
+        this.componentName = null;
+        this.layer = null;
         this.logs = null;
         this.tags = null;
     }

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/context/trace/ExitSpan.java

 package org.skywalking.apm.agent.core.context.trace;
 
 import org.skywalking.apm.agent.core.dictionary.DictionaryUtil;
+import org.skywalking.apm.network.trace.component.Component;
 
 /**
  * The <code>ExitSpan</code> represents a service consumer point, such as Feign, Okhttp discovery for a Http service.
@@ -66,6 +67,33 @@ public class ExitSpan extends AbstractTracingSpan {
         }
     }
 
+    @Override
+    public AbstractSpan setLayer(SpanLayer layer) {
+        if (stackDepth == 1) {
+            return super.setLayer(layer);
+        } else {
+            return this;
+        }
+    }
+
+    @Override
+    public AbstractSpan setComponent(Component component) {
+        if (stackDepth == 1) {
+            return super.setComponent(component);
+        } else {
+            return this;
+        }
+    }
+
+    @Override
+    public AbstractSpan setComponent(String componentName) {
+        if (stackDepth == 1) {
+            return super.setComponent(componentName);
+        } else {
+            return this;
+        }
+    }
+
     @Override
     public ExitSpan log(Throwable t) {
         if (stackDepth == 1) {

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/context/trace/TraceSegmentRef.java

@@ -31,6 +31,11 @@ public class TraceSegmentRef {
      */
     private List<DistributedTraceId> distributedTraceIds;
 
+    /**
+     * Transform a {@link ContextCarrier} to the <code>TraceSegmentRef</code>
+     *
+     * @param carrier the valid cross-process propagation format.
+     */
     public TraceSegmentRef(ContextCarrier carrier) {
         this.traceSegmentId = carrier.getTraceSegmentId();
         this.spanId = carrier.getSpanId();