support span amount control mechanism

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

@@ -27,6 +27,7 @@ import org.skywalking.apm.agent.core.context.trace.AbstractTracingSpan;
 import org.skywalking.apm.agent.core.context.trace.EntrySpan;
 import org.skywalking.apm.agent.core.context.trace.ExitSpan;
 import org.skywalking.apm.agent.core.context.trace.LocalSpan;
+import org.skywalking.apm.agent.core.context.trace.NoopExitSpan;
 import org.skywalking.apm.agent.core.context.trace.NoopSpan;
 import org.skywalking.apm.agent.core.context.trace.TraceSegment;
 import org.skywalking.apm.agent.core.context.trace.TraceSegmentRef;
@@ -95,17 +96,28 @@ public class TracingContext implements AbstractTracerContext {
         if (!span.isExit()) {
             throw new IllegalStateException("Inject can be done only in Exit Span");
         }
-        ExitSpan exitSpan = (ExitSpan)span;
+
+        String peer;
+        int peerId;
+        if (span instanceof NoopExitSpan) {
+            NoopExitSpan exitSpan = (NoopExitSpan)span;
+            peerId = exitSpan.getPeerId();
+            peer = exitSpan.getPeer();
+        } else {
+            ExitSpan exitSpan = (ExitSpan)span;
+            peerId = exitSpan.getPeerId();
+            peer = exitSpan.getPeer();
+        }
 
         carrier.setTraceSegmentId(this.segment.getTraceSegmentId());
         carrier.setSpanId(span.getSpanId());
 
         carrier.setParentApplicationInstanceId(segment.getApplicationInstanceId());
 
-        if (DictionaryUtil.isNull(exitSpan.getPeerId())) {
-            carrier.setPeerHost(exitSpan.getPeer());
+        if (DictionaryUtil.isNull(peerId)) {
+            carrier.setPeerHost(peer);
         } else {
-            carrier.setPeerId(exitSpan.getPeerId());
+            carrier.setPeerId(peerId);
         }
         List<TraceSegmentRef> refs = this.segment.getRefs();
         int operationId;
@@ -304,21 +316,21 @@ public class TracingContext implements AbstractTracerContext {
      */
     @Override
     public AbstractSpan createExitSpan(final String operationName, final String remotePeer) {
-        if (isLimitMechanismWorking()) {
-            NoopSpan span = new NoopSpan();
-            return push(span);
-        }
         AbstractSpan exitSpan;
         AbstractSpan parentSpan = peek();
         if (parentSpan != null && parentSpan.isExit()) {
             exitSpan = parentSpan;
         } else {
             final int parentSpanId = parentSpan == null ? -1 : parentSpan.getSpanId();
-            exitSpan = (AbstractTracingSpan)DictionaryManager.findApplicationCodeSection()
+            exitSpan = (AbstractSpan)DictionaryManager.findApplicationCodeSection()
                 .find(remotePeer).doInCondition(
                     new PossibleFound.FoundAndObtain() {
                         @Override
                         public Object doProcess(final int peerId) {
+                            if (isLimitMechanismWorking()) {
+                                return new NoopExitSpan(peerId);
+                            }
+
                             return DictionaryManager.findOperationNameCodeSection()
                                 .findOnly(segment.getApplicationId(), operationName)
                                 .doInCondition(
@@ -338,6 +350,10 @@ public class TracingContext implements AbstractTracerContext {
                     new PossibleFound.NotFoundAndObtain() {
                         @Override
                         public Object doProcess() {
+                            if (isLimitMechanismWorking()) {
+                                return new NoopExitSpan(remotePeer);
+                            }
+
                             return DictionaryManager.findOperationNameCodeSection()
                                 .findOnly(segment.getApplicationId(), operationName)
                                 .doInCondition(
@@ -489,6 +505,6 @@ public class TracingContext implements AbstractTracerContext {
     }
 
     private boolean isLimitMechanismWorking() {
-        return spanIdGenerator > Config.Agent.SPAN_LIMIT_PER_SEGMENT;
+        return spanIdGenerator >= Config.Agent.SPAN_LIMIT_PER_SEGMENT;
     }
 }

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

+/*
+ * Copyright 2017, OpenSkywalking Organization All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Project repository: https://github.com/OpenSkywalking/skywalking
+ */
+
+package org.skywalking.apm.agent.core.context.trace;
+
+/**
+ * The <code>AbstractNoopSpan</code> represents a span implementation without any actual operation.
+ *
+ * @author zhangxin
+ */
+public interface AbstractNoopSpan extends AbstractSpan {
+}

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

+/*
+ * Copyright 2017, OpenSkywalking Organization All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Project repository: https://github.com/OpenSkywalking/skywalking
+ */
+
+package org.skywalking.apm.agent.core.context.trace;
+
+import java.util.Map;
+import org.skywalking.apm.network.trace.component.Component;
+
+public class NoopExitSpan implements AbstractNoopSpan {
+
+    private String peer;
+    private int peerId;
+
+    public NoopExitSpan(int peerId) {
+        this.peerId = peerId;
+    }
+
+    public NoopExitSpan(String peer) {
+        this.peer = peer;
+    }
+
+    @Override public AbstractSpan setComponent(Component component) {
+        return this;
+    }
+
+    @Override public AbstractSpan setComponent(String componentName) {
+        return this;
+    }
+
+    @Override public AbstractSpan setLayer(SpanLayer layer) {
+        return this;
+    }
+
+    @Override public AbstractSpan tag(String key, String value) {
+        return this;
+    }
+
+    @Override public AbstractSpan log(Throwable t) {
+        return this;
+    }
+
+    @Override public AbstractSpan errorOccurred() {
+        return null;
+    }
+
+    @Override public boolean isEntry() {
+        return false;
+    }
+
+    @Override public boolean isExit() {
+        return true;
+    }
+
+    @Override public AbstractSpan log(long timestamp, Map<String, ?> event) {
+        return this;
+    }
+
+    @Override public AbstractSpan setOperationName(String operationName) {
+        return this;
+    }
+
+    @Override public AbstractSpan start() {
+        return this;
+    }
+
+    @Override public int getSpanId() {
+        return 0;
+    }
+
+    @Override public int getOperationId() {
+        return 0;
+    }
+
+    @Override public String getOperationName() {
+        return "";
+    }
+
+    @Override public AbstractSpan setOperationId(int operationId) {
+        return this;
+    }
+
+    public int getPeerId() {
+        return peerId;
+    }
+
+    public String getPeer() {
+        return peer;
+    }
+}

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

@@ -29,7 +29,7 @@ import org.skywalking.apm.network.trace.component.Component;
  *
  * @author wusheng
  */
-public class NoopSpan implements AbstractSpan {
+public class NoopSpan implements AbstractNoopSpan {
     public NoopSpan() {
     }