Support v3 extension header

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

@@ -42,9 +42,11 @@ public class ContextCarrier implements Serializable {
     private String addressUsedAtClient;
 
     private CorrelationContext correlationContext = new CorrelationContext();
+    private ExtensionContext extensionContext = new ExtensionContext();
 
     public CarrierItem items() {
-        SW8CorrelationCarrierItem sw8CorrelationCarrierItem = new SW8CorrelationCarrierItem(correlationContext, null);
+        SW8ExtensionCarrierItem sw8ExtensionCarrierItem = new SW8ExtensionCarrierItem(extensionContext, null);
+        SW8CorrelationCarrierItem sw8CorrelationCarrierItem = new SW8CorrelationCarrierItem(correlationContext, sw8ExtensionCarrierItem);
         SW8CarrierItem sw8CarrierItem = new SW8CarrierItem(this, sw8CorrelationCarrierItem);
         return new CarrierItemHead(sw8CarrierItem);
     }

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

@@ -33,17 +33,20 @@ public class ContextSnapshot {
     private String parentEndpoint;
 
     private CorrelationContext correlationContext;
+    private ExtensionContext extensionContext;
 
     ContextSnapshot(String traceSegmentId,
                     int spanId,
                     DistributedTraceId primaryTraceId,
                     String parentEndpoint,
-                    CorrelationContext correlationContext) {
+                    CorrelationContext correlationContext,
+                    ExtensionContext extensionContext) {
         this.traceSegmentId = traceSegmentId;
         this.spanId = spanId;
         this.traceId = primaryTraceId;
         this.parentEndpoint = parentEndpoint;
         this.correlationContext = correlationContext.clone();
+        this.extensionContext = extensionContext.clone();
     }
 
     public boolean isFromCurrent() {

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

@@ -0,0 +1,100 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ *
+ */
+
+package org.apache.skywalking.apm.agent.core.context;
+
+import org.apache.skywalking.apm.agent.core.context.trace.AbstractSpan;
+
+import java.util.Objects;
+
+/**
+ * Extension context, It provides the interaction capabilities between the agents
+ * deployed in upstream and downstream services.
+ */
+public class ExtensionContext {
+
+    /**
+     * Tracing Mode. If true means represents all spans generated in this context should skip analysis.
+     */
+    private boolean skipAnalysis;
+
+    /**
+     * Serialize this {@link ExtensionContext} to a {@link String}
+     *
+     * @return the serialization string.
+     */
+    String serialize() {
+        return skipAnalysis ? "1" : "0";
+    }
+
+    /**
+     * Deserialize data from {@link String}
+     */
+    void deserialize(String value) {
+        this.skipAnalysis = Objects.equals(value, "1");
+    }
+
+    /**
+     * Prepare for the cross-process propagation.
+     */
+    void inject(ContextCarrier carrier) {
+        carrier.getExtensionContext().skipAnalysis = this.skipAnalysis;
+    }
+
+    /**
+     * Extra the {@link ContextCarrier#getExtensionContext()} into this context.
+     */
+    void extract(ContextCarrier carrier) {
+        this.skipAnalysis = carrier.getExtensionContext().skipAnalysis;
+    }
+
+    /**
+     * Handle the tracing span.
+     */
+    void handle(AbstractSpan span) {
+        if (this.skipAnalysis) {
+            span.skipAnalysis();
+        }
+    }
+
+    /**
+     * Clone the context data, work for capture to cross-thread.
+     */
+    public ExtensionContext clone() {
+        final ExtensionContext context = new ExtensionContext();
+        context.skipAnalysis = this.skipAnalysis;
+        return context;
+    }
+
+    void continued(ContextSnapshot snapshot) {
+        this.skipAnalysis = snapshot.getExtensionContext().skipAnalysis;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ExtensionContext that = (ExtensionContext) o;
+        return skipAnalysis == that.skipAnalysis;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(skipAnalysis);
+    }
+}

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

@@ -33,12 +33,14 @@ public class IgnoredTracerContext implements AbstractTracerContext {
     private static final NoopSpan NOOP_SPAN = new NoopSpan();
 
     private final CorrelationContext correlationContext;
+    private final ExtensionContext extensionContext;
 
     private int stackDepth;
 
     public IgnoredTracerContext() {
         this.stackDepth = 0;
         this.correlationContext = new CorrelationContext();
+        this.extensionContext = new ExtensionContext();
     }
 
     @Override
@@ -53,7 +55,7 @@ public void extract(ContextCarrier carrier) {
 
     @Override
     public ContextSnapshot capture() {
-        return new ContextSnapshot(null, -1, null, null, correlationContext);
+        return new ContextSnapshot(null, -1, null, null, correlationContext, extensionContext);
     }
 
     @Override

apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/SW8ExtensionCarrierItem.java

@@ -0,0 +1,35 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ *
+ */
+
+package org.apache.skywalking.apm.agent.core.context;
+
+public class SW8ExtensionCarrierItem extends CarrierItem {
+    public static final String HEADER_NAME = "sw8-x";
+    private final ExtensionContext extensionContext;
+
+    public SW8ExtensionCarrierItem(ExtensionContext extensionContext, CarrierItem next) {
+        super(HEADER_NAME, extensionContext.serialize(), next);
+        this.extensionContext = extensionContext;
+    }
+
+    @Override
+    public void setHeadValue(String headValue) {
+        this.extensionContext.deserialize(headValue);
+    }
+
+}

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

@@ -111,6 +111,7 @@ public class TracingContext implements AbstractTracerContext {
     private final ProfileStatusReference profileStatus;
 
     private final CorrelationContext correlationContext;
+    private final ExtensionContext extensionContext;
 
     /**
      * Initialize all fields with default value.
@@ -134,6 +135,7 @@ public class TracingContext implements AbstractTracerContext {
             this, segment.getTraceSegmentId(), firstOPName);
 
         this.correlationContext = new CorrelationContext();
+        this.extensionContext = new ExtensionContext();
     }
 
     /**
@@ -177,6 +179,7 @@ public void inject(AbstractSpan exitSpan, ContextCarrier carrier) {
         carrier.setAddressUsedAtClient(peer);
 
         this.correlationContext.inject(carrier);
+        this.extensionContext.inject(carrier);
     }
 
     /**
@@ -195,6 +198,8 @@ public void extract(ContextCarrier carrier) {
         }
 
         this.correlationContext.extract(carrier);
+        this.extensionContext.extract(carrier);
+        this.extensionContext.handle(span);
     }
 
     /**
@@ -209,7 +214,8 @@ public ContextSnapshot capture() {
             activeSpan().getSpanId(),
             getPrimaryTraceId(),
             first().getOperationName(),
-            this.correlationContext
+            this.correlationContext,
+            this.extensionContext
         );
 
         return snapshot;
@@ -228,6 +234,8 @@ public void continued(ContextSnapshot snapshot) {
             this.activeSpan().ref(segmentRef);
             this.segment.relatedGlobalTraces(snapshot.getTraceId());
             this.correlationContext.continued(snapshot);
+            this.extensionContext.continued(snapshot);
+            this.extensionContext.handle(this.activeSpan());
         }
     }
 
@@ -529,6 +537,7 @@ private AbstractSpan push(AbstractSpan span) {
             firstSpan = span;
         }
         activeSpanStack.addLast(span);
+        this.extensionContext.handle(span);
         return span;
     }
 

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

@@ -119,4 +119,9 @@ public interface AbstractSpan extends AsyncSpan {
      * @return true if the span's owner(tracing context main thread) is been profiled.
      */
     boolean isProfiling();
+
+    /**
+     * Should skip analysis in the backend.
+     */
+    void skipAnalysis();
 }

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

@@ -85,6 +85,11 @@ public abstract class AbstractTracingSpan implements AbstractSpan {
      */
     protected List<TraceSegmentRef> refs;
 
+    /**
+     * Tracing Mode. If true means represents all spans generated in this context should skip analysis.
+     */
+    protected boolean skipAnalysis;
+
     protected AbstractTracingSpan(int spanId, int parentSpanId, String operationName, TracingContext owner) {
         this.operationName = operationName;
         this.spanId = spanId;
@@ -246,6 +251,7 @@ public SpanObject.Builder transform() {
         spanBuilder.setStartTime(startTime);
         spanBuilder.setEndTime(endTime);
         spanBuilder.setOperationName(operationName);
+        spanBuilder.setSkipAnalysis(skipAnalysis);
         if (isEntry()) {
             spanBuilder.setSpanType(SpanType.Entry);
         } else if (isExit()) {
@@ -317,4 +323,9 @@ public AbstractSpan asyncFinish() {
     public boolean isProfiling() {
         return this.owner.profileStatus().isProfiling();
     }
+
+    @Override
+    public void skipAnalysis() {
+        this.skipAnalysis = true;
+    }
 }

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

@@ -119,6 +119,10 @@ public boolean isProfiling() {
         return false;
     }
 
+    @Override
+    public void skipAnalysis() {
+    }
+
     @Override
     public AbstractSpan prepareForAsync() {
         return this;

apm-sniffer/apm-agent-core/src/test/java/org/apache/skywalking/apm/agent/core/context/ContextCarrierV3HeaderTest.java

@@ -37,6 +37,8 @@ public void testDeserializeV3Header() {
                 next.setHeadValue("1-My40LjU=-MS4yLjM=-4-c2VydmljZQ==-aW5zdGFuY2U=-L2FwcA==-MTI3LjAuMC4xOjgwODA=");
             } else if (next.getHeadKey().equals(SW8CorrelationCarrierItem.HEADER_NAME)) {
                 next.setHeadValue("dGVzdA==:dHJ1ZQ==");
+            } else if (next.getHeadKey().equals(SW8ExtensionCarrierItem.HEADER_NAME)) {
+                next.setHeadValue("1");
             } else {
                 throw new IllegalArgumentException("Unknown Header: " + next.getHeadKey());
             }
@@ -61,6 +63,8 @@ public void testSerializeV3Header() {
 
         contextCarrier.getCorrelationContext().put("test", "true");
 
+        contextCarrier.getExtensionContext().deserialize("1");
+
         CarrierItem next = contextCarrier.items();
         while (next.hasNext()) {
             next = next.next();
@@ -73,6 +77,8 @@ public void testSerializeV3Header() {
                  * "test:true"
                  */
                 Assert.assertEquals("dGVzdA==:dHJ1ZQ==", next.getHeadValue());
+            } else if (next.getHeadKey().equals(SW8ExtensionCarrierItem.HEADER_NAME)) {
+                Assert.assertEquals("1", next.getHeadValue());
             } else {
                 throw new IllegalArgumentException("Unknown Header: " + next.getHeadKey());
             }
@@ -85,6 +91,8 @@ public void testSerializeV3Header() {
                 Assert.assertEquals("1-My40LjU=-MS4yLjM=-4-c2VydmljZQ==-aW5zdGFuY2U=-L2FwcA==-MTI3LjAuMC4xOjgwODA=", next.getHeadValue());
             } else if (next.getHeadKey().equals(SW8CorrelationCarrierItem.HEADER_NAME)) {
                 Assert.assertEquals("dGVzdA==:dHJ1ZQ==", next.getHeadValue());
+            } else if (next.getHeadKey().equals(SW8ExtensionCarrierItem.HEADER_NAME)) {
+                Assert.assertEquals("1", next.getHeadValue());
             } else {
                 throw new IllegalArgumentException("Unknown Header: " + next.getHeadKey());
             }
@@ -109,16 +117,20 @@ public void testV2HeaderAccurate() {
         contextCarrier.setParentEndpoint("/app");
 
         contextCarrier.getCorrelationContext().put("test", "true");
+        contextCarrier.getExtensionContext().deserialize("1");
 
         CarrierItem next = contextCarrier.items();
         String sw6HeaderValue = null;
         String correlationHeaderValue = null;
+        String extensionHeaderValue = null;
         while (next.hasNext()) {
             next = next.next();
             if (next.getHeadKey().equals(SW8CarrierItem.HEADER_NAME)) {
                 sw6HeaderValue = next.getHeadValue();
             } else if (next.getHeadKey().equals(SW8CorrelationCarrierItem.HEADER_NAME)) {
                 correlationHeaderValue = next.getHeadValue();
+            } else if (next.getHeadKey().equals(SW8ExtensionCarrierItem.HEADER_NAME)) {
+                extensionHeaderValue = next.getHeadValue();
             } else {
                 throw new IllegalArgumentException("Unknown Header: " + next.getHeadKey());
             }
@@ -132,6 +144,8 @@ public void testV2HeaderAccurate() {
                 next.setHeadValue(sw6HeaderValue);
             } else if (next.getHeadKey().equals(SW8CorrelationCarrierItem.HEADER_NAME)) {
                 next.setHeadValue(correlationHeaderValue);
+            } else if (next.getHeadKey().equals(SW8ExtensionCarrierItem.HEADER_NAME)) {
+                next.setHeadValue(extensionHeaderValue);
             } else {
                 throw new IllegalArgumentException("Unknown Header: " + next.getHeadKey());
             }
@@ -146,5 +160,6 @@ public void testV2HeaderAccurate() {
         Assert.assertEquals(contextCarrier.getParentServiceInstance(), contextCarrier2.getParentServiceInstance());
         Assert.assertEquals(contextCarrier.getParentEndpoint(), contextCarrier2.getParentEndpoint());
         Assert.assertEquals(contextCarrier.getCorrelationContext(), contextCarrier2.getCorrelationContext());
+        Assert.assertEquals(contextCarrier.getExtensionContext(), contextCarrier2.getExtensionContext());
     }
 }