Propagate trace info when sending messages to ActiveMQ with null properties
#### Description
ActiveMQ plugin injects pinpoint-specific headers into ActiveMQ's **AMQP.BasicProperties** to propagate trace info over to the consumer.
However, it is valid to have the sender supply `null` for **AMQP.BasicProperties** in which case, ActiveMQ plugin cannot propagate trace info over to the consumer as it does not have any object in which to inject the headers.
We might have to delay the header injection in order to support these scenarios.
related issue - #4463 
plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientConstants.java plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientPlugin.java plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/ChannelBasicPublishInterceptor.java
plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientConstants.java plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientPlugin.java plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/aspect/ChannelAspect.java plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/AMQCommandConstructInterceptor.java plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/ChannelBasicPublishInterceptor.java
diff --git a/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientConstants.java b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientConstants.java
index 70487fd9f64f..e3046c0b4f6d 100644
--- a/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientConstants.java
+++ b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientConstants.java
@@ -36,7 +36,7 @@ private RabbitMQClientConstants() {
     public static final ServiceType RABBITMQ_CLIENT = ServiceTypeFactory.of(8300, "RABBITMQ_CLIENT", QUEUE, RECORD_STATISTICS);
     public static final ServiceType RABBITMQ_CLIENT_INTERNAL = ServiceTypeFactory.of(8301, "RABBITMQ_CLIENT_INTERNAL", "RABBITMQ_CLIENT");
 
-    public static final String RABBITMQ_SCOPE = "rabbitmqScope";
+    public static final String RABBITMQ_PRODUCER_SCOPE = "rabbitmqProducerScope";
     public static final String RABBITMQ_CONSUMER_SCOPE = "rabbitmqConsumerScope";
     public static final String RABBITMQ_FRAME_HANDLER_CREATION_SCOPE = "rabbitmqFrameHandlerCreationScope";
     public static final String RABBITMQ_TEMPLATE_API_SCOPE = "rabbitmqTemplateApiScope";
diff --git a/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientPlugin.java b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientPlugin.java
index e31fdbf35cfc..fe0a042d21ef 100644
--- a/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientPlugin.java
+++ b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/RabbitMQClientPlugin.java
@@ -93,9 +93,12 @@ private ChannelTransformCallback(boolean traceProducer, boolean traceConsumer) {
         public byte[] doInTransform(Instrumentor instrumentor, ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws InstrumentException {
             InstrumentClass target = instrumentor.getInstrumentClass(loader, className, classfileBuffer);
             if (traceProducer) {
+                // copy AMQP.BasicProperties
+                target.weave("com.navercorp.pinpoint.plugin.rabbitmq.client.aspect.ChannelAspect");
+
                 final InstrumentMethod basicPublish = target.getDeclaredMethod("basicPublish", "java.lang.String", "java.lang.String", "boolean", "boolean", "com.rabbitmq.client.AMQP$BasicProperties", "byte[]");
                 if (basicPublish != null) {
-                    basicPublish.addScopedInterceptor("com.navercorp.pinpoint.plugin.rabbitmq.client.interceptor.ChannelBasicPublishInterceptor", RabbitMQClientConstants.RABBITMQ_SCOPE);
+                    basicPublish.addScopedInterceptor("com.navercorp.pinpoint.plugin.rabbitmq.client.interceptor.ChannelBasicPublishInterceptor", RabbitMQClientConstants.RABBITMQ_PRODUCER_SCOPE, ExecutionPolicy.BOUNDARY);
                 }
             }
             if (traceConsumer) {
@@ -155,6 +158,18 @@ public byte[] doInTransform(Instrumentor instrumentor, ClassLoader loader, Strin
                 return target.toBytecode();
             }
         });
+        // AMQCommand - for pinpoint header propagation
+        transformTemplate.transform("com.rabbitmq.client.impl.AMQCommand", new TransformCallback() {
+            @Override
+            public byte[] doInTransform(Instrumentor instrumentor, ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws InstrumentException {
+                InstrumentClass target = instrumentor.getInstrumentClass(loader, className, classfileBuffer);
+                InstrumentMethod constructor = target.getConstructor("com.rabbitmq.client.Method", "com.rabbitmq.client.impl.AMQContentHeader", "byte[]");
+                if (constructor != null) {
+                    constructor.addScopedInterceptor("com.navercorp.pinpoint.plugin.rabbitmq.client.interceptor.AMQCommandConstructInterceptor", RabbitMQClientConstants.RABBITMQ_PRODUCER_SCOPE, ExecutionPolicy.INTERNAL);
+                }
+                return target.toBytecode();
+            }
+        });
     }
 
     private void addAMQChannelEditor(final Filter<String> excludeExchangeFilter) {
diff --git a/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/aspect/ChannelAspect.java b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/aspect/ChannelAspect.java
new file mode 100644
index 000000000000..810ceb40bdbd
--- /dev/null
+++ b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/aspect/ChannelAspect.java
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2018 NAVER Corp.
+ *
+ * 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.
+ */
+
+package com.navercorp.pinpoint.plugin.rabbitmq.client.aspect;
+
+import com.navercorp.pinpoint.bootstrap.instrument.aspect.Aspect;
+import com.navercorp.pinpoint.bootstrap.instrument.aspect.JointPoint;
+import com.navercorp.pinpoint.bootstrap.instrument.aspect.PointCut;
+import com.rabbitmq.client.AMQP;
+import com.rabbitmq.client.MessageProperties;
+
+/**
+ * Make a copy of {@code AMQP.BasicProperties} to inject pinpoint headers.
+ *
+ * @author HyunGil Jeong
+ */
+@Aspect
+public abstract class ChannelAspect {
+    @PointCut
+    public void basicPublish(String exchange, String routingKey,
+                             boolean mandatory, boolean immediate,
+                             AMQP.BasicProperties props, byte[] body) {
+        AMQP.BasicProperties sourceProps = props;
+        if (sourceProps == null) {
+            sourceProps = MessageProperties.MINIMAL_BASIC;
+        }
+        AMQP.BasicProperties useProps = copy(sourceProps);
+        __basicPublish(exchange, routingKey, mandatory, immediate, useProps, body);
+    }
+
+    private AMQP.BasicProperties copy(AMQP.BasicProperties source) {
+        AMQP.BasicProperties.Builder builder = new AMQP.BasicProperties.Builder();
+        builder.contentType(source.getContentType());
+        builder.contentEncoding(source.getContentEncoding());
+        builder.headers(source.getHeaders());
+        builder.deliveryMode(source.getDeliveryMode());
+        builder.priority(source.getPriority());
+        builder.correlationId(source.getCorrelationId());
+        builder.replyTo(source.getReplyTo());
+        builder.expiration(source.getExpiration());
+        builder.messageId(source.getMessageId());
+        builder.timestamp(source.getTimestamp());
+        builder.type(source.getType());
+        builder.userId(source.getUserId());
+        builder.appId(source.getAppId());
+        builder.clusterId(source.getClusterId());
+        return builder.build();
+    }
+
+    @JointPoint
+    abstract void __basicPublish(String exchange, String routingKey,
+                                 boolean mandatory, boolean immediate,
+                                 AMQP.BasicProperties props, byte[] body);
+}
diff --git a/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/AMQCommandConstructInterceptor.java b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/AMQCommandConstructInterceptor.java
new file mode 100644
index 000000000000..948e6333cd50
--- /dev/null
+++ b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/AMQCommandConstructInterceptor.java
@@ -0,0 +1,181 @@
+/*
+ * Copyright 2018 NAVER Corp.
+ *
+ * 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.
+ */
+
+package com.navercorp.pinpoint.plugin.rabbitmq.client.interceptor;
+
+import com.navercorp.pinpoint.bootstrap.context.Trace;
+import com.navercorp.pinpoint.bootstrap.context.TraceContext;
+import com.navercorp.pinpoint.bootstrap.context.TraceId;
+import com.navercorp.pinpoint.bootstrap.interceptor.AroundInterceptor;
+import com.navercorp.pinpoint.bootstrap.interceptor.scope.InterceptorScope;
+import com.navercorp.pinpoint.bootstrap.logging.PLogger;
+import com.navercorp.pinpoint.bootstrap.logging.PLoggerFactory;
+import com.navercorp.pinpoint.common.util.MapUtils;
+import com.navercorp.pinpoint.plugin.rabbitmq.client.RabbitMQClientConstants;
+import com.navercorp.pinpoint.plugin.rabbitmq.client.field.setter.HeadersFieldSetter;
+import com.rabbitmq.client.AMQP;
+import com.rabbitmq.client.Method;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * <p>{@code AMQContentHeader} received as an argument to the constructor is sharable and can be reused, such as
+ * {@code MessageProperties.MINIMAL_BASIC}. Any changes made to it (ie injecting pinpoint headers) may have undesirable
+ * consequences.
+ *
+ * <p>Hence, we make a copy via {@code ChannelAspect} and add pinpoint headers to it when propagating trace, and have
+ * {@code AMQCommand} use this.
+ *
+ * @author HyunGil Jeong
+ *
+ * @see com.navercorp.pinpoint.plugin.rabbitmq.client.aspect.ChannelAspect
+ */
+public class AMQCommandConstructInterceptor implements AroundInterceptor {
+
+    // AMQP spec
+    private static final String AMQP_METHOD_TO_INTERCEPT = "basic.publish";
+
+    private final PLogger logger = PLoggerFactory.getLogger(this.getClass());
+    private final boolean isDebug = logger.isDebugEnabled();
+
+    private final TraceContext traceContext;
+    private final InterceptorScope scope;
+
+    public AMQCommandConstructInterceptor(TraceContext traceContext, InterceptorScope scope) {
+        this.traceContext = traceContext;
+        this.scope = scope;
+    }
+
+    @Override
+    public void before(Object target, Object[] args) {
+        if (!validate(target, args)) {
+            return;
+        }
+
+        if (isDebug) {
+            logger.beforeInterceptor(target, args);
+        }
+
+        Trace trace = traceContext.currentRawTraceObject();
+        if (trace == null) {
+            return;
+        }
+
+        final AMQP.BasicProperties properties = (AMQP.BasicProperties) args[1];
+        final Map<String, Object> headers = createHeader(properties, trace);
+        if (headers != null) {
+            ((HeadersFieldSetter) properties)._$PINPOINT$_setHeaders(headers);
+        }
+    }
+
+    private Map<String, Object> createHeader(AMQP.BasicProperties properties, Trace trace) {
+        final Map<String, Object> headers = copyHeader(properties);
+        if (trace.canSampled()) {
+            TraceId nextId = retrieveNextTraceId();
+            if (nextId == null) {
+                return null;
+            }
+            headers.put(RabbitMQClientConstants.META_TRACE_ID, nextId.getTransactionId());
+            headers.put(RabbitMQClientConstants.META_SPAN_ID, Long.toString(nextId.getSpanId()));
+            headers.put(RabbitMQClientConstants.META_PARENT_SPAN_ID, Long.toString(nextId.getParentSpanId()));
+            headers.put(RabbitMQClientConstants.META_PARENT_APPLICATION_TYPE, Short.toString(traceContext.getServerTypeCode()));
+            headers.put(RabbitMQClientConstants.META_PARENT_APPLICATION_NAME, traceContext.getApplicationName());
+            headers.put(RabbitMQClientConstants.META_FLAGS, Short.toString(nextId.getFlags()));
+        } else {
+            headers.put(RabbitMQClientConstants.META_SAMPLED, "1");
+        }
+        return headers;
+    }
+
+    private Map<String, Object> copyHeader(AMQP.BasicProperties properties) {
+        final Map<String, Object> headers = properties.getHeaders();
+        if (MapUtils.isEmpty(headers)) {
+            return new HashMap<String, Object>();
+        }
+        // headers wrapped as unmodifiable map
+        return new HashMap<String, Object>(headers);
+    }
+
+    private TraceId retrieveNextTraceId() {
+        Object attachment = scope.getCurrentInvocation().getAttachment();
+        if (attachment == null) {
+            if (isDebug) {
+                logger.debug("Invalid attachment. Expected {}, but got null", TraceId.class.getName());
+            }
+            return null;
+        }
+        if (!(attachment instanceof TraceId)) {
+            if (isDebug) {
+                logger.debug("Invalid attachment. Expected {}, but got {}", TraceId.class.getName(), attachment.getClass());
+            }
+            return null;
+        }
+        return (TraceId) attachment;
+    }
+
+    @Override
+    public void after(Object target, Object[] args, Object result, Throwable throwable) {
+        if (!validate(target, args)) {
+            return;
+        }
+
+        if (isDebug) {
+            logger.afterInterceptor(target, args);
+        }
+    }
+
+    private boolean validate(Object target, Object[] args) {
+        if (args == null) {
+            if (isDebug) {
+                logger.debug("Expected arguments, but found none.");
+            }
+            return false;
+        }
+        if (args.length != 3) {
+            if (isDebug) {
+                logger.debug("Expected 3 arguments, but found {}", args.length);
+            }
+            return false;
+        }
+        Object method = args[0];
+        if (method == null) {
+            // valid, but this won't be null producer side
+            return false;
+        }
+        if (!(method instanceof Method)) {
+            if (isDebug) {
+                logger.debug("Expected args[0] to be {}, but was {}", Method.class.getName(), method.getClass().getName());
+            }
+            return false;
+        }
+        if (!AMQP_METHOD_TO_INTERCEPT.equals(((Method) method).protocolMethodName())) {
+            return false;
+        }
+        Object contentHeader = args[1];
+        if (!(contentHeader instanceof AMQP.BasicProperties)) {
+            // skip header injection for null, or non AMQP.BasicProperties header
+            return false;
+        }
+        if (!(contentHeader instanceof HeadersFieldSetter)) {
+            if (isDebug) {
+                logger.debug("Invalid args[1]({}) object. Need field setter({})", contentHeader, HeadersFieldSetter.class.getName());
+            }
+            return false;
+        }
+        return true;
+    }
+}
diff --git a/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/ChannelBasicPublishInterceptor.java b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/ChannelBasicPublishInterceptor.java
index aaf059a852c9..c3e0050d3469 100644
--- a/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/ChannelBasicPublishInterceptor.java
+++ b/plugins/rabbitmq/src/main/java/com/navercorp/pinpoint/plugin/rabbitmq/client/interceptor/ChannelBasicPublishInterceptor.java
@@ -7,25 +7,23 @@
 import com.navercorp.pinpoint.bootstrap.context.TraceContext;
 import com.navercorp.pinpoint.bootstrap.context.TraceId;
 import com.navercorp.pinpoint.bootstrap.interceptor.AroundInterceptor;
+import com.navercorp.pinpoint.bootstrap.interceptor.scope.InterceptorScope;
+import com.navercorp.pinpoint.bootstrap.interceptor.scope.InterceptorScopeInvocation;
 import com.navercorp.pinpoint.bootstrap.logging.PLogger;
 import com.navercorp.pinpoint.bootstrap.logging.PLoggerFactory;
-import com.navercorp.pinpoint.common.util.MapUtils;
 import com.navercorp.pinpoint.plugin.rabbitmq.client.RabbitMQClientPluginConfig;
 import com.navercorp.pinpoint.plugin.rabbitmq.client.RabbitMQClientConstants;
 import com.navercorp.pinpoint.plugin.rabbitmq.client.field.accessor.RemoteAddressAccessor;
-import com.navercorp.pinpoint.plugin.rabbitmq.client.field.setter.HeadersFieldSetter;
 import com.rabbitmq.client.AMQP;
 import com.rabbitmq.client.Channel;
 import com.rabbitmq.client.Connection;
 import com.rabbitmq.client.impl.AMQConnection;
 import com.rabbitmq.client.impl.FrameHandler;
 
-import java.util.HashMap;
-import java.util.Map;
-
 /**
  * @author Jinkai.Ma
  * @author Jiaqi Feng
+ * @author HyunGil Jeong
  */
 public class ChannelBasicPublishInterceptor implements AroundInterceptor {
 
@@ -34,11 +32,13 @@ public class ChannelBasicPublishInterceptor implements AroundInterceptor {
 
     private final MethodDescriptor descriptor;
     private final TraceContext traceContext;
+    private final InterceptorScope scope;
     private final Filter<String> excludeExchangeFilter;
 
-    public ChannelBasicPublishInterceptor(TraceContext traceContext, MethodDescriptor descriptor) {
+    public ChannelBasicPublishInterceptor(TraceContext traceContext, MethodDescriptor descriptor, InterceptorScope scope) {
         this.descriptor = descriptor;
         this.traceContext = traceContext;
+        this.scope = scope;
 
         RabbitMQClientPluginConfig rabbitMQClientPluginConfig = new RabbitMQClientPluginConfig(traceContext.getProfilerConfig());
         this.excludeExchangeFilter = rabbitMQClientPluginConfig.getExcludeExchangeFilter();
@@ -65,8 +65,6 @@ public void before(Object target, Object[] args) {
         if (trace == null) {
             return;
         }
-        final AMQP.BasicProperties properties = (AMQP.BasicProperties) args[4];
-        final Map<String, Object> headers = copyHeader(properties);
 
         if (trace.canSampled()) {
             SpanEventRecorder recorder = trace.traceBlockBegin();
@@ -76,34 +74,11 @@ public void before(Object target, Object[] args) {
 
             recorder.recordNextSpanId(nextId.getSpanId());
 
-            headers.put(RabbitMQClientConstants.META_TRACE_ID, nextId.getTransactionId());
-            headers.put(RabbitMQClientConstants.META_SPAN_ID, Long.toString(nextId.getSpanId()));
-            headers.put(RabbitMQClientConstants.META_PARENT_SPAN_ID, Long.toString(nextId.getParentSpanId()));
-            headers.put(RabbitMQClientConstants.META_PARENT_APPLICATION_TYPE, Short.toString(traceContext.getServerTypeCode()));
-            headers.put(RabbitMQClientConstants.META_PARENT_APPLICATION_NAME, traceContext.getApplicationName());
-            headers.put(RabbitMQClientConstants.META_FLAGS, Short.toString(nextId.getFlags()));
-        } else {
-            headers.put(RabbitMQClientConstants.META_SAMPLED, "1");
-        }
-
-        if (properties instanceof HeadersFieldSetter) {
-            ((HeadersFieldSetter) properties)._$PINPOINT$_setHeaders(headers);
+            InterceptorScopeInvocation invocation = scope.getCurrentInvocation();
+            invocation.setAttachment(nextId);
         }
     }
 
-    private Map<String, Object> copyHeader(AMQP.BasicProperties properties) {
-        if (properties == null) {
-            return new HashMap<String, Object>();
-        }
-
-        final Map<String, Object> headers = properties.getHeaders();
-        if (MapUtils.isEmpty(headers)) {
-            return new HashMap<String, Object>();
-        }
-
-        return new HashMap<String, Object>(headers);
-    }
-
     @Override
     public void after(Object target, Object[] args, Object result, Throwable throwable) {
         if (isDebug) {
