Including extended request id in event stream response

Author: shorea

core/aws-core/src/main/java/software/amazon/awssdk/awscore/eventstream/EventStreamAsyncResponseTransformer.java

@@ -16,6 +16,7 @@
 package software.amazon.awssdk.awscore.eventstream;
 
 import static software.amazon.awssdk.core.http.HttpResponseHandler.X_AMZN_REQUEST_ID_HEADER;
+import static software.amazon.awssdk.core.http.HttpResponseHandler.X_AMZ_ID_2_HEADER;
 import static software.amazon.awssdk.utils.FunctionalUtils.runAndLogError;
 
 import java.io.ByteArrayInputStream;
@@ -156,6 +157,13 @@ public class EventStreamAsyncResponseTransformer<ResponseT, EventT>
      */
     private String requestId = null;
 
+    /**
+     * Extended Request Id for the streaming request. The value is populated when the initial response is received from the
+     * service. As request id is not sent in event messages (including exceptions), this can be returned by the SDK along with
+     * received exception details.
+     */
+    private String extendedRequestId = null;
+
     @Deprecated
     @ReviewBeforeRelease("Remove this on full GA of 2.0.0")
     public EventStreamAsyncResponseTransformer(
@@ -194,6 +202,9 @@ public void responseReceived(SdkResponse response) {
             this.requestId = response.sdkHttpResponse()
                                      .firstMatchingHeader(X_AMZN_REQUEST_ID_HEADER)
                                      .orElse(null);
+            this.extendedRequestId = response.sdkHttpResponse()
+                                             .firstMatchingHeader(X_AMZ_ID_2_HEADER)
+                                             .orElse(null);
         }
     }
 
@@ -324,6 +335,9 @@ private HttpResponse adaptMessageToResponse(Message m, boolean isException) {
         if (requestId != null) {
             response.addHeader(X_AMZN_REQUEST_ID_HEADER, requestId);
         }
+        if (extendedRequestId != null) {
+            response.addHeader(X_AMZ_ID_2_HEADER, extendedRequestId);
+        }
 
         //TODO: fix the hard-coded status code
         response.setStatusCode(isException ? 500 : 200);

core/sdk-core/src/main/java/software/amazon/awssdk/core/http/HttpResponseHandler.java

@@ -33,6 +33,8 @@ public interface HttpResponseHandler<T> {
 
     String X_AMZN_REQUEST_ID_HEADER = "x-amzn-RequestId";
 
+    String X_AMZ_ID_2_HEADER = "x-amz-id-2";
+
     /**
      * Accepts an HTTP response object, and returns an object of type T.
      * Individual implementations may choose to handle the response however they