hanlde the throttling error in the response header

Signed-off-by: Xun Zhang <[email protected]>

ml-algorithms/src/main/java/org/opensearch/ml/engine/algorithms/remote/MLSdkAsyncHttpResponseHandler.java

@@ -16,6 +16,7 @@
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.collections.MapUtils;
 import org.apache.http.HttpStatus;
 import org.apache.logging.log4j.util.Strings;
 import org.opensearch.OpenSearchStatusException;
@@ -80,6 +81,23 @@ public void onHeaders(SdkHttpResponse response) {
         SdkHttpFullResponse sdkResponse = (SdkHttpFullResponse) response;
         log.debug("received response headers: " + sdkResponse.headers());
         this.statusCode = sdkResponse.statusCode();
+        if (MapUtils.isEmpty(sdkResponse.headers())) {
+            return;
+        }
+        List<String> errorsInHeader = sdkResponse.headers().get("x-amzn-ErrorType");
+        if (errorsInHeader == null || errorsInHeader.isEmpty()) {
+            return;
+        }
+        boolean containsThrottlingException = errorsInHeader.stream().anyMatch(str -> str.startsWith("ThrottlingException"));
+        if (containsThrottlingException) {
+            actionListener
+                .onFailure(
+                    new OpenSearchStatusException(
+                        REMOTE_SERVICE_ERROR + "The request was denied due to request throttling.",
+                        RestStatus.fromCode(statusCode)
+                    )
+                );
+        }
     }
 
     @Override