[Bug] Add exists check for IOCs index. (#1392) (#1395)

* Added check to prevent resource_already_exists_exception when indexing more than 10k iocs.



* Changed log message.



---------


(cherry picked from commit 4432b36)

Signed-off-by: AWSHurneyt <[email protected]>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

src/main/java/org/opensearch/securityanalytics/services/STIX2IOCFeedStore.java

@@ -9,6 +9,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.opensearch.OpenSearchException;
+import org.opensearch.ResourceAlreadyExistsException;
 import org.opensearch.action.DocWriteRequest;
 import org.opensearch.action.StepListener;
 import org.opensearch.action.admin.indices.create.CreateIndexRequest;
@@ -34,6 +35,7 @@
 import org.opensearch.securityanalytics.threatIntel.common.StashedThreadContext;
 import org.opensearch.securityanalytics.threatIntel.model.DefaultIocStoreConfig;
 import org.opensearch.securityanalytics.threatIntel.model.SATIFSourceConfig;
+import org.opensearch.transport.RemoteTransportException;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -241,6 +243,11 @@ private void initFeedIndex(String feedIndexName, ActionListener<CreateIndexRespo
                         listener.onResponse(r);
                     },
                     e -> {
+                        if (e instanceof ResourceAlreadyExistsException || (e instanceof RemoteTransportException && e.getCause() instanceof ResourceAlreadyExistsException)) {
+                            log.debug("index {} already exist", feedIndexName);
+                            listener.onResponse(null);
+                            return;
+                        }
                         log.error("Failed to create system index {}", feedIndexName);
                         listener.onFailure(e);
                     }