[BUG] ArrayIndexOutOfBoundsException for inconsistent detector index behavior (#843) (#906)

* Catch ArrayIndexOutOfBoundsException when detector is missing

Signed-off-by: Megha Goyal <[email protected]>

* Add a check on SearchHits.getHits() length

Signed-off-by: Megha Goyal <[email protected]>

* Remove index out of bounds exception

Signed-off-by: Megha Goyal <[email protected]>

---------

Signed-off-by: Megha Goyal <[email protected]>
(cherry picked from commit 0ef8543)

Co-authored-by: Megha Goyal <[email protected]>

Author: opensearch-trigger-bot[bot]

src/main/java/org/opensearch/securityanalytics/transport/TransportCorrelateFindingAction.java

@@ -221,7 +221,8 @@ public void onResponse(SearchResponse response) {
                         }
 
                         SearchHits hits = response.getHits();
-                        if (hits.getTotalHits().value == 1) {
+                        // Detectors Index hits count could be more even if we fetch one
+                        if (hits.getTotalHits().value >= 1 && hits.getHits().length > 0) {
                             try {
                                 SearchHit hit = hits.getAt(0);
 
@@ -232,6 +233,7 @@ public void onResponse(SearchResponse response) {
                                 Detector detector = Detector.docParse(xcp, hit.getId(), hit.getVersion());
                                 joinEngine.onSearchDetectorResponse(detector, finding);
                             } catch (IOException e) {
+                                log.error("IOException for request {}", searchRequest.toString(), e);
                                 onFailures(e);
                             }
                         } else {