fix: Ensure to display version_conflict ES error message as warn - EX…

…O-74730

When we send analytics to ES, we firstly try to send it in a bulk.
If an element of the bulk generates an error in ES, we resend each request of the bulk one by one.
If the failed one is the i-st element, then request 1..i-1 will generated a version_conflict_engine_exception.
In 6.5, this was seen as a warn, an not generates an error.
In 7.0, it is seen as error, and then, like for each error, we try to resend it 5 times before dropping it, which could generate a log of logs.

This commit ensure to not raise an exception in this case :
- ES answer contains "error":true
AND ES answer contains "type":"version_conflict_engine_exception"
AND ES anwser concern only one entry.

If we have more than one entry, then we are in a bulk, and we cannot know which entry generated the version conflict, so we have to consider this as an error, and rerun each request separatly.

Resolves meesd-io/meeds#2487

analytics-services/src/main/java/io/meeds/analytics/elasticsearch/storage/ElasticsearchAnalyticsStorage.java

@@ -370,13 +370,24 @@ private boolean isError(int status) {
   }
 
   private ElasticsearchResponse handleESResponse(ElasticsearchResponse response, String uri, String content) {
-    if (isError(response) || StringUtils.contains(response.getMessage(), "\"errors\":true")) {
+    if (isError(response)) {
       throw new IllegalStateException(String.format("Error message returned from ES: %s. URI: %s. Content: %s",
                                                     response.getMessage(),
                                                     uri,
                                                     content));
-    } else if (StringUtils.contains(response.getMessage(), "\"type\":\"version_conflict_engine_exception\"")) {
-      LOG.warn("ID conflict in some content: {}", response.getMessage());
+    }
+    if (StringUtils.contains(response.getMessage(), "\"errors\":true")) {
+      if (StringUtils.contains(response.getMessage(), "\"type\":\"version_conflict_engine_exception\"")
+          && StringUtils.countMatches(response.getMessage(),"{\"create\":{") == 1) {
+        //the ES response is not answer of a bulk, but of a single insert
+        //it means the entry already exists in ES, no need to raise an error
+        LOG.warn("ID conflict in some content: {}", response.getMessage());
+      } else {
+        throw new IllegalStateException(String.format("Error message returned from ES: %s. URI: %s. Content: %s",
+                                                      response.getMessage(),
+                                                      uri,
+                                                      content));
+      }
     }
     return response;
   }