refactor: address review feedback for global OpenSearch index prefix

Author: mezzeddine

docs/source/AdministratorGuide/ExternalsSupport/index.rst

@@ -55,7 +55,7 @@ You can run your OpenSearch cluster without authentication, or using User name a
   - ``ca_certs`` (default:``None``)
   - ``client_key`` (default:``None``)
   - ``client_cert`` (default:``None``)
-  - ``IndexPrefix`` (default:``''``). Prefix prepended to all DIRAC-created OpenSearch indexes.
+  - ``IndexPrefix`` (default:``''``). Prefix prepended to all DIRAC-created OpenSearch indexes. The prefix will be lower case only.
 
 
 to the location::

src/DIRAC/Core/Utilities/ElasticSearchDB.py

@@ -127,7 +127,7 @@ def __init__(
         """
 
         self._connected = False
-        self._globalIndexPrefix = (globalIndexPrefix or "").strip().lower()
+        self.globalIndexPrefix = globalIndexPrefix
         if user and password:
             sLog.debug("Specified username and password")
             password = urlparse.quote_plus(password)
@@ -194,17 +194,20 @@ def __init__(
         except ElasticConnectionError as e:
             sLog.error(repr(e))
 
+    @property
+    def globalIndexPrefix(self) -> str:
+        """Global prefix prepended to all index names and patterns."""
+        return self._globalIndexPrefix
+
+    @globalIndexPrefix.setter
+    def globalIndexPrefix(self, value: str):
+        self._globalIndexPrefix = (value or "").strip().lower()
+
     def _withGlobalPrefix(self, indexName):
         """Prepend the global index prefix to an index name or pattern."""
         if not self._globalIndexPrefix:
             return indexName
 
-        if isinstance(indexName, (list, tuple)):
-            return [self._withGlobalPrefix(name) for name in indexName]
-
-        if not isinstance(indexName, str):
-            return indexName
-
         prefixedTokens = []
         for token in indexName.split(","):
             strippedToken = token.strip()
@@ -556,9 +559,9 @@ def bulk_index(self, indexPrefix, data=None, mapping=None, period="day", withTim
             indexName = self.generateFullIndexName(indexPrefix, period)
         else:
             indexName = indexPrefix
-        indexName = self._withGlobalPrefix(indexName)
-        sLog.debug(f"Bulk indexing into {indexName} of {len(data)}")
+        sLog.debug(f"Bulk indexing into {self._withGlobalPrefix(indexName)} of {len(data)}")
 
+        # Keep existence/creation checks on the raw name path; methods apply global prefix internally.
         res = self.existingIndex(indexName)
         if not res["OK"]:
             return res
@@ -567,6 +570,9 @@ def bulk_index(self, indexPrefix, data=None, mapping=None, period="day", withTim
             if not retVal["OK"]:
                 return retVal
 
+        # Prefix exactly once for the direct bulk API call.
+        indexName = self._withGlobalPrefix(indexName)
+
         try:
             res = bulk(client=self.client, index=indexName, actions=generateDocs(data, withTimeStamp))
         except (BulkIndexError, RequestError) as e: