delete-marker set user md

lib/api/apiUtils/object/createAndStoreObject.js

@@ -19,6 +19,21 @@ const { externalBackends, versioningNotImplBackends } = constants;
 const externalVersioningErrorMessage = 'We do not currently support putting ' +
 'a versioned object to a location-constraint of type Azure.';
 
+// if receiving a request from Zenko, we place a user-metadata
+// field on the object, including delete markers
+function _placeZenkoStamp(request, metaHeaders, isDeleteMarker) {
+    const zenkoIdentifierHeader = 'x-amz-meta-zenko-source';
+    const userAgent = request.headers['user-agent'];
+
+    // if the request came from Zenko, add user-metadata on this delete marker
+    // for internal use
+    if (isDeleteMarker) {
+        if (userAgent && userAgent.includes('Zenko')) {
+            // eslint-disable-next-line no-param-reassign
+            metaHeaders[zenkoIdentifierHeader] = 'zenko';
+        }
+    }
+}
 
 function _storeInMDandDeleteData(bucketName, dataGetInfo, cipherBundle,
     metadataStoreParams, dataToDelete, deleteLog, requestMethod, callback) {