avoid creating the same bucket with a different randomized name

related to https://github.com/chrislusf/seaweedfs/issues/2492

weed/command/filer_remote_gateway_buckets.go

@@ -86,6 +86,10 @@ func (option *RemoteGatewayOptions) makeBucketedEventProcessor(filerSource *sour
 				return nil
 			}
 		}
+
+		bucketPath := util.FullPath(option.bucketsDir).Child(entry.Name)
+		remoteLocation, found := option.mappings.Mappings[string(bucketPath)]
+		if !found {
 			if *option.createBucketRandomSuffix {
 				// https://docs.aws.amazon.com/AmazonS3/latest/userguide/bucketnamingrules.html
 				if len(bucketName)+5 > 63 {
@@ -93,21 +97,21 @@ func (option *RemoteGatewayOptions) makeBucketedEventProcessor(filerSource *sour
 				}
 				bucketName = fmt.Sprintf("%s-%04d", bucketName, rand.Uint32()%10000)
 			}
-
-		glog.V(0).Infof("create bucket %s", bucketName)
-		if err := client.CreateBucket(bucketName); err != nil {
-			return fmt.Errorf("create bucket %s in %s: %v", bucketName, remoteConf.Name, err)
-		}
-
-		bucketPath := util.FullPath(option.bucketsDir).Child(entry.Name)
-		remoteLocation := &remote_pb.RemoteStorageLocation{
+			remoteLocation = &remote_pb.RemoteStorageLocation{
 				Name:   *option.createBucketAt,
 				Bucket: bucketName,
 				Path:   "/",
 			}
-
-		// need to add new mapping here before getting upates from metadata tailing
+			// need to add new mapping here before getting updates from metadata tailing
 			option.mappings.Mappings[string(bucketPath)] = remoteLocation
+		} else {
+			bucketName = remoteLocation.Bucket
+		}
+
+		glog.V(0).Infof("create bucket %s", bucketName)
+		if err := client.CreateBucket(bucketName); err != nil {
+			return fmt.Errorf("create bucket %s in %s: %v", bucketName, remoteConf.Name, err)
+		}
 
 		return filer.InsertMountMapping(option, string(bucketPath), remoteLocation)