[sync] override amz storage class, None to delete (#3639)

* override amz storage class, None to delete
https://github.com/seaweedfs/seaweedfs/issues/3636

* use empty string to delete

* without nil check

weed/command/filer_remote_sync.go

@@ -14,6 +14,7 @@ import (
 
 type RemoteSyncOptions struct {
 	filerAddress       *string
+	storageClass       *string
 	grpcDialOption     grpc.DialOption
 	readChunkFromFiler *bool
 	timeAgo            *time.Duration
@@ -45,6 +46,7 @@ func init() {
 	cmdFilerRemoteSynchronize.Run = runFilerRemoteSynchronize // break init cycle
 	remoteSyncOptions.filerAddress = cmdFilerRemoteSynchronize.Flag.String("filer", "localhost:8888", "filer of the SeaweedFS cluster")
 	remoteSyncOptions.dir = cmdFilerRemoteSynchronize.Flag.String("dir", "", "a mounted directory on filer")
+	remoteSyncOptions.storageClass = cmdFilerRemoteSynchronize.Flag.String("storageClass", "None", "override amz storage class, empty to delete")
 	remoteSyncOptions.readChunkFromFiler = cmdFilerRemoteSynchronize.Flag.Bool("filerProxy", false, "read file chunks from filer instead of volume servers")
 	remoteSyncOptions.timeAgo = cmdFilerRemoteSynchronize.Flag.Duration("timeAgo", 0, "start time before now, skipping previous metadata changes. \"300ms\", \"1.5h\" or \"2h45m\". Valid time units are \"ns\", \"us\" (or \"µs\"), \"ms\", \"s\", \"m\", \"h\"")
 	remoteSyncOptions.clientId = util.RandomInt32()

weed/command/filer_remote_sync_dir.go

@@ -37,6 +37,12 @@ func followUpdatesAndUploadToRemote(option *RemoteSyncOptions, filerSource *sour
 
 	var lastLogTsNs = time.Now().UnixNano()
 	processEventFnWithOffset := pb.AddOffsetFunc(func(resp *filer_pb.SubscribeMetadataResponse) error {
+		storageClass := *option.storageClass
+		if storageClass == "" {
+			delete(resp.EventNotification.NewEntry.Extended, s3_constants.AmzStorageClass)
+		} else if storageClass != "None" {
+			resp.EventNotification.NewEntry.Extended[s3_constants.AmzStorageClass] = []byte(storageClass)
+		}
 		processor.AddSyncJob(resp)
 		return nil
 	}, 3*time.Second, func(counter int64, lastTsNs int64) error {

weed/command/filer_sync_jobs.go

@@ -54,7 +54,7 @@ func (t *MetadataProcessor) AddSyncJob(resp *filer_pb.SubscribeMetadataResponse)
 
 		// if is the oldest job, write down the watermark
 		isOldest := true
-		for t, _ := range t.activeJobs {
+		for t := range t.activeJobs {
 			if resp.TsNs > t {
 				isOldest = false
 				break