filer.meta.tail: support untilTimeAgo for a range

weed/command/filer_meta_tail.go

@@ -36,6 +36,7 @@ var (
 	tailFiler   = cmdFilerMetaTail.Flag.String("filer", "localhost:8888", "filer hostname:port")
 	tailTarget  = cmdFilerMetaTail.Flag.String("pathPrefix", "/", "path to a folder or common prefix for the folders or files on filer")
 	tailStart   = cmdFilerMetaTail.Flag.Duration("timeAgo", 0, "start time before now. \"300ms\", \"1.5h\" or \"2h45m\". Valid time units are \"ns\", \"us\" (or \"µs\"), \"ms\", \"s\", \"m\", \"h\"")
+	tailStop    = cmdFilerMetaTail.Flag.Duration("untilTimeAgo", 0, "read until this time ago. \"300ms\", \"1.5h\" or \"2h45m\". Valid time units are \"ns\", \"us\" (or \"µs\"), \"ms\", \"s\", \"m\", \"h\"")
 	tailPattern = cmdFilerMetaTail.Flag.String("pattern", "", "full path or just filename pattern, ex: \"/home/?opher\", \"*.pdf\", see https://golang.org/pkg/path/filepath/#Match ")
 	esServers   = cmdFilerMetaTail.Flag.String("es", "", "comma-separated elastic servers http://<host:port>")
 	esIndex     = cmdFilerMetaTail.Flag.String("es.index", "seaweedfs", "ES index name")
@@ -103,8 +104,13 @@ func runFilerMetaTail(cmd *Command, args []string) bool {
 		}
 	}
 
+	var untilTsNs int64
+	if *tailStop != 0 {
+		untilTsNs = time.Now().Add(-*tailStop).UnixNano()
+	}
+
 	tailErr := pb.FollowMetadata(pb.ServerAddress(*tailFiler), grpcDialOption, "tail", clientId, *tailTarget, nil,
-		time.Now().Add(-*tailStart).UnixNano(), 0, 0, func(resp *filer_pb.SubscribeMetadataResponse) error {
+		time.Now().Add(-*tailStart).UnixNano(), untilTsNs, 0, func(resp *filer_pb.SubscribeMetadataResponse) error {
 			if !shouldPrint(resp) {
 				return nil
 			}

weed/util/log_buffer/log_read.go

@@ -40,6 +40,10 @@ func (logBuffer *LogBuffer) LoopProcessLogData(readerName string, startReadTime
 		}
 		// glog.V(4).Infof("%s ReadFromBuffer by %v", readerName, lastReadTime)
 		if bytesBuf == nil {
+			if stopTsNs != 0 {
+				isDone = true
+				return
+			}
 			if waitForDataFn() {
 				continue
 			} else {