filer: able to tail meta data changes

2 files changed, 71 insertions, 7 deletions

diff --git a/weed/command/command.go b/weed/command/command.go
index 9dc51e922..a82f3cdd0 100644
--- a/weed/command/command.go
+++ b/weed/command/command.go
@@ -12,21 +12,22 @@ var Commands = []*Command{
 	cmdBackup,
 	cmdCompact,
 	cmdCopy,
-	cmdFix,
+	cmdDownload,
+	cmdExport,
+	cmdFiler,
 	cmdFilerReplicate,
-	cmdServer,
+	cmdFix,
 	cmdMaster,
-	cmdFiler,
+	cmdMount,
 	cmdS3,
-	cmdUpload,
-	cmdDownload,
 	cmdMsgBroker,
 	cmdScaffold,
+	cmdServer,
 	cmdShell,
+	cmdTail,
+	cmdUpload,
 	cmdVersion,
 	cmdVolume,
-	cmdExport,
-	cmdMount,
 	cmdWebDav,
 }
 
diff --git a/weed/command/tail.go b/weed/command/tail.go
new file mode 100644
index 000000000..e81a4cfe2
--- /dev/null
+++ b/weed/command/tail.go
@@ -0,0 +1,63 @@
+package command
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"github.com/chrislusf/seaweedfs/weed/pb"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/security"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+func init() {
+	cmdTail.Run = runTail // break init cycle
+}
+
+var cmdTail = &Command{
+	UsageLine: "tail <wip> [-filer=localhost:8888]",
+	Short:     "see recent changes on a filer",
+	Long: `See recent changes on a filer.
+
+  `,
+}
+
+var (
+	tailFiler  = cmdTail.Flag.String("filer", "localhost:8888", "filer hostname:port")
+	tailTarget = cmdTail.Flag.String("target", "/", "a folder or file on filer")
+)
+
+func runTail(cmd *Command, args []string) bool {
+
+	grpcDialOption := security.LoadClientTLS(util.GetViper(), "grpc.client")
+
+	tailErr := pb.WithFilerClient(*tailFiler, grpcDialOption, func(client filer_pb.SeaweedFilerClient) error {
+
+		stream, err := client.ListenForEvents(context.Background(), &filer_pb.ListenForEventsRequest{
+			ClientName: "tail",
+			Directory:  *tailTarget,
+			SinceNs:    0,
+		})
+		if err != nil {
+			return fmt.Errorf("listen: %v", err)
+		}
+
+		for {
+			resp, listenErr := stream.Recv()
+			if listenErr == io.EOF {
+				return nil
+			}
+			if listenErr != nil {
+				return listenErr
+			}
+			fmt.Printf("events: %+v\n", resp.EventNotification)
+		}
+
+	})
+	if tailErr != nil {
+		fmt.Printf("tail %s: %v\n", *tailFiler, tailErr)
+	}
+
+	return true
+}