change from 'weed tail' to 'weed watch'

weed/command/watch.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() {
+	cmdWatch.Run = runWatch // break init cycle
+}
+
+var cmdWatch = &Command{
+	UsageLine: "watch <wip> [-filer=localhost:8888] [-target=/]",
+	Short:     "see recent changes on a filer",
+	Long: `See recent changes on a filer.
+
+  `,
+}
+
+var (
+	watchFiler  = cmdWatch.Flag.String("filer", "localhost:8888", "filer hostname:port")
+	watchTarget = cmdWatch.Flag.String("target", "/", "a folder or file on filer")
+)
+
+func runWatch(cmd *Command, args []string) bool {
+
+	grpcDialOption := security.LoadClientTLS(util.GetViper(), "grpc.client")
+
+	watchErr := pb.WithFilerClient(*watchFiler, grpcDialOption, func(client filer_pb.SeaweedFilerClient) error {
+
+		stream, err := client.ListenForEvents(context.Background(), &filer_pb.ListenForEventsRequest{
+			ClientName: "watch",
+			Directory:  *watchTarget,
+			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 watchErr != nil {
+		fmt.Printf("watch %s: %v\n", *watchFiler, watchErr)
+	}
+
+	return true
+}