etcdctlv3: support watch

A draft impl for demo.

etcdctlv3/command/watch_command.go

@@ -0,0 +1,101 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package command
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/codegangsta/cli"
+	"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
+	"github.com/coreos/etcd/Godeps/_workspace/src/google.golang.org/grpc"
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+)
+
+// NewWatchCommand returns the CLI command for "watch".
+func NewWatchCommand() cli.Command {
+	return cli.Command{
+		Name: "watch",
+		Action: func(c *cli.Context) {
+			watchCommandFunc(c)
+		},
+	}
+}
+
+// watchCommandFunc executes the "watch" command.
+func watchCommandFunc(c *cli.Context) {
+	conn, err := grpc.Dial(c.GlobalString("endpoint"))
+	if err != nil {
+		panic(err)
+	}
+
+	wAPI := pb.NewWatchClient(conn)
+	wStream, err := wAPI.Watch(context.TODO())
+	if err != nil {
+		panic(err)
+	}
+
+	go recvLoop(wStream)
+
+	reader := bufio.NewReader(os.Stdin)
+
+	for {
+		l, err := reader.ReadString('\n')
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error reading watch request line: %v", err)
+			os.Exit(1)
+		}
+		l = strings.TrimSuffix(l, "\n")
+
+		// TODO: support start and end revision
+		segs := strings.Split(l, " ")
+		if len(segs) != 2 {
+			fmt.Fprintf(os.Stderr, "Invaild watch request format: use watch key or watchprefix prefix\n")
+			continue
+		}
+
+		var r *pb.WatchRequest
+		switch segs[0] {
+		case "watch":
+			r = &pb.WatchRequest{Key: []byte(segs[1])}
+		case "watchprefix":
+			r = &pb.WatchRequest{Prefix: []byte(segs[1])}
+		default:
+			fmt.Fprintf(os.Stderr, "Invaild watch request format: use watch key or watchprefix prefix\n")
+			continue
+		}
+
+		err = wStream.Send(r)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error sending request to server: %v\n", err)
+		}
+	}
+}
+
+func recvLoop(wStream pb.Watch_WatchClient) {
+	for {
+		resp, err := wStream.Recv()
+		if err == io.EOF {
+			os.Exit(0)
+		}
+		if err != nil {
+			panic(err)
+		}
+		fmt.Printf("%s: %s %s\n", resp.Event.Type, string(resp.Event.Kv.Key), string(resp.Event.Kv.Value))
+	}
+}

etcdctlv3/main.go

@@ -36,6 +36,7 @@ func main() {
 		command.NewDeleteRangeCommand(),
 		command.NewTxnCommand(),
 		command.NewCompactionCommand(),
+		command.NewWatchCommand(),
 	}
 
 	app.Run(os.Args)