etcdctl/ctlv3: add 'move-leader' command

Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>

e2e/ctl_v3_move_leader_test.go

@@ -0,0 +1,92 @@
+// Copyright 2017 The etcd Authors
+//
+// 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 e2e
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/coreos/etcd/clientv3"
+	"github.com/coreos/etcd/pkg/testutil"
+	"github.com/coreos/etcd/pkg/types"
+)
+
+func TestCtlV3MoveLeader(t *testing.T) {
+	defer testutil.AfterTest(t)
+
+	epc := setupEtcdctlTest(t, &configNoTLS, true)
+	defer func() {
+		if errC := epc.Close(); errC != nil {
+			t.Fatalf("error closing etcd processes (%v)", errC)
+		}
+	}()
+
+	var leadIdx int
+	var leaderID uint64
+	var transferee uint64
+	for i, ep := range epc.grpcEndpoints() {
+		cli, err := clientv3.New(clientv3.Config{
+			Endpoints:   []string{ep},
+			DialTimeout: 3 * time.Second,
+		})
+		if err != nil {
+			t.Fatal(err)
+		}
+		resp, err := cli.Status(context.Background(), ep)
+		if err != nil {
+			t.Fatal(err)
+		}
+		cli.Close()
+
+		if resp.Header.GetMemberId() == resp.Leader {
+			leadIdx = i
+			leaderID = resp.Leader
+		} else {
+			transferee = resp.Header.GetMemberId()
+		}
+	}
+
+	os.Setenv("ETCDCTL_API", "3")
+	defer os.Unsetenv("ETCDCTL_API")
+	cx := ctlCtx{
+		t:           t,
+		cfg:         configNoTLS,
+		dialTimeout: 7 * time.Second,
+		epc:         epc,
+	}
+
+	tests := []struct {
+		prefixes []string
+		expect   string
+	}{
+		{ // request to non-leader
+			cx.prefixArgs([]string{cx.epc.grpcEndpoints()[(leadIdx+1)%3]}),
+			"no leader endpoint given at ",
+		},
+		{ // request to leader
+			cx.prefixArgs([]string{cx.epc.grpcEndpoints()[leadIdx]}),
+			fmt.Sprintf("Leadership transferred from %s to %s", types.ID(leaderID), types.ID(transferee)),
+		},
+	}
+	for i, tc := range tests {
+		cmdArgs := append(tc.prefixes, "move-leader", types.ID(transferee).String())
+		if err := spawnWithExpect(cmdArgs, tc.expect); err != nil {
+			t.Fatalf("#%d: %v", i, err)
+		}
+	}
+}

etcdctl/README.md

@@ -805,6 +805,29 @@ Prints a line of JSON encoding the database hash, revision, total keys, and size
 +----------+----------+------------+------------+
 ```
 
+### MOVE-LEADER \<hexadecimal-transferee-id\>
+
+MOVE-LEADER manually transfers a leadership to another node in the cluster.
+
+#### Example
+
+```bash
+# to choose transferee
+transferee_id=$(./etcdctl \
+  --endpoints localhost:12379,localhost:22379,localhost:32379 \
+  endpoint status | grep -m 1 "false" | awk -F', ' '{print $2}')
+echo ${transferee_id}
+# c89feb932daef420
+
+# endpoints should include leader node
+./etcdctl --endpoints ${transferee_ep} move-leader ${transferee_id}
+# Error:  no leader endpoint given at [localhost:22379 localhost:32379]
+
+# request to leader with target node ID
+./etcdctl --endpoints ${leader_ep} move-leader ${transferee_id}
+# Leadership transferred from 45ddc0e800e20b93 to c89feb932daef420
+```
+
 ## Concurrency commands
 
 ### LOCK \<lockname\> [command arg1 arg2 ...]

etcdctl/ctlv3/command/move_leader_command.go

@@ -0,0 +1,90 @@
+// Copyright 2017 The etcd Authors
+//
+// 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 (
+	"fmt"
+	"strconv"
+	"time"
+
+	"github.com/coreos/etcd/clientv3"
+	"github.com/spf13/cobra"
+)
+
+// NewMoveLeaderCommand returns the cobra command for "move-leader".
+func NewMoveLeaderCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "move-leader <transferee>",
+		Short: "Transfers leadership.",
+		Run:   transferLeadershipCommandFunc,
+	}
+	return cmd
+}
+
+// transferLeadershipCommandFunc executes the "compaction" command.
+func transferLeadershipCommandFunc(cmd *cobra.Command, args []string) {
+	if len(args) != 1 {
+		ExitWithError(ExitBadArgs, fmt.Errorf("move-leader command needs 1 argument"))
+	}
+	target, err := strconv.ParseUint(args[0], 16, 64)
+	if err != nil {
+		ExitWithError(ExitBadArgs, err)
+	}
+
+	c := mustClientFromCmd(cmd)
+	eps := c.Endpoints()
+	c.Close()
+
+	ctx, cancel := commandCtx(cmd)
+
+	// find current leader
+	var leaderCli *clientv3.Client
+	var leaderID uint64
+	for _, ep := range eps {
+		cli, err := clientv3.New(clientv3.Config{
+			Endpoints:   []string{ep},
+			DialTimeout: 3 * time.Second,
+		})
+		if err != nil {
+			if err != nil {
+				ExitWithError(ExitError, err)
+			}
+		}
+		resp, err := cli.Status(ctx, ep)
+		if err != nil {
+			if err != nil {
+				ExitWithError(ExitError, err)
+			}
+		}
+
+		if resp.Header.GetMemberId() == resp.Leader {
+			leaderCli = cli
+			leaderID = resp.Leader
+		} else {
+			cli.Close()
+		}
+	}
+	if leaderCli == nil {
+		ExitWithError(ExitBadArgs, fmt.Errorf("no leader endpoint given at %v", eps))
+	}
+
+	cerr := leaderCli.MoveLeader(ctx, target)
+	cancel()
+	if cerr != nil {
+		ExitWithError(ExitError, cerr)
+	}
+
+	display.MoveLeader(leaderID, target)
+}

etcdctl/ctlv3/command/printer.go

@@ -43,6 +43,7 @@ type printer interface {
 	MemberList(v3.MemberListResponse)
 
 	EndpointStatus([]epStatus)
+	MoveLeader(leader, target uint64)
 
 	Alarm(v3.AlarmResponse)
 	DBStatus(dbstatus)
@@ -143,7 +144,10 @@ func newPrinterUnsupported(n string) printer {
 }
 
 func (p *printerUnsupported) EndpointStatus([]epStatus) { p.p(nil) }
-func (p *printerUnsupported) DBStatus(dbstatus)         { p.p(nil) }
+func (p *printerUnsupported) MoveLeader(leader, target uint64) {
+	p.p(nil)
+}
+func (p *printerUnsupported) DBStatus(dbstatus) { p.p(nil) }
 
 func makeMemberListTable(r v3.MemberListResponse) (hdr []string, rows [][]string) {
 	hdr = []string{"ID", "Status", "Name", "Peer Addrs", "Client Addrs"}

etcdctl/ctlv3/command/printer_simple.go

@@ -20,6 +20,7 @@ import (
 
 	v3 "github.com/coreos/etcd/clientv3"
 	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+	"github.com/coreos/etcd/pkg/types"
 )
 
 type simplePrinter struct {
@@ -135,6 +136,10 @@ func (s *simplePrinter) EndpointStatus(statusList []epStatus) {
 	}
 }
 
+func (s *simplePrinter) MoveLeader(leader, target uint64) {
+	fmt.Printf("Leadership transferred from %s to %s\n", types.ID(leader), types.ID(target))
+}
+
 func (s *simplePrinter) DBStatus(ds dbstatus) {
 	_, rows := makeDBStatusTable(ds)
 	for _, row := range rows {

etcdctl/ctlv3/ctl.go

@@ -82,6 +82,7 @@ func init() {
 		command.NewUserCommand(),
 		command.NewRoleCommand(),
 		command.NewCheckCommand(),
+		command.NewMoveLeaderCommand(),
 	)
 }