etcdctl/ctlv3: add 'transfer-leadership'

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

e2e/ctl_v3_transfer_leadership_test.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 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 TestCtlV3TransferLeadership(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 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
+		} 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]}),
+			"etcdserver: not a leader",
+		},
+		{ // request to leader
+			cx.prefixArgs([]string{cx.epc.grpcEndpoints()[leadIdx]}),
+			fmt.Sprintf("leader transferred to %s", types.ID(transferee)),
+		},
+	}
+	for i, tc := range tests {
+		cmdArgs := append(tc.prefixes, "transfer-leadership", types.ID(transferee).String())
+		if err := spawnWithExpect(cmdArgs, tc.expect); err != nil {
+			t.Fatalf("#%d: %v", i, err)
+		}
+	}
+}

etcdctl/README.md

@@ -788,6 +788,35 @@ Prints a line of JSON encoding the database hash, revision, total keys, and size
 +----------+----------+------------+------------+
 ```
 
+### TRANSFER-LEADERSHIP \<hexadecimal-transferee-id\>
+
+TRANSFER-LEADERSHIP manually transfers a leadership to another node in the cluster.
+
+#### Example
+
+```bash
+# to get leader endpoint
+leader_ep=$(./etcdctl \
+  --endpoints localhost:12379,localhost:22379,localhost:32379 \
+  endpoint status | grep -m 1 "true" | awk -F', ' '{print $1}')
+echo leader_ep: ${leader_ep}
+
+# to choose transferee
+transferee_id=$(./etcdctl \
+  --endpoints localhost:12379,localhost:22379,localhost:32379 \
+  endpoint status | grep -m 1 "false" | awk -F', ' '{print $2}')
+echo ${transferee_id}
+# c89feb932daef420
+
+# request to follower should fail
+./etcdctl --endpoints ${transferee_ep} transfer-leadership ${transferee_id}
+# Error:  etcdserver: not a leader
+
+# request to leader with follower node ID
+./etcdctl --endpoints ${leader_ep} transfer-leadership ${transferee_id}
+# leader transferred to c89feb932daef420
+```
+
 ## Concurrency commands
 
 ### LOCK \<lockname\> [command arg1 arg2 ...]

etcdctl/ctlv3/command/transfer_leadership_command.go

@@ -0,0 +1,55 @@
+// 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"
+
+	"github.com/coreos/etcd/pkg/types"
+	"github.com/spf13/cobra"
+)
+
+// NewTransferLeadershipCommand returns the cobra command for "transfer-leadership".
+func NewTransferLeadershipCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "transfer-leadership <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("transfer-leadership command needs 1 argument"))
+	}
+
+	transferee, err := strconv.ParseUint(args[0], 16, 64)
+	if err != nil {
+		ExitWithError(ExitError, err)
+	}
+
+	c := mustClientFromCmd(cmd)
+	ctx, cancel := commandCtx(cmd)
+	cerr := c.TransferLeadership(ctx, transferee)
+	cancel()
+	if cerr != nil {
+		ExitWithError(ExitError, cerr)
+		return
+	}
+	fmt.Printf("leader transferred to %s\n", types.ID(transferee))
+}

etcdctl/ctlv3/ctl.go

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