*: add learner field in endpoint status

Added learner field to endpoint status API.

etcdctl/ctlv3/command/ep_command.go

@@ -60,7 +60,7 @@ func newEpStatusCommand() *cobra.Command {
 		Use:   "status",
 		Short: "Prints out the status of endpoints specified in `--endpoints` flag",
 		Long: `When --write-out is set to simple, this command prints out comma-separated status lists for each endpoint.
-The items in the lists are endpoint, ID, version, db size, is leader, raft term, raft index.
+The items in the lists are endpoint, ID, version, db size, is leader, is learner, raft term, raft index, raft applied index, errors.
 `,
 		Run: epStatusCommandFunc,
 	}

etcdctl/ctlv3/command/printer.go

@@ -194,7 +194,8 @@ func makeEndpointHealthTable(healthList []epHealth) (hdr []string, rows [][]stri
 }
 
 func makeEndpointStatusTable(statusList []epStatus) (hdr []string, rows [][]string) {
-	hdr = []string{"endpoint", "ID", "version", "db size", "is leader", "raft term", "raft index", "raft applied index", "errors"}
+	hdr = []string{"endpoint", "ID", "version", "db size", "is leader", "is learner", "raft term",
+		"raft index", "raft applied index", "errors"}
 	for _, status := range statusList {
 		rows = append(rows, []string{
 			status.Ep,
@@ -202,6 +203,7 @@ func makeEndpointStatusTable(statusList []epStatus) (hdr []string, rows [][]stri
 			status.Resp.Version,
 			humanize.Bytes(uint64(status.Resp.DbSize)),
 			fmt.Sprint(status.Resp.Leader == status.Resp.Header.MemberId),
+			fmt.Sprint(status.Resp.IsLearner),
 			fmt.Sprint(status.Resp.RaftTerm),
 			fmt.Sprint(status.Resp.RaftIndex),
 			fmt.Sprint(status.Resp.RaftAppliedIndex),

etcdctl/ctlv3/command/printer_fields.go

@@ -158,6 +158,7 @@ func (p *fieldsPrinter) EndpointStatus(eps []epStatus) {
 		fmt.Printf("\"Version\" : %q\n", ep.Resp.Version)
 		fmt.Println(`"DBSize" :`, ep.Resp.DbSize)
 		fmt.Println(`"Leader" :`, ep.Resp.Leader)
+		fmt.Println(`"IsLearner" :`, ep.Resp.IsLearner)
 		fmt.Println(`"RaftIndex" :`, ep.Resp.RaftIndex)
 		fmt.Println(`"RaftTerm" :`, ep.Resp.RaftTerm)
 		fmt.Println(`"RaftAppliedIndex" :`, ep.Resp.RaftAppliedIndex)

etcdserver/api/membership/cluster.go

@@ -693,3 +693,22 @@ func mustDetectDowngrade(lg *zap.Logger, cv *semver.Version) {
 		}
 	}
 }
+
+// IsLearner returns if the local member is raft learner
+func (c *RaftCluster) IsLearner() bool {
+	c.Lock()
+	defer c.Unlock()
+	localMember, ok := c.members[c.localID]
+	if !ok {
+		if c.lg != nil {
+			c.lg.Panic(
+				"failed to find local ID in cluster members",
+				zap.String("cluster-id", c.cid.String()),
+				zap.String("local-member-id", c.localID.String()),
+			)
+		} else {
+			plog.Panicf("failed to find local ID %s in cluster %s", c.localID.String(), c.cid.String())
+		}
+	}
+	return localMember.IsLearner
+}

etcdserver/api/v3rpc/maintenance.go

@@ -55,6 +55,10 @@ type AuthGetter interface {
 	AuthStore() auth.AuthStore
 }
 
+type ClusterStatusGetter interface {
+	IsLearner() bool
+}
+
 type maintenanceServer struct {
 	lg  *zap.Logger
 	rg  etcdserver.RaftStatusGetter
@@ -63,10 +67,11 @@ type maintenanceServer struct {
 	a   Alarmer
 	lt  LeaderTransferrer
 	hdr header
+	cs  ClusterStatusGetter
 }
 
 func NewMaintenanceServer(s *etcdserver.EtcdServer) pb.MaintenanceServer {
-	srv := &maintenanceServer{lg: s.Cfg.Logger, rg: s, kg: s, bg: s, a: s, lt: s, hdr: newHeader(s)}
+	srv := &maintenanceServer{lg: s.Cfg.Logger, rg: s, kg: s, bg: s, a: s, lt: s, hdr: newHeader(s), cs: s}
 	return &authMaintenanceServer{srv, s}
 }
 
@@ -179,6 +184,7 @@ func (ms *maintenanceServer) Status(ctx context.Context, ar *pb.StatusRequest) (
 		RaftTerm:         ms.rg.Term(),
 		DbSize:           ms.bg.Backend().Size(),
 		DbSizeInUse:      ms.bg.Backend().SizeInUse(),
+		IsLearner:        ms.cs.IsLearner(),
 	}
 	if resp.Leader == raft.None {
 		resp.Errors = append(resp.Errors, etcdserver.ErrNoLeader.Error())

etcdserver/server.go

@@ -2440,3 +2440,8 @@ func (s *EtcdServer) Alarms() []*pb.AlarmMember {
 func (s *EtcdServer) Logger() *zap.Logger {
 	return s.lg
 }
+
+// IsLearner returns if the local member is raft learner
+func (s *EtcdServer) IsLearner() bool {
+	return s.cluster.IsLearner()
+}