etcdctl: add learner field in member list output

etcdctl/ctlv3/command/member_command.go

@@ -90,7 +90,7 @@ func NewMemberListCommand() *cobra.Command {
 		Use:   "list",
 		Short: "Lists all members in the cluster",
 		Long: `When --write-out is set to simple, this command prints out comma-separated member lists for each endpoint.
-The items in the lists are ID, Status, Name, Peer Addrs, Client Addrs.
+The items in the lists are ID, Status, Name, Peer Addrs, Client Addrs, Is Learner.
 `,
 
 		Run: memberListCommandFunc,

etcdctl/ctlv3/command/printer.go

@@ -158,18 +158,23 @@ func (p *printerUnsupported) DBStatus(snapshot.Status)  { p.p(nil) }
 func (p *printerUnsupported) MoveLeader(leader, target uint64, r v3.MoveLeaderResponse) { p.p(nil) }
 
 func makeMemberListTable(r v3.MemberListResponse) (hdr []string, rows [][]string) {
-	hdr = []string{"ID", "Status", "Name", "Peer Addrs", "Client Addrs"}
+	hdr = []string{"ID", "Status", "Name", "Peer Addrs", "Client Addrs", "Is Learner"}
 	for _, m := range r.Members {
 		status := "started"
 		if len(m.Name) == 0 {
 			status = "unstarted"
 		}
+		isLearner := "false"
+		if m.IsLearner {
+			isLearner = "true"
+		}
 		rows = append(rows, []string{
 			fmt.Sprintf("%x", m.ID),
 			status,
 			m.Name,
 			strings.Join(m.PeerURLs, ","),
 			strings.Join(m.ClientURLs, ","),
+			isLearner,
 		})
 	}
 	return hdr, rows

etcdctl/ctlv3/command/printer_fields.go

@@ -137,6 +137,7 @@ func (p *fieldsPrinter) MemberList(r v3.MemberListResponse) {
 		for _, u := range m.ClientURLs {
 			fmt.Printf("\"ClientURL\" : %q\n", u)
 		}
+		fmt.Println(`"IsLearner" :`, m.IsLearner)
 		fmt.Println()
 	}
 }