ctlv3: print cluster info after adding new member

etcdctl/README.md

@@ -468,7 +468,12 @@ Prints the member ID of the new member and the cluster ID.
 
 ```bash
 ./etcdctl member add newMember --peer-urls=https://127.0.0.1:12345
-# Member 2be1eb8f84b7f63e added to cluster ef37ad9dc622a7c4
+
+Member ced000fda4d05edf added to cluster 8c4281cc65c7b112
+
+ETCD_NAME="newMember"
+ETCD_INITIAL_CLUSTER="newMember=https://127.0.0.1:12345,default=http://10.0.0.30:2380"
+ETCD_INITIAL_CLUSTER_STATE="existing"
 ```
 
 ### MEMBER UPDATE \<memberID\> [options]

etcdctl/ctlv3/command/member_command.go

@@ -99,6 +99,7 @@ func memberAddCommandFunc(cmd *cobra.Command, args []string) {
 	if len(args) != 1 {
 		ExitWithError(ExitBadArgs, fmt.Errorf("member name not provided."))
 	}
+	newMemberName := args[0]
 
 	if len(memberPeerURLs) == 0 {
 		ExitWithError(ExitBadArgs, fmt.Errorf("member peer urls not provided."))
@@ -111,8 +112,35 @@ func memberAddCommandFunc(cmd *cobra.Command, args []string) {
 	if err != nil {
 		ExitWithError(ExitError, err)
 	}
+	newID := resp.Member.ID
 
 	display.MemberAdd(*resp)
+
+	if _, ok := (display).(*simplePrinter); ok {
+		ctx, cancel = commandCtx(cmd)
+		listResp, err := mustClientFromCmd(cmd).MemberList(ctx)
+		cancel()
+
+		if err != nil {
+			ExitWithError(ExitError, err)
+		}
+
+		conf := []string{}
+		for _, memb := range listResp.Members {
+			for _, u := range memb.PeerURLs {
+				n := memb.Name
+				if memb.ID == newID {
+					n = newMemberName
+				}
+				conf = append(conf, fmt.Sprintf("%s=%s", n, u))
+			}
+		}
+
+		fmt.Print("\n")
+		fmt.Printf("ETCD_NAME=%q\n", newMemberName)
+		fmt.Printf("ETCD_INITIAL_CLUSTER=%q\n", strings.Join(conf, ","))
+		fmt.Printf("ETCD_INITIAL_CLUSTER_STATE=\"existing\"\n")
+	}
 }
 
 // memberRemoveCommandFunc executes the "member remove" command.