Add a json output to velero backup describe

changelogs/unreleased/5865-allenxu404

@@ -0,0 +1 @@
+Add a json output to cmd velero backup describe 

pkg/cmd/cli/backup/describe.go

@@ -41,6 +41,7 @@ func NewDescribeCommand(f client.Factory, use string) *cobra.Command {
 		listOptions           metav1.ListOptions
 		details               bool
 		insecureSkipTLSVerify bool
+		outputFormat          = "plaintext"
 	)
 
 	config, err := client.LoadConfig()
@@ -59,6 +60,10 @@ func NewDescribeCommand(f client.Factory, use string) *cobra.Command {
 			kbClient, err := f.KubebuilderClient()
 			cmd.CheckError(err)
 
+			if outputFormat != "plaintext" && outputFormat != "json" {
+				cmd.CheckError(fmt.Errorf("Invalid output format '%s'. Valid value are 'plaintext, json'", outputFormat))
+			}
+
 			var backups *velerov1api.BackupList
 			if len(args) > 0 {
 				backups = new(velerov1api.BackupList)
@@ -102,13 +107,21 @@ func NewDescribeCommand(f client.Factory, use string) *cobra.Command {
 					}
 				}
 
-				s := output.DescribeBackup(context.Background(), kbClient, &backups.Items[i], deleteRequestList.Items, podVolumeBackupList.Items, vscList.Items, details, veleroClient, insecureSkipTLSVerify, caCertFile)
-				if first {
-					first = false
+				// structured output only applies to a single backup in case of OOM
+				// To describe the list of backups in structured format, users could iterate over the list and describe backup one after another.
+				if len(backups.Items) == 1 && outputFormat != "plaintext" {
+					s := output.DescribeBackupInSF(context.Background(), kbClient, &backups.Items[i], deleteRequestList.Items, podVolumeBackupList.Items, vscList.Items, details, veleroClient, insecureSkipTLSVerify, caCertFile, outputFormat)
 					fmt.Print(s)
 				} else {
-					fmt.Printf("\n\n%s", s)
+					s := output.DescribeBackup(context.Background(), kbClient, &backups.Items[i], deleteRequestList.Items, podVolumeBackupList.Items, vscList.Items, details, veleroClient, insecureSkipTLSVerify, caCertFile)
+					if first {
+						first = false
+						fmt.Print(s)
+					} else {
+						fmt.Printf("\n\n%s", s)
+					}
 				}
+
 			}
 			cmd.CheckError(err)
 		},
@@ -118,5 +131,7 @@ func NewDescribeCommand(f client.Factory, use string) *cobra.Command {
 	c.Flags().BoolVar(&details, "details", details, "Display additional detail in the command output.")
 	c.Flags().BoolVar(&insecureSkipTLSVerify, "insecure-skip-tls-verify", insecureSkipTLSVerify, "If true, the object store's TLS certificate will not be checked for validity. This is insecure and susceptible to man-in-the-middle attacks. Not recommended for production.")
 	c.Flags().StringVar(&caCertFile, "cacert", caCertFile, "Path to a certificate bundle to use when verifying TLS connections.")
+	c.Flags().StringVarP(&outputFormat, "output", "o", outputFormat, "Output display format. Valid formats are 'plaintext, json'. 'json' only applies to a single backup")
+
 	return c
 }