Add a json output to velero backup describe

Signed-off-by: allenxu404 <qix2@vmware.com>

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
 }

pkg/cmd/util/output/backup_structured_describer.go

@@ -0,0 +1,462 @@
+/*
+Copyright the Velero contributors.
+
+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 output
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	snapshotv1api "github.com/kubernetes-csi/external-snapshotter/client/v4/apis/volumesnapshot/v1"
+
+	kbclient "sigs.k8s.io/controller-runtime/pkg/client"
+
+	velerov1api "github.com/vmware-tanzu/velero/pkg/apis/velero/v1"
+	"github.com/vmware-tanzu/velero/pkg/cmd/util/downloadrequest"
+	"github.com/vmware-tanzu/velero/pkg/features"
+	clientset "github.com/vmware-tanzu/velero/pkg/generated/clientset/versioned"
+	"github.com/vmware-tanzu/velero/pkg/volume"
+)
+
+// DescribeBackupInSF describes a backup in structured format.
+func DescribeBackupInSF(
+	ctx context.Context,
+	kbClient kbclient.Client,
+	backup *velerov1api.Backup,
+	deleteRequests []velerov1api.DeleteBackupRequest,
+	podVolumeBackups []velerov1api.PodVolumeBackup,
+	volumeSnapshotContents []snapshotv1api.VolumeSnapshotContent,
+	details bool,
+	veleroClient clientset.Interface,
+	insecureSkipTLSVerify bool,
+	caCertFile string,
+	outputFormat string,
+) string {
+	return DescribeInSF(func(d *StructuredDescriber) {
+		d.DescribeMetadata(backup.ObjectMeta)
+
+		d.Describe("phase", backup.Status.Phase)
+
+		status := backup.Status
+		if len(status.ValidationErrors) > 0 {
+			d.Describe("validationErrors", status.ValidationErrors)
+		}
+
+		d.Describe("errors", status.Errors)
+		d.Describe("warnings", status.Warnings)
+
+		DescribeBackupSpecInSF(d, backup.Spec)
+
+		DescribeBackupStatusInSF(ctx, kbClient, d, backup, details, veleroClient, insecureSkipTLSVerify, caCertFile)
+
+		if len(deleteRequests) > 0 {
+			DescribeDeleteBackupRequestsInSF(d, deleteRequests)
+		}
+
+		if features.IsEnabled(velerov1api.CSIFeatureFlag) {
+			DescribeCSIVolumeSnapshotsInSF(d, details, volumeSnapshotContents)
+		}
+
+		if len(podVolumeBackups) > 0 {
+			DescribePodVolumeBackupsInSF(d, podVolumeBackups, details)
+		}
+	}, outputFormat)
+}
+
+// DescribeBackupSpecInSF describes a backup spec in structured format.
+func DescribeBackupSpecInSF(d *StructuredDescriber, spec velerov1api.BackupSpec) {
+	backupSpecInfo := make(map[string]interface{})
+	var s string
+
+	// describe namespaces
+	namespaceInfo := make(map[string]interface{})
+	if len(spec.IncludedNamespaces) == 0 {
+		s = "*"
+	} else {
+		s = strings.Join(spec.IncludedNamespaces, ", ")
+	}
+	namespaceInfo["included"] = s
+	if len(spec.ExcludedNamespaces) == 0 {
+		s = emptyDisplay
+	} else {
+		s = strings.Join(spec.ExcludedNamespaces, ", ")
+	}
+	namespaceInfo["excluded"] = s
+	backupSpecInfo["namespaces"] = namespaceInfo
+
+	// describe resources
+	resourcesInfo := make(map[string]string)
+	if len(spec.IncludedResources) == 0 {
+		s = "*"
+	} else {
+		s = strings.Join(spec.IncludedResources, ", ")
+	}
+	resourcesInfo["included"] = s
+
+	if len(spec.ExcludedResources) == 0 {
+		s = emptyDisplay
+	} else {
+		s = strings.Join(spec.ExcludedResources, ", ")
+	}
+	resourcesInfo["excluded"] = s
+	resourcesInfo["clusterScoped"] = BoolPointerString(spec.IncludeClusterResources, "excluded", "included", "auto")
+	backupSpecInfo["resources"] = resourcesInfo
+
+	// describe label selector
+	s = emptyDisplay
+	if spec.LabelSelector != nil {
+		s = metav1.FormatLabelSelector(spec.LabelSelector)
+	}
+	backupSpecInfo["labelSelector"] = s
+
+	// describe storage location
+	backupSpecInfo["storageLocation"] = spec.StorageLocation
+
+	// describe snapshot volumes
+	backupSpecInfo["veleroNativeSnapshotPVs"] = BoolPointerString(spec.SnapshotVolumes, "false", "true", "auto")
+
+	// describe TTL
+	backupSpecInfo["TTL"] = spec.TTL.Duration.String()
+
+	// describe CSI snapshot timeout
+	backupSpecInfo["CSISnapshotTimeout"] = spec.CSISnapshotTimeout.Duration.String()
+
+	// describe hooks
+	hooksInfo := make(map[string]interface{})
+	hooksResources := make(map[string]interface{})
+	for _, backupResourceHookSpec := range spec.Hooks.Resources {
+		ResourceDetails := make(map[string]interface{})
+		var s string
+		namespaceInfo := make(map[string]string)
+		if len(spec.IncludedNamespaces) == 0 {
+			s = "*"
+		} else {
+			s = strings.Join(spec.IncludedNamespaces, ", ")
+		}
+		namespaceInfo["included"] = s
+		if len(spec.ExcludedNamespaces) == 0 {
+			s = emptyDisplay
+		} else {
+			s = strings.Join(spec.ExcludedNamespaces, ", ")
+		}
+		namespaceInfo["excluded"] = s
+		ResourceDetails["namespaces"] = namespaceInfo
+
+		resourcesInfo := make(map[string]string)
+		if len(spec.IncludedResources) == 0 {
+			s = "*"
+		} else {
+			s = strings.Join(spec.IncludedResources, ", ")
+		}
+		resourcesInfo["included"] = s
+		if len(spec.ExcludedResources) == 0 {
+			s = emptyDisplay
+		} else {
+			s = strings.Join(spec.ExcludedResources, ", ")
+		}
+		resourcesInfo["excluded"] = s
+		ResourceDetails["resources"] = resourcesInfo
+
+		s = emptyDisplay
+		if backupResourceHookSpec.LabelSelector != nil {
+			s = metav1.FormatLabelSelector(backupResourceHookSpec.LabelSelector)
+		}
+		ResourceDetails["labelSelector"] = s
+
+		preHooks := make([]map[string]interface{}, 0)
+		for _, hook := range backupResourceHookSpec.PreHooks {
+			if hook.Exec != nil {
+				preExecHook := make(map[string]interface{})
+				preExecHook["container"] = hook.Exec.Container
+				preExecHook["command"] = strings.Join(hook.Exec.Command, " ")
+				preExecHook["onError:"] = hook.Exec.OnError
+				preExecHook["timeout"] = hook.Exec.Timeout.Duration.String()
+				preHooks = append(preHooks, preExecHook)
+			}
+		}
+		ResourceDetails["preExecHook"] = preHooks
+
+		postHooks := make([]map[string]interface{}, 0)
+		for _, hook := range backupResourceHookSpec.PostHooks {
+			if hook.Exec != nil {
+				postExecHook := make(map[string]interface{})
+				postExecHook["container"] = hook.Exec.Container
+				postExecHook["command"] = strings.Join(hook.Exec.Command, " ")
+				postExecHook["onError:"] = hook.Exec.OnError
+				postExecHook["timeout"] = hook.Exec.Timeout.Duration.String()
+				postHooks = append(postHooks, postExecHook)
+			}
+		}
+		ResourceDetails["postExecHook"] = postHooks
+		hooksResources[backupResourceHookSpec.Name] = ResourceDetails
+	}
+	if len(spec.Hooks.Resources) > 0 {
+		hooksInfo["resources"] = hooksResources
+		backupSpecInfo["hooks"] = hooksInfo
+	}
+
+	// desrcibe ordered resources
+	if spec.OrderedResources != nil {
+		backupSpecInfo["orderedResources"] = spec.OrderedResources
+	}
+
+	d.Describe("spec", backupSpecInfo)
+}
+
+// DescribeBackupStatusInSF describes a backup status in structured format.
+func DescribeBackupStatusInSF(ctx context.Context, kbClient kbclient.Client, d *StructuredDescriber, backup *velerov1api.Backup, details bool, veleroClient clientset.Interface, insecureSkipTLSVerify bool, caCertPath string) {
+	status := backup.Status
+	backupStatusInfo := make(map[string]interface{})
+
+	// Status.Version has been deprecated, use Status.FormatVersion
+	backupStatusInfo["backupFormatVersion"] = status.FormatVersion
+
+	// "<n/a>" output should only be applicable for backups that failed validation
+	if status.StartTimestamp == nil || status.StartTimestamp.Time.IsZero() {
+		backupStatusInfo["started"] = "<n/a>"
+	} else {
+		backupStatusInfo["started"] = status.StartTimestamp.Time.String()
+	}
+	if status.CompletionTimestamp == nil || status.CompletionTimestamp.Time.IsZero() {
+		backupStatusInfo["completed"] = "<n/a>"
+
+	} else {
+		backupStatusInfo["completed"] = status.CompletionTimestamp.Time.String()
+	}
+
+	// Expiration can't be 0, it is always set to a 30-day default. It can be nil
+	// if the controller hasn't processed this Backup yet, in which case this will
+	// just display `<nil>`, though this should be temporary.
+	backupStatusInfo["expiration"] = status.Expiration.String()
+
+	defer d.Describe("status", backupStatusInfo)
+
+	if backup.Status.Progress != nil {
+		if backup.Status.Phase == velerov1api.BackupPhaseInProgress {
+			backupStatusInfo["estimatedTotalItemsToBeBackedUp"] = backup.Status.Progress.TotalItems
+			backupStatusInfo["itemsBackedUpSoFar"] = backup.Status.Progress.ItemsBackedUp
+
+		} else {
+			backupStatusInfo["totalItemsToBeBackedUp"] = backup.Status.Progress.TotalItems
+			backupStatusInfo["itemsBackedUp"] = backup.Status.Progress.ItemsBackedUp
+		}
+	}
+
+	if details {
+		describeBackupResourceListInSF(ctx, kbClient, backupStatusInfo, backup, insecureSkipTLSVerify, caCertPath)
+	}
+
+	// In consideration of decoding structured output conveniently, the three separate fields were created here
+	// the field of "veleroNativeSnapshots" displays the brief snapshots info
+	// the field of "veleroNativeSnapshotsError" displays the error message if it fails to get snapshot info
+	// the field of "veleroNativeSnapshotsDetail" displays the detailed snapshots info
+	if status.VolumeSnapshotsAttempted > 0 {
+		if !details {
+			backupStatusInfo["veleroNativeSnapshots"] = fmt.Sprintf("%d of %d snapshots completed successfully", status.VolumeSnapshotsCompleted, status.VolumeSnapshotsAttempted)
+			return
+		}
+
+		buf := new(bytes.Buffer)
+		if err := downloadrequest.Stream(ctx, kbClient, backup.Namespace, backup.Name, velerov1api.DownloadTargetKindBackupVolumeSnapshots, buf, downloadRequestTimeout, insecureSkipTLSVerify, caCertPath); err != nil {
+			backupStatusInfo["veleroNativeSnapshotsError"] = fmt.Sprintf("<error getting snapshot info: %v>", err)
+			return
+		}
+
+		var snapshots []*volume.Snapshot
+		if err := json.NewDecoder(buf).Decode(&snapshots); err != nil {
+			backupStatusInfo["veleroNativeSnapshotsError"] = fmt.Sprintf("<error reading snapshot info: %v>", err)
+			return
+		}
+
+		snapshotDetails := make(map[string]interface{})
+		for _, snap := range snapshots {
+			describeSnapshotInSF(snap.Spec.PersistentVolumeName, snap.Status.ProviderSnapshotID, snap.Spec.VolumeType, snap.Spec.VolumeAZ, snap.Spec.VolumeIOPS, snapshotDetails)
+		}
+		backupStatusInfo["veleroNativeSnapshotsDetail"] = snapshotDetails
+		return
+	}
+
+}
+
+func describeBackupResourceListInSF(ctx context.Context, kbClient kbclient.Client, backupStatusInfo map[string]interface{}, backup *velerov1api.Backup, insecureSkipTLSVerify bool, caCertPath string) {
+	// In consideration of decoding structured output conveniently, the two separate fields were created here(in func describeBackupResourceList, there is only one field describing either error message or resource list)
+	// the field of 'resourceListError' gives specific error message when it fails to get resources list
+	// the field of 'resourceList' lists the rearranged resources
+	buf := new(bytes.Buffer)
+	if err := downloadrequest.Stream(ctx, kbClient, backup.Namespace, backup.Name, velerov1api.DownloadTargetKindBackupResourceList, buf, downloadRequestTimeout, insecureSkipTLSVerify, caCertPath); err != nil {
+		if err == downloadrequest.ErrNotFound {
+			// the backup resource list could be missing if (other reasons may exist as well):
+			//	- the backup was taken prior to v1.1; or
+			//	- the backup hasn't completed yet; or
+			//	- there was an error uploading the file; or
+			//	- the file was manually deleted after upload
+			backupStatusInfo["resourceListError"] = "<backup resource list not found>"
+		} else {
+			backupStatusInfo["resourceListError"] = fmt.Sprintf("<error getting backup resource list: %v>", err)
+		}
+		return
+	}
+
+	var resourceList map[string][]string
+	if err := json.NewDecoder(buf).Decode(&resourceList); err != nil {
+		backupStatusInfo["resourceListError"] = fmt.Sprintf("<error reading backup resource list: %v>\n", err)
+		return
+	}
+	backupStatusInfo["resourceList"] = resourceList
+}
+
+func describeSnapshotInSF(pvName, snapshotID, volumeType, volumeAZ string, iops *int64, snapshotDetails map[string]interface{}) {
+	snapshotInfo := make(map[string]string)
+	iopsString := "<N/A>"
+	if iops != nil {
+		iopsString = fmt.Sprintf("%d", *iops)
+	}
+
+	snapshotInfo["snapshotID"] = snapshotID
+	snapshotInfo["type"] = volumeType
+	snapshotInfo["availabilityZone"] = volumeAZ
+	snapshotInfo["IOPS"] = iopsString
+	snapshotDetails[pvName] = snapshotInfo
+
+}
+
+// DescribeDeleteBackupRequestsInSF describes delete backup requests in structured format.
+func DescribeDeleteBackupRequestsInSF(d *StructuredDescriber, requests []velerov1api.DeleteBackupRequest) {
+	deletionAttempts := make(map[string]interface{})
+	if count := failedDeletionCount(requests); count > 0 {
+		deletionAttempts["failed"] = count
+	}
+
+	deletionRequests := make([]map[string]interface{}, 0)
+	for _, req := range requests {
+		deletionReq := make(map[string]interface{})
+		deletionReq["creationTimestamp"] = req.CreationTimestamp.String()
+		deletionReq["phase"] = req.Status.Phase
+
+		if len(req.Status.Errors) > 0 {
+			deletionReq["errors"] = req.Status.Errors
+		}
+		deletionRequests = append(deletionRequests, deletionReq)
+	}
+	deletionAttempts["deleteBackupRequests"] = deletionRequests
+	d.Describe("deletionAttempts", deletionAttempts)
+}
+
+// DescribePodVolumeBackupsInSF describes pod volume backups in structured format.
+func DescribePodVolumeBackupsInSF(d *StructuredDescriber, backups []velerov1api.PodVolumeBackup, details bool) {
+	PodVolumeBackupsInfo := make(map[string]interface{})
+	// Get the type of pod volume uploader. Since the uploader only comes from a single source, we can
+	// take the uploader type from the first element of the array.
+	var uploaderType string
+	if len(backups) > 0 {
+		uploaderType = backups[0].Spec.UploaderType
+	} else {
+		return
+	}
+	// type display the type of pod volume backups
+	PodVolumeBackupsInfo["type"] = uploaderType
+
+	podVolumeBackupsDetails := make(map[string]interface{})
+	// separate backups by phase (combining <none> and New into a single group)
+	backupsByPhase := groupByPhase(backups)
+
+	// go through phases in a specific order
+	for _, phase := range []string{
+		string(velerov1api.PodVolumeBackupPhaseCompleted),
+		string(velerov1api.PodVolumeBackupPhaseFailed),
+		"In Progress",
+		string(velerov1api.PodVolumeBackupPhaseNew),
+	} {
+		if len(backupsByPhase[phase]) == 0 {
+			continue
+		}
+		// if we're not printing details, just report the phase and count
+		if !details {
+			podVolumeBackupsDetails[phase] = len(backupsByPhase[phase])
+			continue
+		}
+		// group the backups in the current phase by pod (i.e. "ns/name")
+		backupsByPod := new(volumesByPod)
+		for _, backup := range backupsByPhase[phase] {
+			backupsByPod.Add(backup.Spec.Pod.Namespace, backup.Spec.Pod.Name, backup.Spec.Volume, phase, backup.Status.Progress)
+		}
+
+		backupsByPods := make([]map[string]string, 0)
+		for _, backupGroup := range backupsByPod.volumesByPodSlice {
+			// print volumes backed up for this pod
+			backupsByPods = append(backupsByPods, map[string]string{backupGroup.label: strings.Join(backupGroup.volumes, ", ")})
+		}
+		podVolumeBackupsDetails[phase] = backupsByPods
+	}
+	// Pod Volume Backups Details display the detailed pod volume backups info
+	PodVolumeBackupsInfo["podVolumeBackupsDetails"] = podVolumeBackupsDetails
+	d.Describe("podVolumeBackups", PodVolumeBackupsInfo)
+}
+
+// DescribeCSIVolumeSnapshotsInSF describes CSI volume snapshots in structured format.
+func DescribeCSIVolumeSnapshotsInSF(d *StructuredDescriber, details bool, volumeSnapshotContents []snapshotv1api.VolumeSnapshotContent) {
+	CSIVolumeSnapshotsInfo := make(map[string]interface{})
+	if !features.IsEnabled(velerov1api.CSIFeatureFlag) {
+		return
+	}
+
+	if len(volumeSnapshotContents) == 0 {
+		return
+	}
+
+	// In consideration of decoding structured output conveniently, the two separate fields were created here
+	// the field of 'CSI Volume Snapshots Count' displays the count of CSI Volume Snapshots
+	// the field of 'CSI Volume Snapshots Details' displays the content of CSI Volume Snapshots
+	if !details {
+		CSIVolumeSnapshotsInfo["CSIVolumeSnapshotsCount"] = len(volumeSnapshotContents)
+		return
+	}
+
+	vscDetails := make(map[string]interface{})
+	for _, vsc := range volumeSnapshotContents {
+		DescribeVSCInSF(details, vsc, vscDetails)
+	}
+	CSIVolumeSnapshotsInfo["CSIVolumeSnapshotsDetails"] = vscDetails
+	d.Describe("CSIVolumeSnapshots", CSIVolumeSnapshotsInfo)
+}
+
+// DescribeVSCInSF describes CSI volume snapshot contents in structured format.
+func DescribeVSCInSF(details bool, vsc snapshotv1api.VolumeSnapshotContent, vscDetails map[string]interface{}) {
+	content := make(map[string]interface{})
+	if vsc.Status == nil {
+		vscDetails[vsc.Name] = content
+		return
+	}
+
+	if vsc.Status.SnapshotHandle != nil {
+		content["storageSnapshotID"] = *vsc.Status.SnapshotHandle
+	}
+
+	if vsc.Status.RestoreSize != nil {
+		content["snapshotSize(bytes)"] = *vsc.Status.RestoreSize
+
+	}
+
+	if vsc.Status.ReadyToUse != nil {
+		content["readyToUse"] = *vsc.Status.ReadyToUse
+	}
+	vscDetails[vsc.Name] = content
+}

pkg/cmd/util/output/describe.go

@@ -18,6 +18,7 @@ package output
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"sort"
 	"strings"
@@ -46,6 +47,15 @@ func Describe(fn func(d *Describer)) string {
 	return d.buf.String()
 }
 
+func NewDescriber(minwidth, tabwidth, padding int, padchar byte, flags uint) *Describer {
+	d := &Describer{
+		out: new(tabwriter.Writer),
+		buf: new(bytes.Buffer),
+	}
+	d.out.Init(d.buf, minwidth, tabwidth, padding, padchar, flags)
+	return d
+}
+
 func (d *Describer) Printf(msg string, args ...interface{}) {
 	fmt.Fprint(d.out, d.Prefix)
 	fmt.Fprintf(d.out, msg, args...)
@@ -119,3 +129,50 @@ func BoolPointerString(b *bool, falseString, trueString, nilString string) strin
 	}
 	return falseString
 }
+
+type StructuredDescriber struct {
+	output map[string]interface{}
+	format string
+}
+
+// NewStructuredDescriber creates a StructuredDescriber.
+func NewStructuredDescriber(format string) *StructuredDescriber {
+	return &StructuredDescriber{
+		output: make(map[string]interface{}),
+		format: format,
+	}
+}
+
+// DescribeInSF returns the structured output based on the func
+// that applies StructuredDescriber to collect outputs.
+// This function takes arg 'format' for future format extension.
+func DescribeInSF(fn func(d *StructuredDescriber), format string) string {
+	d := NewStructuredDescriber(format)
+	fn(d)
+	return d.JsonEncode()
+}
+
+// Describe adds all types of argument to d.output.
+func (d *StructuredDescriber) Describe(name string, arg interface{}) {
+	d.output[name] = arg
+}
+
+// DescribeMetadata describes standard object metadata.
+func (d *StructuredDescriber) DescribeMetadata(metadata metav1.ObjectMeta) {
+	metadataInfo := make(map[string]interface{})
+	metadataInfo["name"] = metadata.Name
+	metadataInfo["namespace"] = metadata.Namespace
+	metadataInfo["labels"] = metadata.Labels
+	metadataInfo["annotations"] = metadata.Annotations
+	d.Describe("metadata", metadataInfo)
+}
+
+// JsonEncode encodes d.output to json
+func (d *StructuredDescriber) JsonEncode() string {
+	byteBuffer := &bytes.Buffer{}
+	encoder := json.NewEncoder(byteBuffer)
+	encoder.SetEscapeHTML(false)
+	encoder.SetIndent("", "    ")
+	_ = encoder.Encode(d.output)
+	return byteBuffer.String()
+}