volume.go

package set

import (
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"os"
	"path"
	"strings"

	"github.com/spf13/cobra"

	kapi "k8s.io/kubernetes/pkg/api"
	apierrs "k8s.io/kubernetes/pkg/api/errors"
	"k8s.io/kubernetes/pkg/api/meta"
	kresource "k8s.io/kubernetes/pkg/api/resource"
	"k8s.io/kubernetes/pkg/api/unversioned"
	kclient "k8s.io/kubernetes/pkg/client/unversioned"
	"k8s.io/kubernetes/pkg/kubectl"
	kcmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
	"k8s.io/kubernetes/pkg/kubectl/resource"
	"k8s.io/kubernetes/pkg/labels"
	"k8s.io/kubernetes/pkg/runtime"

	cmdutil "github.com/openshift/origin/pkg/cmd/util"
	"github.com/openshift/origin/pkg/cmd/util/clientcmd"
)

const (
	volumeLong = `
Update volumes on a pod template

This command can add, update or remove volumes from containers for any object
that has a pod template (deployment configs, replication controllers, or pods).
You can list volumes in pod or any object that has a pod template. You can
specify a single object or multiple, and alter volumes on all containers or
just those that match a given name.

If you alter a volume setting on a deployment config, a deployment will be
triggered. Changing a replication controller will not affect running pods, and
you cannot change a pod's volumes once it has been created.

Volume types include:

* emptydir (empty directory) *default*
    A directory allocated when the pod is created on a local host, is removed when
    the pod is deleted and is not copied across servers
* hostdir (host directory)
    A directory with specific path on any host (requires elevated privileges)
* persistentvolumeclaim or pvc (persistent volume claim)
    Link the volume directory in the container to a persistent volume claim you have
    allocated by name - a persistent volume claim is a request to allocate storage.
    Note that if your claim hasn't been bound, your pods will not start.
* secret (mounted secret)
    Secret volumes mount a named secret to the provided directory.

For descriptions on other volume types, see https://docs.openshift.com`

	volumeExample = `  # List volumes defined on all deployment configs in the current project
  $ %[1]s volume dc --all

  # Add a new empty dir volume to deployment config (dc) 'registry' mounted under
  # /var/lib/registry
  $ %[1]s volume dc/registry --add --mount-path=/var/lib/registry

  # Use an existing persistent volume claim (pvc) to overwrite an existing volume 'v1'
  $ %[1]s volume dc/registry --add --name=v1 -t pvc --claim-name=pvc1 --overwrite

  # Remove volume 'v1' from deployment config 'registry'
  $ %[1]s volume dc/registry --remove --name=v1

  # Create a new persistent volume claim that overwrites an existing volume 'v1'
  $ %[1]s volume dc/registry --add --name=v1 -t pvc --claim-size=1G --overwrite

  # Change the mount point for volume 'v1' to /data
  $ %[1]s volume dc/registry --add --name=v1 -m /data --overwrite

  # Modify the deployment config by removing volume mount "v1" from container "c1"
  # (and by removing the volume "v1" if no other containers have volume mounts that reference it)
  $ %[1]s volume dc/registry --remove --name=v1 --containers=c1

  # Add new volume based on a more complex volume source (Git repo, AWS EBS, GCE PD,
  # Ceph, Gluster, NFS, ISCSI, ...)
  $ %[1]s volume dc/registry --add -m /repo --source=<json-string>`

	volumePrefix = "volume-"
)

type VolumeOptions struct {
	DefaultNamespace       string
	ExplicitNamespace      bool
	Out                    io.Writer
	Err                    io.Writer
	Mapper                 meta.RESTMapper
	Typer                  runtime.ObjectTyper
	RESTClientFactory      func(mapping *meta.RESTMapping) (resource.RESTClient, error)
	UpdatePodSpecForObject func(obj runtime.Object, fn func(*kapi.PodSpec) error) (bool, error)
	Client                 kclient.PersistentVolumeClaimsNamespacer

	// Resource selection
	Selector  string
	All       bool
	Filenames []string

	// Operations
	Add    bool
	Remove bool
	List   bool

	// Common optional params
	Name          string
	Containers    string
	Confirm       bool
	Output        string
	OutputVersion unversioned.GroupVersion

	// Add op params
	AddOpts *AddVolumeOptions
}

type AddVolumeOptions struct {
	Type       string
	MountPath  string
	Overwrite  bool
	Path       string
	SecretName string
	Source     string

	CreateClaim bool
	ClaimName   string
	ClaimSize   string
	ClaimMode   string

	TypeChanged bool
}

func NewCmdVolume(fullName string, f *clientcmd.Factory, out, errOut io.Writer) *cobra.Command {
	addOpts := &AddVolumeOptions{}
	opts := &VolumeOptions{AddOpts: addOpts}
	cmd := &cobra.Command{
		Use:     "volumes RESOURCE/NAME --add|--remove|--list",
		Short:   "Update volumes on a pod template",
		Long:    volumeLong,
		Example: fmt.Sprintf(volumeExample, fullName),
		Aliases: []string{"volume"},
		Run: func(cmd *cobra.Command, args []string) {
			addOpts.TypeChanged = cmd.Flag("type").Changed

			err := opts.Validate(args)
			if err != nil {
				kcmdutil.CheckErr(kcmdutil.UsageError(cmd, err.Error()))
			}
			err = opts.Complete(f, cmd, out, errOut)
			kcmdutil.CheckErr(err)

			err = opts.RunVolume(args)
			if err == cmdutil.ErrExit {
				os.Exit(1)
			}
			kcmdutil.CheckErr(err)
		},
	}
	cmd.Flags().StringVarP(&opts.Selector, "selector", "l", "", "Selector (label query) to filter on")
	cmd.Flags().BoolVar(&opts.All, "all", false, "select all resources in the namespace of the specified resource types")
	cmd.Flags().StringSliceVarP(&opts.Filenames, "filename", "f", opts.Filenames, "Filename, directory, or URL to file to use to edit the resource.")
	cmd.Flags().BoolVar(&opts.Add, "add", false, "Add volume and/or volume mounts for containers")
	cmd.Flags().BoolVar(&opts.Remove, "remove", false, "Remove volume and/or volume mounts for containers")
	cmd.Flags().BoolVar(&opts.List, "list", false, "List volumes and volume mounts for containers")

	cmd.Flags().StringVar(&opts.Name, "name", "", "Name of the volume. If empty, auto generated for add operation")
	cmd.Flags().StringVarP(&opts.Containers, "containers", "c", "*", "The names of containers in the selected pod templates to change - may use wildcards")
	cmd.Flags().BoolVar(&opts.Confirm, "confirm", false, "Confirm that you really want to remove multiple volumes")
	cmd.Flags().StringVarP(&opts.Output, "output", "o", "", "Display the changed objects instead of updating them. One of: json|yaml")
	cmd.Flags().String("output-version", "", "Output the changed objects with the given version (default api-version).")

	cmd.Flags().StringVarP(&addOpts.Type, "type", "t", "", "Type of the volume source for add operation. Supported options: emptyDir, hostPath, secret, persistentVolumeClaim")
	cmd.Flags().StringVarP(&addOpts.MountPath, "mount-path", "m", "", "Mount path inside the container. Optional param for --add or --remove")
	cmd.Flags().BoolVar(&addOpts.Overwrite, "overwrite", false, "If true, replace existing volume source and/or volume mount for the given resource")
	cmd.Flags().StringVar(&addOpts.Path, "path", "", "Host path. Must be provided for hostPath volume type")
	cmd.Flags().StringVar(&addOpts.SecretName, "secret-name", "", "Name of the persisted secret. Must be provided for secret volume type")
	cmd.Flags().StringVar(&addOpts.ClaimName, "claim-name", "", "Persistent volume claim name. Must be provided for persistentVolumeClaim volume type")
	cmd.Flags().StringVar(&addOpts.ClaimSize, "claim-size", "", "If specified along with a persistent volume type, create a new claim with the given size in bytes. Accepts SI notation: 10, 10G, 10Gi")
	cmd.Flags().StringVar(&addOpts.ClaimMode, "claim-mode", "ReadWriteOnce", "Set the access mode of the claim to be created. Valid values are ReadWriteOnce (rwo), ReadWriteMany (rwm), or ReadOnlyMany (rom)")
	cmd.Flags().StringVar(&addOpts.Source, "source", "", "Details of volume source as json string. This can be used if the required volume type is not supported by --type option. (e.g.: '{\"gitRepo\": {\"repository\": <git-url>, \"revision\": <commit-hash>}}')")

	cmd.MarkFlagFilename("filename", "yaml", "yml", "json")

	return cmd
}

func (v *VolumeOptions) Validate(args []string) error {
	if len(v.Selector) > 0 {
		if _, err := labels.Parse(v.Selector); err != nil {
			return errors.New("--selector=<selector> must be a valid label selector")
		}
		if v.All {
			return errors.New("you may specify either --selector or --all but not both")
		}
	}
	if len(v.Filenames) == 0 && len(args) < 1 {
		return errors.New("provide one or more resources to add, list, or delete volumes on as TYPE/NAME")
	}

	numOps := 0
	if v.Add {
		numOps++
	}
	if v.Remove {
		numOps++
	}
	if v.List {
		numOps++
	}

	switch {
	case numOps == 0:
		v.List = true
	case numOps > 1:
		return errors.New("you may only specify one operation at a time")
	}

	if v.List && len(v.Output) > 0 {
		return errors.New("--list and --output may not be specified together")
	}

	err := v.AddOpts.Validate(v.Add)
	if err != nil {
		return err
	}
	// Removing all volumes for the resource type needs confirmation
	if v.Remove && len(v.Name) == 0 && !v.Confirm {
		return errors.New("must provide --confirm for removing more than one volume")
	}
	return nil
}

func (a *AddVolumeOptions) Validate(isAddOp bool) error {
	if isAddOp {
		if len(a.Type) == 0 && (len(a.ClaimName) > 0 || len(a.ClaimSize) > 0) {
			a.Type = "persistentvolumeclaim"
			a.TypeChanged = true
		}

		if len(a.Type) == 0 {
			a.Type = "emptydir"
		}

		if len(a.Type) == 0 && len(a.Source) == 0 {
			return errors.New("must provide --type or --source for --add operation")
		} else if a.TypeChanged && len(a.Source) > 0 {
			return errors.New("either specify --type or --source but not both for --add operation")
		}

		if len(a.Type) > 0 {
			switch strings.ToLower(a.Type) {
			case "emptydir":
			case "hostpath":
				if len(a.Path) == 0 {
					return errors.New("must provide --path for --type=hostPath")
				}
			case "secret":
				if len(a.SecretName) == 0 {
					return errors.New("must provide --secret-name for --type=secret")
				}
			case "persistentvolumeclaim", "pvc":
				if len(a.ClaimName) == 0 && len(a.ClaimSize) == 0 {
					return errors.New("must provide --claim-name or --claim-size (to create a new claim) for --type=pvc")
				}
			default:
				return errors.New("invalid volume type. Supported types: emptyDir, hostPath, secret, persistentVolumeClaim")
			}
		} else if len(a.Path) > 0 || len(a.SecretName) > 0 || len(a.ClaimName) > 0 {
			return errors.New("--path|--secret-name|--claim-name are only valid for --type option")
		}

		if len(a.Source) > 0 {
			var source map[string]interface{}
			err := json.Unmarshal([]byte(a.Source), &source)
			if err != nil {
				return err
			}
			if len(source) > 1 {
				return errors.New("must provide only one volume for --source")
			}

			var vs kapi.VolumeSource
			err = json.Unmarshal([]byte(a.Source), &vs)
			if err != nil {
				return err
			}
		}
	} else if len(a.Source) > 0 || len(a.Path) > 0 || len(a.SecretName) > 0 || len(a.ClaimName) > 0 || a.Overwrite {
		return errors.New("--type|--path|--secret-name|--claim-name|--source|--overwrite are only valid for --add operation")
	}
	return nil
}

func (v *VolumeOptions) Complete(f *clientcmd.Factory, cmd *cobra.Command, out, errOut io.Writer) error {
	clientConfig, err := f.ClientConfig()
	if err != nil {
		return err
	}
	v.OutputVersion, err = kcmdutil.OutputVersion(cmd, clientConfig.GroupVersion)
	if err != nil {
		return err
	}
	_, kc, err := f.Clients()
	if err != nil {
		return err
	}
	v.Client = kc

	cmdNamespace, explicit, err := f.DefaultNamespace()
	if err != nil {
		return err
	}
	mapper, typer := f.Object()

	v.DefaultNamespace = cmdNamespace
	v.ExplicitNamespace = explicit
	v.Out = out
	v.Err = errOut
	v.Mapper = mapper
	v.Typer = typer
	v.RESTClientFactory = f.Factory.ClientForMapping
	v.UpdatePodSpecForObject = f.UpdatePodSpecForObject

	// In case of volume source ignore the default volume type
	if len(v.AddOpts.Source) > 0 {
		v.AddOpts.Type = ""
	}
	if len(v.AddOpts.ClaimSize) > 0 {
		v.AddOpts.CreateClaim = true
		if len(v.AddOpts.ClaimName) == 0 {
			v.AddOpts.ClaimName = kapi.SimpleNameGenerator.GenerateName("pvc-")
		}
		q, err := kresource.ParseQuantity(v.AddOpts.ClaimSize)
		if err != nil {
			return fmt.Errorf("--claim-size is not valid: %v", err)
		}
		v.AddOpts.ClaimSize = q.String()
	}
	switch strings.ToLower(v.AddOpts.ClaimMode) {
	case strings.ToLower(string(kapi.ReadOnlyMany)), "rom":
		v.AddOpts.ClaimMode = string(kapi.ReadOnlyMany)
	case strings.ToLower(string(kapi.ReadWriteOnce)), "rwo":
		v.AddOpts.ClaimMode = string(kapi.ReadWriteOnce)
	case strings.ToLower(string(kapi.ReadWriteMany)), "rwm":
		v.AddOpts.ClaimMode = string(kapi.ReadWriteMany)
	case "":
	default:
		return errors.New("--claim-mode must be one of ReadWriteOnce (rwo), ReadWriteMany (rwm), or ReadOnlyMany (rom)")
	}
	return nil
}

func (v *VolumeOptions) RunVolume(args []string) error {
	mapper := resource.ClientMapperFunc(v.RESTClientFactory)
	b := resource.NewBuilder(v.Mapper, v.Typer, mapper, kapi.Codecs.UniversalDecoder()).
		ContinueOnError().
		NamespaceParam(v.DefaultNamespace).DefaultNamespace().
		FilenameParam(v.ExplicitNamespace, v.Filenames...).
		SelectorParam(v.Selector).
		ResourceTypeOrNameArgs(v.All, args...).
		Flatten()

	singular := false
	infos, err := b.Do().IntoSingular(&singular).Infos()
	if err != nil {
		return err
	}

	updateInfos := []*resource.Info{}
	// if a claim should be created, generate the info we'll add to the flow
	if v.Add && v.AddOpts.CreateClaim {
		claim := v.AddOpts.createClaim()
		m, err := v.Mapper.RESTMapping(kapi.Kind("PersistentVolumeClaim"))
		if err != nil {
			return err
		}
		client, err := mapper.ClientForMapping(m)
		if err != nil {
			return err
		}
		info := &resource.Info{
			Mapping:   m,
			Client:    client,
			Namespace: v.DefaultNamespace,
			Object:    claim,
		}
		infos = append(infos, info)
		updateInfos = append(updateInfos, info)
	}

	skipped := 0
	for _, info := range infos {
		ok, err := v.UpdatePodSpecForObject(info.Object, func(spec *kapi.PodSpec) error {
			var e error
			switch {
			case v.Add:
				e = v.addVolumeToSpec(spec, info, singular)
			case v.Remove:
				e = v.removeVolumeFromSpec(spec, info)
			case v.List:
				e = v.listVolumeForSpec(spec, info)
			}
			return e
		})
		if !ok {
			skipped++
			continue
		}
		if err != nil {
			fmt.Fprintf(v.Err, "error: %s/%s %v\n", info.Mapping.Resource, info.Name, err)
			continue
		}
		updateInfos = append(updateInfos, info)
	}
	if singular && skipped == len(infos) {
		return fmt.Errorf("the %s %s is not a pod or does not have a pod template", infos[0].Mapping.Resource, infos[0].Name)
	}
	updatePodSpecFailed := len(updateInfos) != len(infos)

	if v.List {
		if updatePodSpecFailed {
			return cmdutil.ErrExit
		}
		return nil
	}

	// TODO: replace with a strategic merge patch
	objects, err := resource.AsVersionedObject(infos, false, v.OutputVersion.String(), kapi.Codecs.LegacyCodec(v.OutputVersion))
	if err != nil {
		return err
	}

	if len(v.Output) != 0 {
		p, _, err := kubectl.GetPrinter(v.Output, "")
		if err != nil {
			return err
		}
		return p.PrintObj(objects, v.Out)
	}

	failed := false
	for _, info := range updateInfos {
		var obj runtime.Object
		if len(info.ResourceVersion) == 0 {
			obj, err = resource.NewHelper(info.Client, info.Mapping).Create(info.Namespace, false, info.Object)
		} else {
			obj, err = resource.NewHelper(info.Client, info.Mapping).Replace(info.Namespace, info.Name, true, info.Object)
		}
		if err != nil {
			handlePodUpdateError(v.Err, err, "volume")
			failed = true
			continue
		}
		info.Refresh(obj, true)
		fmt.Fprintf(v.Out, "%s/%s\n", info.Mapping.Resource, info.Name)
	}
	if failed || updatePodSpecFailed {
		return cmdutil.ErrExit
	}
	return nil
}

func setVolumeSourceByType(kv *kapi.Volume, opts *AddVolumeOptions) error {
	switch strings.ToLower(opts.Type) {
	case "emptydir":
		kv.EmptyDir = &kapi.EmptyDirVolumeSource{}
	case "hostpath":
		kv.HostPath = &kapi.HostPathVolumeSource{
			Path: opts.Path,
		}
	case "secret":
		kv.Secret = &kapi.SecretVolumeSource{
			SecretName: opts.SecretName,
		}
	case "persistentvolumeclaim", "pvc":
		kv.PersistentVolumeClaim = &kapi.PersistentVolumeClaimVolumeSource{
			ClaimName: opts.ClaimName,
		}
	default:
		return fmt.Errorf("invalid volume type: %s", opts.Type)
	}
	return nil
}

func (v *AddVolumeOptions) createClaim() *kapi.PersistentVolumeClaim {
	return &kapi.PersistentVolumeClaim{
		ObjectMeta: kapi.ObjectMeta{
			Name: v.ClaimName,
		},
		Spec: kapi.PersistentVolumeClaimSpec{
			AccessModes: []kapi.PersistentVolumeAccessMode{kapi.PersistentVolumeAccessMode(v.ClaimMode)},
			Resources: kapi.ResourceRequirements{
				Requests: kapi.ResourceList{
					kapi.ResourceName(kapi.ResourceStorage): kresource.MustParse(v.ClaimSize),
				},
			},
		},
	}
}

func (v *VolumeOptions) setVolumeSource(kv *kapi.Volume) error {
	var err error
	opts := v.AddOpts
	if len(opts.Type) > 0 {
		err = setVolumeSourceByType(kv, opts)
	} else if len(opts.Source) > 0 {
		err = json.Unmarshal([]byte(opts.Source), &kv.VolumeSource)
	}
	return err
}

func (v *VolumeOptions) setVolumeMount(spec *kapi.PodSpec, info *resource.Info) error {
	opts := v.AddOpts
	containers, _ := selectContainers(spec.Containers, v.Containers)
	if len(containers) == 0 && v.Containers != "*" {
		fmt.Fprintf(v.Err, "warning: %s/%s does not have any containers matching %q\n", info.Mapping.Resource, info.Name, v.Containers)
		return nil
	}

	for _, c := range containers {
		for _, m := range c.VolumeMounts {
			if path.Clean(m.MountPath) == path.Clean(opts.MountPath) && m.Name != v.Name {
				return fmt.Errorf("volume mount '%s' already exists for container '%s'", opts.MountPath, c.Name)
			}
		}
		for i, m := range c.VolumeMounts {
			if m.Name == v.Name {
				c.VolumeMounts = append(c.VolumeMounts[:i], c.VolumeMounts[i+1:]...)
				break
			}
		}
		volumeMount := &kapi.VolumeMount{
			Name:      v.Name,
			MountPath: path.Clean(opts.MountPath),
		}
		c.VolumeMounts = append(c.VolumeMounts, *volumeMount)
	}
	return nil
}

func (v *VolumeOptions) getVolumeName(spec *kapi.PodSpec, singleResource bool) (string, error) {
	opts := v.AddOpts
	if opts.Overwrite {
		// Multiple resources can have same mount-path for different volumes,
		// so restrict it for single resource to uniquely find the volume
		if !singleResource {
			return "", fmt.Errorf("you must specify --name for the volume name when dealing with multiple resources")
		}
		if len(opts.MountPath) > 0 {
			containers, _ := selectContainers(spec.Containers, v.Containers)
			var name string
			matchCount := 0
			for _, c := range containers {
				for _, m := range c.VolumeMounts {
					if path.Clean(m.MountPath) == path.Clean(opts.MountPath) {
						name = m.Name
						matchCount += 1
						break
					}
				}
			}

			switch matchCount {
			case 0:
				return "", fmt.Errorf("unable to find the volume for mount-path: %s", opts.MountPath)
			case 1:
				return name, nil
			default:
				return "", fmt.Errorf("found multiple volumes with same mount-path: %s", opts.MountPath)
			}
		} else {
			return "", fmt.Errorf("ambiguous --overwrite, specify --name or --mount-path")
		}
	} else { // Generate volume name
		name := kapi.SimpleNameGenerator.GenerateName(volumePrefix)
		if len(v.Output) == 0 {
			fmt.Fprintf(v.Err, "info: Generated volume name: %s\n", name)
		}
		return name, nil
	}
}

func (v *VolumeOptions) addVolumeToSpec(spec *kapi.PodSpec, info *resource.Info, singleResource bool) error {
	opts := v.AddOpts
	if len(v.Name) == 0 {
		var err error
		v.Name, err = v.getVolumeName(spec, singleResource)
		if err != nil {
			return err
		}
	}
	newVolume := &kapi.Volume{
		Name: v.Name,
	}
	setSource := true
	for i, vol := range spec.Volumes {
		if v.Name == vol.Name {
			if !opts.Overwrite {
				return fmt.Errorf("volume '%s' already exists. Use --overwrite to replace", v.Name)
			}
			if !opts.TypeChanged && len(opts.Source) == 0 {
				newVolume.VolumeSource = vol.VolumeSource
				setSource = false
			}
			spec.Volumes = append(spec.Volumes[:i], spec.Volumes[i+1:]...)
			break
		}
	}

	if setSource {
		err := v.setVolumeSource(newVolume)
		if err != nil {
			return err
		}
	}
	spec.Volumes = append(spec.Volumes, *newVolume)

	if len(opts.MountPath) > 0 {
		err := v.setVolumeMount(spec, info)
		if err != nil {
			return err
		}
	}
	return nil
}

func (v *VolumeOptions) removeSpecificVolume(spec *kapi.PodSpec, containers, skippedContainers []*kapi.Container) error {
	for _, c := range containers {
		for i, m := range c.VolumeMounts {
			if v.Name == m.Name {
				c.VolumeMounts = append(c.VolumeMounts[:i], c.VolumeMounts[i+1:]...)
				break
			}
		}
	}

	// Remove volume if no container is using it
	found := false
	for _, c := range skippedContainers {
		for _, m := range c.VolumeMounts {
			if v.Name == m.Name {
				found = true
				break
			}
		}
		if found {
			break
		}
	}
	if !found {
		foundVolume := false
		for i, vol := range spec.Volumes {
			if v.Name == vol.Name {
				spec.Volumes = append(spec.Volumes[:i], spec.Volumes[i+1:]...)
				foundVolume = true
				break
			}
		}
		if !foundVolume {
			return fmt.Errorf("volume '%s' not found", v.Name)
		}
	}
	return nil
}

func (v *VolumeOptions) removeVolumeFromSpec(spec *kapi.PodSpec, info *resource.Info) error {
	containers, skippedContainers := selectContainers(spec.Containers, v.Containers)
	if len(containers) == 0 && v.Containers != "*" {
		fmt.Fprintf(v.Err, "warning: %s/%s does not have any containers matching %q\n", info.Mapping.Resource, info.Name, v.Containers)
		return nil
	}

	if len(v.Name) == 0 {
		for _, c := range containers {
			c.VolumeMounts = []kapi.VolumeMount{}
		}
		spec.Volumes = []kapi.Volume{}
	} else {
		err := v.removeSpecificVolume(spec, containers, skippedContainers)
		if err != nil {
			return err
		}
	}
	return nil
}

func sourceAccessMode(readOnly bool) string {
	if readOnly {
		return " read-only"
	}
	return ""
}

func describePersistentVolumeClaim(claim *kapi.PersistentVolumeClaim) string {
	if len(claim.Spec.VolumeName) == 0 {
		// TODO: check for other dimensions of request - IOPs, etc
		if val, ok := claim.Spec.Resources.Requests[kapi.ResourceStorage]; ok {
			return fmt.Sprintf("waiting for %sB allocation", val.String())
		}
		return "waiting to allocate"
	}
	// TODO: check for other dimensions of capacity?
	if val, ok := claim.Status.Capacity[kapi.ResourceStorage]; ok {
		return fmt.Sprintf("allocated %sB", val.String())
	}
	return "allocated unknown size"
}

func describeVolumeSource(source *kapi.VolumeSource) string {
	switch {
	case source.AWSElasticBlockStore != nil:
		return fmt.Sprintf("AWS EBS %s type=%s partition=%d%s", source.AWSElasticBlockStore.VolumeID, source.AWSElasticBlockStore.FSType, source.AWSElasticBlockStore.Partition, sourceAccessMode(source.AWSElasticBlockStore.ReadOnly))
	case source.EmptyDir != nil:
		return "empty directory"
	case source.GCEPersistentDisk != nil:
		return fmt.Sprintf("GCE PD %s type=%s partition=%d%s", source.GCEPersistentDisk.PDName, source.GCEPersistentDisk.FSType, source.GCEPersistentDisk.Partition, sourceAccessMode(source.GCEPersistentDisk.ReadOnly))
	case source.GitRepo != nil:
		if len(source.GitRepo.Revision) == 0 {
			return fmt.Sprintf("Git repository %s", source.GitRepo.Repository)
		}
		return fmt.Sprintf("Git repository %s @ %s", source.GitRepo.Repository, source.GitRepo.Revision)
	case source.Glusterfs != nil:
		return fmt.Sprintf("GlusterFS %s:%s%s", source.Glusterfs.EndpointsName, source.Glusterfs.Path, sourceAccessMode(source.Glusterfs.ReadOnly))
	case source.HostPath != nil:
		return fmt.Sprintf("host path %s", source.HostPath.Path)
	case source.ISCSI != nil:
		return fmt.Sprintf("ISCSI %s target-portal=%s type=%s lun=%d%s", source.ISCSI.IQN, source.ISCSI.TargetPortal, source.ISCSI.FSType, source.ISCSI.Lun, sourceAccessMode(source.ISCSI.ReadOnly))
	case source.NFS != nil:
		return fmt.Sprintf("NFS %s:%s%s", source.NFS.Server, source.NFS.Path, sourceAccessMode(source.NFS.ReadOnly))
	case source.PersistentVolumeClaim != nil:
		return fmt.Sprintf("pvc/%s%s", source.PersistentVolumeClaim.ClaimName, sourceAccessMode(source.PersistentVolumeClaim.ReadOnly))
	case source.RBD != nil:
		return fmt.Sprintf("Ceph RBD %v type=%s image=%s pool=%s%s", source.RBD.CephMonitors, source.RBD.FSType, source.RBD.RBDImage, source.RBD.RBDPool, sourceAccessMode(source.RBD.ReadOnly))
	case source.Secret != nil:
		return fmt.Sprintf("secret/%s", source.Secret.SecretName)
	default:
		return "unknown"
	}
}

func (v *VolumeOptions) listVolumeForSpec(spec *kapi.PodSpec, info *resource.Info) error {
	containers, _ := selectContainers(spec.Containers, v.Containers)
	if len(containers) == 0 && v.Containers != "*" {
		fmt.Fprintf(v.Err, "warning: %s/%s does not have any containers matching %q\n", info.Mapping.Resource, info.Name, v.Containers)
		return nil
	}

	fmt.Fprintf(v.Out, "%s/%s\n", info.Mapping.Resource, info.Name)
	checkName := (len(v.Name) > 0)
	found := false
	for _, vol := range spec.Volumes {
		if checkName && v.Name != vol.Name {
			continue
		}
		found = true

		refInfo := ""
		if vol.VolumeSource.PersistentVolumeClaim != nil {
			claimName := vol.VolumeSource.PersistentVolumeClaim.ClaimName
			claim, err := v.Client.PersistentVolumeClaims(info.Namespace).Get(claimName)
			switch {
			case err == nil:
				refInfo = fmt.Sprintf("(%s)", describePersistentVolumeClaim(claim))
			case apierrs.IsNotFound(err):
				refInfo = "(does not exist)"
			default:
				fmt.Fprintf(v.Err, "error: unable to retrieve persistent volume claim %s referenced in %s/%s: %v", claimName, info.Mapping.Resource, info.Name, err)
			}
		}
		if len(refInfo) > 0 {
			refInfo = " " + refInfo
		}

		fmt.Fprintf(v.Out, "  %s%s as %s\n", describeVolumeSource(&vol.VolumeSource), refInfo, vol.Name)
		for _, c := range containers {
			for _, m := range c.VolumeMounts {
				if vol.Name != m.Name {
					continue
				}
				if len(spec.Containers) == 1 {
					fmt.Fprintf(v.Out, "    mounted at %s\n", m.MountPath)
				} else {
					fmt.Fprintf(v.Out, "    mounted at %s in container %s\n", m.MountPath, c.Name)
				}
			}
		}
	}
	if checkName && !found {
		return fmt.Errorf("volume %q not found", v.Name)
	}

	return nil
}