kubernetes/pkg/volume/flexvolume/plugin.go

/*
Copyright 2017 The Kubernetes Authors.

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 flexvolume

import (
	"fmt"
	"path/filepath"
	"runtime"
	"strings"
	"sync"

	api "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/klog/v2"
	"k8s.io/kubernetes/pkg/volume"
	"k8s.io/kubernetes/pkg/volume/util"
	"k8s.io/mount-utils"
	"k8s.io/utils/exec"
	utilstrings "k8s.io/utils/strings"
)

const (
	flexVolumePluginName = "kubernetes.io/flexvolume"
)

// FlexVolumePlugin object.
type flexVolumePlugin struct {
	driverName string
	execPath   string
	host       volume.VolumeHost
	runner     exec.Interface

	sync.Mutex
	unsupportedCommands []string
	capabilities        DriverCapabilities
}

type flexVolumeAttachablePlugin struct {
	*flexVolumePlugin
}

var _ volume.AttachableVolumePlugin = &flexVolumeAttachablePlugin{}
var _ volume.PersistentVolumePlugin = &flexVolumePlugin{}
var _ volume.NodeExpandableVolumePlugin = &flexVolumePlugin{}
var _ volume.ExpandableVolumePlugin = &flexVolumePlugin{}

var _ volume.DeviceMountableVolumePlugin = &flexVolumeAttachablePlugin{}

// PluginFactory create flex volume plugin
type PluginFactory interface {
	NewFlexVolumePlugin(pluginDir, driverName string, runner exec.Interface) (volume.VolumePlugin, error)
}

type pluginFactory struct{}

func (pluginFactory) NewFlexVolumePlugin(pluginDir, name string, runner exec.Interface) (volume.VolumePlugin, error) {
	execPath := filepath.Join(pluginDir, name)

	driverName := utilstrings.UnescapeQualifiedName(name)

	flexPlugin := &flexVolumePlugin{
		driverName:          driverName,
		execPath:            execPath,
		runner:              runner,
		unsupportedCommands: []string{},
	}

	// Initialize the plugin and probe the capabilities
	call := flexPlugin.NewDriverCall(initCmd)
	ds, err := call.Run()
	if err != nil {
		return nil, err
	}
	flexPlugin.capabilities = *ds.Capabilities

	if flexPlugin.capabilities.Attach {
		// Plugin supports attach/detach, so return flexVolumeAttachablePlugin
		return &flexVolumeAttachablePlugin{flexVolumePlugin: flexPlugin}, nil
	}
	return flexPlugin, nil
}

// Init is part of the volume.VolumePlugin interface.
func (plugin *flexVolumePlugin) Init(host volume.VolumeHost) error {
	plugin.host = host
	// Hardwired 'success' as any errors from calling init() will be caught by NewFlexVolumePlugin()
	return nil
}

func (plugin *flexVolumePlugin) VerifyExhaustedResource(spec *volume.Spec) bool {
	return false
}

func (plugin *flexVolumePlugin) getExecutable() string {
	parts := strings.Split(plugin.driverName, "/")
	execName := parts[len(parts)-1]
	execPath := filepath.Join(plugin.execPath, execName)
	if runtime.GOOS == "windows" {
		execPath = util.GetWindowsPath(execPath)
	}
	return execPath
}

// Name is part of the volume.VolumePlugin interface.
func (plugin *flexVolumePlugin) GetPluginName() string {
	return plugin.driverName
}

// GetVolumeName is part of the volume.VolumePlugin interface.
func (plugin *flexVolumePlugin) GetVolumeName(spec *volume.Spec) (string, error) {
	call := plugin.NewDriverCall(getVolumeNameCmd)
	call.AppendSpec(spec, plugin.host, nil)

	_, err := call.Run()
	if isCmdNotSupportedErr(err) {
		return (*pluginDefaults)(plugin).GetVolumeName(spec)
	} else if err != nil {
		return "", err
	}

	name, err := (*pluginDefaults)(plugin).GetVolumeName(spec)
	if err != nil {
		return "", err
	}

	klog.V(4).Info(logPrefix(plugin), "GetVolumeName is not supported yet. Defaulting to PV or volume name: ", name)

	return name, nil
}

// CanSupport is part of the volume.VolumePlugin interface.
func (plugin *flexVolumePlugin) CanSupport(spec *volume.Spec) bool {
	sourceDriver, err := getDriver(spec)
	if err != nil {
		return false
	}
	return sourceDriver == plugin.driverName
}

// RequiresRemount is part of the volume.VolumePlugin interface.
func (plugin *flexVolumePlugin) RequiresRemount(spec *volume.Spec) bool {
	return false
}

// GetAccessModes gets the allowed access modes for this plugin.
func (plugin *flexVolumePlugin) GetAccessModes() []api.PersistentVolumeAccessMode {
	return []api.PersistentVolumeAccessMode{
		api.ReadWriteOnce,
		api.ReadOnlyMany,
	}
}

// NewMounter is part of the volume.VolumePlugin interface.
func (plugin *flexVolumePlugin) NewMounter(spec *volume.Spec, pod *api.Pod) (volume.Mounter, error) {
	return plugin.newMounterInternal(spec, pod, plugin.host.GetMounter(), plugin.runner)
}

// newMounterInternal is the internal mounter routine to build the volume.
func (plugin *flexVolumePlugin) newMounterInternal(spec *volume.Spec, pod *api.Pod, mounter mount.Interface, runner exec.Interface) (volume.Mounter, error) {
	sourceDriver, err := getDriver(spec)
	if err != nil {
		return nil, err
	}

	readOnly, err := getReadOnly(spec)
	if err != nil {
		return nil, err
	}

	var metricsProvider volume.MetricsProvider
	if plugin.capabilities.SupportsMetrics {
		metricsProvider = volume.NewMetricsStatFS(plugin.host.GetPodVolumeDir(
			pod.UID, utilstrings.EscapeQualifiedName(sourceDriver), spec.Name()))
	} else {
		metricsProvider = &volume.MetricsNil{}
	}

	return &flexVolumeMounter{
		flexVolume: &flexVolume{
			driverName:            sourceDriver,
			execPath:              plugin.getExecutable(),
			mounter:               mounter,
			plugin:                plugin,
			podName:               pod.Name,
			podUID:                pod.UID,
			podNamespace:          pod.Namespace,
			podServiceAccountName: pod.Spec.ServiceAccountName,
			volName:               spec.Name(),
			MetricsProvider:       metricsProvider,
		},
		runner:   runner,
		spec:     spec,
		readOnly: readOnly,
	}, nil
}

// NewUnmounter is part of the volume.VolumePlugin interface.
func (plugin *flexVolumePlugin) NewUnmounter(volName string, podUID types.UID) (volume.Unmounter, error) {
	return plugin.newUnmounterInternal(volName, podUID, plugin.host.GetMounter(), plugin.runner)
}

// newUnmounterInternal is the internal unmounter routine to clean the volume.
func (plugin *flexVolumePlugin) newUnmounterInternal(volName string, podUID types.UID, mounter mount.Interface, runner exec.Interface) (volume.Unmounter, error) {
	var metricsProvider volume.MetricsProvider
	if plugin.capabilities.SupportsMetrics {
		metricsProvider = volume.NewMetricsStatFS(plugin.host.GetPodVolumeDir(
			podUID, utilstrings.EscapeQualifiedName(plugin.driverName), volName))
	} else {
		metricsProvider = &volume.MetricsNil{}
	}

	return &flexVolumeUnmounter{
		flexVolume: &flexVolume{
			driverName:      plugin.driverName,
			execPath:        plugin.getExecutable(),
			mounter:         mounter,
			plugin:          plugin,
			podUID:          podUID,
			volName:         volName,
			MetricsProvider: metricsProvider,
		},
		runner: runner,
	}, nil
}

// NewAttacher is part of the volume.AttachableVolumePlugin interface.
func (plugin *flexVolumeAttachablePlugin) NewAttacher() (volume.Attacher, error) {
	return &flexVolumeAttacher{plugin}, nil
}

func (plugin *flexVolumeAttachablePlugin) NewDeviceMounter() (volume.DeviceMounter, error) {
	return plugin.NewAttacher()
}

// NewDetacher is part of the volume.AttachableVolumePlugin interface.
func (plugin *flexVolumeAttachablePlugin) NewDetacher() (volume.Detacher, error) {
	return &flexVolumeDetacher{plugin}, nil
}

func (plugin *flexVolumeAttachablePlugin) NewDeviceUnmounter() (volume.DeviceUnmounter, error) {
	return plugin.NewDetacher()
}

func (plugin *flexVolumeAttachablePlugin) CanAttach(spec *volume.Spec) (bool, error) {
	return true, nil
}

func (plugin *flexVolumeAttachablePlugin) CanDeviceMount(spec *volume.Spec) (bool, error) {
	return true, nil
}

// ConstructVolumeSpec is part of the volume.AttachableVolumePlugin interface.
func (plugin *flexVolumePlugin) ConstructVolumeSpec(volumeName, mountPath string) (volume.ReconstructedVolume, error) {
	flexVolume := &api.Volume{
		Name: volumeName,
		VolumeSource: api.VolumeSource{
			FlexVolume: &api.FlexVolumeSource{
				Driver: plugin.driverName,
			},
		},
	}
	return volume.ReconstructedVolume{
		Spec: volume.NewSpecFromVolume(flexVolume),
	}, nil
}

func (plugin *flexVolumePlugin) SupportsMountOption() bool {
	return false
}

// Mark the given commands as unsupported.
func (plugin *flexVolumePlugin) unsupported(commands ...string) {
	plugin.Lock()
	defer plugin.Unlock()
	plugin.unsupportedCommands = append(plugin.unsupportedCommands, commands...)
}

func (plugin *flexVolumePlugin) SupportsSELinuxContextMount(spec *volume.Spec) (bool, error) {
	return false, nil
}

// Returns true iff the given command is known to be unsupported.
func (plugin *flexVolumePlugin) isUnsupported(command string) bool {
	plugin.Lock()
	defer plugin.Unlock()
	for _, unsupportedCommand := range plugin.unsupportedCommands {
		if command == unsupportedCommand {
			return true
		}
	}
	return false
}

func (plugin *flexVolumePlugin) GetDeviceMountRefs(deviceMountPath string) ([]string, error) {
	mounter := plugin.host.GetMounter()
	return mounter.GetMountRefs(deviceMountPath)
}

func (plugin *flexVolumePlugin) getDeviceMountPath(spec *volume.Spec) (string, error) {
	volumeName, err := plugin.GetVolumeName(spec)
	if err != nil {
		return "", fmt.Errorf("GetVolumeName failed from getDeviceMountPath: %s", err)
	}

	mountsDir := filepath.Join(plugin.host.GetPluginDir(flexVolumePluginName), plugin.driverName, "mounts")
	return filepath.Join(mountsDir, volumeName), nil
}

func (plugin *flexVolumePlugin) RequiresFSResize() bool {
	return plugin.capabilities.RequiresFSResize
}