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image_cloner.go
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image_cloner.go
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package image_cloner // import "code.cloudfoundry.org/grootfs/store/image_cloner"
import (
"crypto/sha256"
"encoding/hex"
"errors"
"io/ioutil"
"os"
"path"
"path/filepath"
"code.cloudfoundry.org/grootfs/groot"
"code.cloudfoundry.org/grootfs/store"
"code.cloudfoundry.org/lager"
specsv1 "github.com/opencontainers/image-spec/specs-go/v1"
errorspkg "github.com/pkg/errors"
)
type ImageDriverSpec struct {
BaseVolumeIDs []string
Mount bool
ImagePath string
DiskLimit int64
ExclusiveDiskLimit bool
}
//go:generate counterfeiter . ImageDriver
type ImageDriver interface {
CreateImage(logger lager.Logger, spec ImageDriverSpec) (groot.MountInfo, error)
DestroyImage(logger lager.Logger, path string) error
FetchStats(logger lager.Logger, path string) (groot.VolumeStats, error)
}
type ImageCloner struct {
imageDriver ImageDriver
storePath string
}
func NewImageCloner(imageDriver ImageDriver, storePath string) *ImageCloner {
return &ImageCloner{
imageDriver: imageDriver,
storePath: storePath,
}
}
func (b *ImageCloner) ImageIDs(logger lager.Logger) ([]string, error) {
images := []string{}
existingImages, err := ioutil.ReadDir(path.Join(b.storePath, store.ImageDirName))
if err != nil {
return nil, errorspkg.Wrap(err, "failed to read images dir")
}
for _, imageInfo := range existingImages {
images = append(images, imageInfo.Name())
}
return images, nil
}
func (b *ImageCloner) Create(logger lager.Logger, spec groot.ImageSpec) (groot.ImageInfo, error) {
logger = logger.Session("making-image", lager.Data{"storePath": b.storePath, "id": spec.ID})
logger.Info("starting")
defer logger.Info("ending")
imagePath := b.imagePath(spec.ID)
imageRootFSPath := filepath.Join(imagePath, "rootfs")
var err error
defer func() {
if err != nil {
log := logger.Session("create-failed-cleaning-up", lager.Data{
"id": spec.ID,
"cause": err.Error(),
})
log.Info("starting")
defer log.Info("ending")
if err = b.imageDriver.DestroyImage(logger, imagePath); err != nil {
log.Error("destroying-rootfs-image", err)
}
if err := os.RemoveAll(imagePath); err != nil {
log.Error("deleting-image-path", err)
}
}
}()
if err = os.Mkdir(imagePath, 0700); err != nil {
return groot.ImageInfo{}, errorspkg.Wrap(err, "making image path")
}
imageDriverSpec := ImageDriverSpec{
BaseVolumeIDs: spec.BaseVolumeIDs,
Mount: spec.Mount,
ImagePath: imagePath,
DiskLimit: spec.DiskLimit,
ExclusiveDiskLimit: spec.ExcludeBaseImageFromQuota,
}
var mountInfo groot.MountInfo
if mountInfo, err = b.imageDriver.CreateImage(logger, imageDriverSpec); err != nil {
logger.Error("creating-image-failed", err, lager.Data{"imageDriverSpec": imageDriverSpec})
return groot.ImageInfo{}, errorspkg.Wrap(err, "creating image")
}
if err := b.setOwnership(spec,
imagePath,
imageRootFSPath,
); err != nil {
logger.Error("setting-permission-failed", err, lager.Data{"imageDriverSpec": imageDriverSpec})
return groot.ImageInfo{}, err
}
imageInfo, err := b.imageInfo(imageRootFSPath, imagePath, spec.BaseImage, mountInfo, spec.Mount)
if err != nil {
logger.Error("creating-image-object", err)
return groot.ImageInfo{}, errorspkg.Wrap(err, "creating image object")
}
if err := b.createVolumesSources(imageInfo.Mounts, spec.OwnerUID, spec.OwnerGID); err != nil {
return groot.ImageInfo{}, errorspkg.Wrap(err, "creating volume source")
}
return imageInfo, nil
}
func (b *ImageCloner) createVolumesSources(mounts []groot.MountInfo, ownerUID, ownerGID int) error {
for _, mountInfo := range mounts {
if mountInfo.Type != "bind" {
continue
}
if err := os.Mkdir(mountInfo.Source, 0755); err != nil {
return err
}
if err := os.Chown(mountInfo.Source, ownerUID, ownerGID); err != nil {
return err
}
}
return nil
}
func (b *ImageCloner) Destroy(logger lager.Logger, id string) error {
logger = logger.Session("deleting-image", lager.Data{"storePath": b.storePath, "id": id})
logger.Info("starting")
defer logger.Info("ending")
if ok, err := b.Exists(id); !ok {
logger.Error("checking-image-path-failed", err)
if err != nil {
return errorspkg.Wrapf(err, "unable to check image: %s", id)
}
return errorspkg.Errorf("image not found: %s", id)
}
imagePath := b.imagePath(id)
var volDriverErr error
if volDriverErr = b.imageDriver.DestroyImage(logger, imagePath); volDriverErr != nil {
logger.Error("destroying-image-failed", volDriverErr)
}
if _, err := os.Stat(imagePath); err == nil {
logger.Error("deleting-image-dir-failed", err, lager.Data{"volumeDriverError": volDriverErr})
return errors.New("deleting image path")
}
return nil
}
func (b *ImageCloner) Exists(id string) (bool, error) {
imagePath := path.Join(b.storePath, store.ImageDirName, id)
if _, err := os.Stat(imagePath); err != nil {
if os.IsNotExist(err) {
return false, nil
}
return false, errorspkg.Wrapf(err, "checking if image `%s` exists", id)
}
return true, nil
}
func (b *ImageCloner) Stats(logger lager.Logger, id string) (groot.VolumeStats, error) {
logger = logger.Session("fetching-stats", lager.Data{"id": id})
logger.Debug("starting")
defer logger.Debug("ending")
if ok, err := b.Exists(id); !ok {
logger.Error("checking-image-path-failed", err)
return groot.VolumeStats{}, errorspkg.Errorf("image not found: %s", id)
}
imagePath := b.imagePath(id)
return b.imageDriver.FetchStats(logger, imagePath)
}
var OpenFile = os.OpenFile
func (b *ImageCloner) imageInfo(rootfsPath, imagePath string, baseImage specsv1.Image, mountJson groot.MountInfo, mount bool) (groot.ImageInfo, error) {
imageInfo := groot.ImageInfo{
Path: imagePath,
Rootfs: rootfsPath,
Image: baseImage,
}
if !mount {
imageInfo.Mounts = []groot.MountInfo{mountJson}
}
for volume, _ := range baseImage.Config.Volumes {
volumeHash := sha256.Sum256([]byte(volume))
mountSourceName := "vol-" + hex.EncodeToString(volumeHash[:32])
imageInfo.Mounts = append(imageInfo.Mounts, groot.MountInfo{
Destination: volume,
Source: filepath.Join(imagePath, mountSourceName),
Type: "bind",
Options: []string{"bind"},
})
}
return imageInfo, nil
}
func (b *ImageCloner) imagePath(id string) string {
return path.Join(b.storePath, store.ImageDirName, id)
}
func (b *ImageCloner) setOwnership(spec groot.ImageSpec, paths ...string) error {
if spec.OwnerUID == 0 && spec.OwnerGID == 0 {
return nil
}
for _, path := range paths {
if err := os.Chown(path, spec.OwnerUID, spec.OwnerGID); err != nil {
return errorspkg.Wrapf(err, "changing %s ownership to %d:%d", path, spec.OwnerUID, spec.OwnerGID)
}
}
return nil
}