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moby--moby/migrate/v1/migratev1.go

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package v1
import (
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"encoding/json"
"github.com/Sirupsen/logrus"
"github.com/docker/distribution/digest"
"github.com/docker/docker/distribution/metadata"
"github.com/docker/docker/image"
imagev1 "github.com/docker/docker/image/v1"
"github.com/docker/docker/layer"
"github.com/docker/docker/reference"
)
type graphIDRegistrar interface {
RegisterByGraphID(string, layer.ChainID, string) (layer.Layer, error)
Release(layer.Layer) ([]layer.Metadata, error)
}
type graphIDMounter interface {
CreateRWLayerByGraphID(string, string, layer.ChainID) error
}
const (
graphDirName = "graph"
tarDataFileName = "tar-data.json.gz"
migrationFileName = ".migration-v1-images.json"
migrationTagsFileName = ".migration-v1-tags"
containersDirName = "containers"
configFileNameLegacy = "config.json"
configFileName = "config.v2.json"
repositoriesFilePrefixLegacy = "repositories-"
)
var (
errUnsupported = errors.New("migration is not supported")
)
// Migrate takes an old graph directory and transforms the metadata into the
// new format.
func Migrate(root, driverName string, ls layer.Store, is image.Store, rs reference.Store, ms metadata.Store) error {
mappings := make(map[string]image.ID)
if registrar, ok := ls.(graphIDRegistrar); !ok {
return errUnsupported
} else if err := migrateImages(root, registrar, is, ms, mappings); err != nil {
return err
}
if mounter, ok := ls.(graphIDMounter); !ok {
return errUnsupported
} else if err := migrateContainers(root, mounter, is, mappings); err != nil {
return err
}
if err := migrateRefs(root, driverName, rs, mappings); err != nil {
return err
}
return nil
}
func migrateImages(root string, ls graphIDRegistrar, is image.Store, ms metadata.Store, mappings map[string]image.ID) error {
graphDir := filepath.Join(root, graphDirName)
if _, err := os.Lstat(graphDir); err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
mfile := filepath.Join(root, migrationFileName)
f, err := os.Open(mfile)
if err != nil && !os.IsNotExist(err) {
return err
} else if err == nil {
err := json.NewDecoder(f).Decode(&mappings)
if err != nil {
f.Close()
return err
}
f.Close()
}
dir, err := ioutil.ReadDir(graphDir)
if err != nil {
return err
}
for _, v := range dir {
v1ID := v.Name()
if err := imagev1.ValidateID(v1ID); err != nil {
continue
}
if _, exists := mappings[v1ID]; exists {
continue
}
if err := migrateImage(v1ID, root, ls, is, ms, mappings); err != nil {
continue
}
}
f, err = os.OpenFile(mfile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
return err
}
defer f.Close()
if err := json.NewEncoder(f).Encode(mappings); err != nil {
return err
}
return nil
}
func migrateContainers(root string, ls graphIDMounter, is image.Store, imageMappings map[string]image.ID) error {
containersDir := filepath.Join(root, containersDirName)
dir, err := ioutil.ReadDir(containersDir)
if err != nil {
return err
}
for _, v := range dir {
id := v.Name()
if _, err := os.Stat(filepath.Join(containersDir, id, configFileName)); err == nil {
continue
}
containerJSON, err := ioutil.ReadFile(filepath.Join(containersDir, id, configFileNameLegacy))
if err != nil {
return err
}
var c map[string]*json.RawMessage
if err := json.Unmarshal(containerJSON, &c); err != nil {
return err
}
imageStrJSON, ok := c["Image"]
if !ok {
return fmt.Errorf("invalid container configuration for %v", id)
}
var image string
if err := json.Unmarshal([]byte(*imageStrJSON), &image); err != nil {
return err
}
imageID, ok := imageMappings[image]
if !ok {
logrus.Errorf("image not migrated %v", imageID) // non-fatal error
continue
}
c["Image"] = rawJSON(imageID)
containerJSON, err = json.Marshal(c)
if err != nil {
return err
}
if err := ioutil.WriteFile(filepath.Join(containersDir, id, configFileName), containerJSON, 0600); err != nil {
return err
}
img, err := is.Get(imageID)
if err != nil {
return err
}
if err := ls.CreateRWLayerByGraphID(id, id, img.RootFS.ChainID()); err != nil {
return err
}
logrus.Infof("migrated container %s to point to %s", id, imageID)
}
return nil
}
type refAdder interface {
AddTag(ref reference.Named, id image.ID, force bool) error
AddDigest(ref reference.Canonical, id image.ID, force bool) error
}
func migrateRefs(root, driverName string, rs refAdder, mappings map[string]image.ID) error {
migrationFile := filepath.Join(root, migrationTagsFileName)
if _, err := os.Lstat(migrationFile); !os.IsNotExist(err) {
return err
}
type repositories struct {
Repositories map[string]map[string]string
}
var repos repositories
f, err := os.Open(filepath.Join(root, repositoriesFilePrefixLegacy+driverName))
if err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
defer f.Close()
if err := json.NewDecoder(f).Decode(&repos); err != nil {
return err
}
for name, repo := range repos.Repositories {
for tag, id := range repo {
if strongID, exists := mappings[id]; exists {
ref, err := reference.WithName(name)
if err != nil {
logrus.Errorf("migrate tags: invalid name %q, %q", name, err)
continue
}
if dgst, err := digest.ParseDigest(tag); err == nil {
canonical, err := reference.WithDigest(ref, dgst)
if err != nil {
logrus.Errorf("migrate tags: invalid digest %q, %q", dgst, err)
continue
}
if err := rs.AddDigest(canonical, strongID, false); err != nil {
logrus.Errorf("can't migrate digest %q for %q, err: %q", ref.String(), strongID, err)
}
} else {
tagRef, err := reference.WithTag(ref, tag)
if err != nil {
logrus.Errorf("migrate tags: invalid tag %q, %q", tag, err)
continue
}
if err := rs.AddTag(tagRef, strongID, false); err != nil {
logrus.Errorf("can't migrate tag %q for %q, err: %q", ref.String(), strongID, err)
}
}
logrus.Infof("migrated tag %s:%s to point to %s", name, tag, strongID)
}
}
}
mf, err := os.Create(migrationFile)
if err != nil {
return err
}
mf.Close()
return nil
}
func migrateImage(id, root string, ls graphIDRegistrar, is image.Store, ms metadata.Store, mappings map[string]image.ID) (err error) {
defer func() {
if err != nil {
logrus.Errorf("migration failed for %v, err: %v", id, err)
}
}()
jsonFile := filepath.Join(root, graphDirName, id, "json")
imageJSON, err := ioutil.ReadFile(jsonFile)
if err != nil {
return err
}
var parent struct {
Parent string
ParentID digest.Digest `json:"parent_id"`
}
if err := json.Unmarshal(imageJSON, &parent); err != nil {
return err
}
if parent.Parent == "" && parent.ParentID != "" { // v1.9
parent.Parent = parent.ParentID.Hex()
}
// compatibilityID for parent
parentCompatibilityID, err := ioutil.ReadFile(filepath.Join(root, graphDirName, id, "parent"))
if err == nil && len(parentCompatibilityID) > 0 {
parent.Parent = string(parentCompatibilityID)
}
var parentID image.ID
if parent.Parent != "" {
var exists bool
if parentID, exists = mappings[parent.Parent]; !exists {
if err := migrateImage(parent.Parent, root, ls, is, ms, mappings); err != nil {
// todo: fail or allow broken chains?
return err
}
parentID = mappings[parent.Parent]
}
}
rootFS := image.NewRootFS()
var history []image.History
if parentID != "" {
parentImg, err := is.Get(parentID)
if err != nil {
return err
}
rootFS = parentImg.RootFS
history = parentImg.History
}
layer, err := ls.RegisterByGraphID(id, rootFS.ChainID(), filepath.Join(filepath.Join(root, graphDirName, id, tarDataFileName)))
if err != nil {
return err
}
logrus.Infof("migrated layer %s to %s", id, layer.DiffID())
h, err := imagev1.HistoryFromConfig(imageJSON, false)
if err != nil {
return err
}
history = append(history, h)
rootFS.Append(layer.DiffID())
config, err := imagev1.MakeConfigFromV1Config(imageJSON, rootFS, history)
if err != nil {
return err
}
strongID, err := is.Create(config)
if err != nil {
return err
}
logrus.Infof("migrated image %s to %s", id, strongID)
if parentID != "" {
if err := is.SetParent(strongID, parentID); err != nil {
return err
}
}
checksum, err := ioutil.ReadFile(filepath.Join(root, graphDirName, id, "checksum"))
if err == nil { // best effort
dgst, err := digest.ParseDigest(string(checksum))
if err == nil {
blobSumService := metadata.NewBlobSumService(ms)
blobSumService.Add(layer.DiffID(), dgst)
}
}
_, err = ls.Release(layer)
if err != nil {
return err
}
mappings[id] = strongID
return
}
func rawJSON(value interface{}) *json.RawMessage {
jsonval, err := json.Marshal(value)
if err != nil {
return nil
}
return (*json.RawMessage)(&jsonval)
}