moby/migrate/v1/migratev1.go
Derek McGowan 3a1279393f
Use distribution reference
Remove forked reference package. Use normalized named values
everywhere and familiar functions to convert back to familiar
strings for UX and storage compatibility.

Enforce that the source repository in the distribution metadata
is always a normalized string, ignore invalid values which are not.
Update distribution tests to use normalized values.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
2017-02-07 11:08:37 -08:00

506 lines
13 KiB
Go

package v1
import (
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"runtime"
"strconv"
"sync"
"time"
"encoding/json"
"github.com/Sirupsen/logrus"
"github.com/docker/distribution/reference"
"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/pkg/ioutils"
refstore "github.com/docker/docker/reference"
"github.com/opencontainers/go-digest"
)
type graphIDRegistrar interface {
RegisterByGraphID(string, layer.ChainID, layer.DiffID, string, int64) (layer.Layer, error)
Release(layer.Layer) ([]layer.Metadata, error)
}
type graphIDMounter interface {
CreateRWLayerByGraphID(string, string, layer.ChainID) error
}
type checksumCalculator interface {
ChecksumForGraphID(id, parent, oldTarDataPath, newTarDataPath string) (diffID layer.DiffID, size int64, err error)
}
const (
graphDirName = "graph"
tarDataFileName = "tar-data.json.gz"
migrationFileName = ".migration-v1-images.json"
migrationTagsFileName = ".migration-v1-tags"
migrationDiffIDFileName = ".migration-diffid"
migrationSizeFileName = ".migration-size"
migrationTarDataFileName = ".migration-tardata"
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 refstore.Store, ms metadata.Store) error {
graphDir := filepath.Join(root, graphDirName)
if _, err := os.Lstat(graphDir); os.IsNotExist(err) {
return nil
}
mappings, err := restoreMappings(root)
if err != nil {
return err
}
if cc, ok := ls.(checksumCalculator); ok {
CalculateLayerChecksums(root, cc, mappings)
}
if registrar, ok := ls.(graphIDRegistrar); !ok {
return errUnsupported
} else if err := migrateImages(root, registrar, is, ms, mappings); err != nil {
return err
}
err = saveMappings(root, mappings)
if 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
}
// CalculateLayerChecksums walks an old graph directory and calculates checksums
// for each layer. These checksums are later used for migration.
func CalculateLayerChecksums(root string, ls checksumCalculator, mappings map[string]image.ID) {
graphDir := filepath.Join(root, graphDirName)
// spawn some extra workers also for maximum performance because the process is bounded by both cpu and io
workers := runtime.NumCPU() * 3
workQueue := make(chan string, workers)
wg := sync.WaitGroup{}
for i := 0; i < workers; i++ {
wg.Add(1)
go func() {
for id := range workQueue {
start := time.Now()
if err := calculateLayerChecksum(graphDir, id, ls); err != nil {
logrus.Errorf("could not calculate checksum for %q, %q", id, err)
}
elapsed := time.Since(start)
logrus.Debugf("layer %s took %.2f seconds", id, elapsed.Seconds())
}
wg.Done()
}()
}
dir, err := ioutil.ReadDir(graphDir)
if err != nil {
logrus.Errorf("could not read directory %q", graphDir)
return
}
for _, v := range dir {
v1ID := v.Name()
if err := imagev1.ValidateID(v1ID); err != nil {
continue
}
if _, ok := mappings[v1ID]; ok { // support old migrations without helper files
continue
}
workQueue <- v1ID
}
close(workQueue)
wg.Wait()
}
func calculateLayerChecksum(graphDir, id string, ls checksumCalculator) error {
diffIDFile := filepath.Join(graphDir, id, migrationDiffIDFileName)
if _, err := os.Lstat(diffIDFile); err == nil {
return nil
} else if !os.IsNotExist(err) {
return err
}
parent, err := getParent(filepath.Join(graphDir, id))
if err != nil {
return err
}
diffID, size, err := ls.ChecksumForGraphID(id, parent, filepath.Join(graphDir, id, tarDataFileName), filepath.Join(graphDir, id, migrationTarDataFileName))
if err != nil {
return err
}
if err := ioutil.WriteFile(filepath.Join(graphDir, id, migrationSizeFileName), []byte(strconv.Itoa(int(size))), 0600); err != nil {
return err
}
if err := ioutils.AtomicWriteFile(filepath.Join(graphDir, id, migrationDiffIDFileName), []byte(diffID), 0600); err != nil {
return err
}
logrus.Infof("calculated checksum for layer %s: %s", id, diffID)
return nil
}
func restoreMappings(root string) (map[string]image.ID, error) {
mappings := make(map[string]image.ID)
mfile := filepath.Join(root, migrationFileName)
f, err := os.Open(mfile)
if err != nil && !os.IsNotExist(err) {
return nil, err
} else if err == nil {
err := json.NewDecoder(f).Decode(&mappings)
if err != nil {
f.Close()
return nil, err
}
f.Close()
}
return mappings, nil
}
func saveMappings(root string, mappings map[string]image.ID) error {
mfile := filepath.Join(root, migrationFileName)
f, err := os.OpenFile(mfile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
return err
}
defer f.Close()
return json.NewEncoder(f).Encode(mappings)
}
func migrateImages(root string, ls graphIDRegistrar, is image.Store, ms metadata.Store, mappings map[string]image.ID) error {
graphDir := filepath.Join(root, graphDirName)
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
}
}
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 {
logrus.Errorf("migrate container error: %v", err)
continue
}
var c map[string]*json.RawMessage
if err := json.Unmarshal(containerJSON, &c); err != nil {
logrus.Errorf("migrate container error: %v", err)
continue
}
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 {
logrus.Errorf("migrate container error: %v", err)
continue
}
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 {
logrus.Errorf("migrate container error: %v", err)
continue
}
logrus.Infof("migrated container %s to point to %s", id, imageID)
}
return nil
}
type refAdder interface {
AddTag(ref reference.Named, id digest.Digest, force bool) error
AddDigest(ref reference.Canonical, id digest.Digest, 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.ParseNormalizedNamed(name)
if err != nil {
logrus.Errorf("migrate tags: invalid name %q, %q", name, err)
continue
}
if !reference.IsNameOnly(ref) {
logrus.Errorf("migrate tags: invalid name %q, unexpected tag or digest", name)
continue
}
if dgst, err := digest.Parse(tag); err == nil {
canonical, err := reference.WithDigest(reference.TrimNamed(ref), dgst)
if err != nil {
logrus.Errorf("migrate tags: invalid digest %q, %q", dgst, err)
continue
}
if err := rs.AddDigest(canonical, strongID.Digest(), false); err != nil {
logrus.Errorf("can't migrate digest %q for %q, err: %q", reference.FamiliarString(ref), 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.Digest(), false); err != nil {
logrus.Errorf("can't migrate tag %q for %q, err: %q", reference.FamiliarString(ref), 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 getParent(confDir string) (string, error) {
jsonFile := filepath.Join(confDir, "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(confDir, "parent"))
if err == nil && len(parentCompatibilityID) > 0 {
parent.Parent = string(parentCompatibilityID)
}
return parent.Parent, 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)
}
}()
parent, err := getParent(filepath.Join(root, graphDirName, id))
if err != nil {
return err
}
var parentID image.ID
if parent != "" {
var exists bool
if parentID, exists = mappings[parent]; !exists {
if err := migrateImage(parent, root, ls, is, ms, mappings); err != nil {
// todo: fail or allow broken chains?
return err
}
parentID = mappings[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
}
diffIDData, err := ioutil.ReadFile(filepath.Join(root, graphDirName, id, migrationDiffIDFileName))
if err != nil {
return err
}
diffID, err := digest.Parse(string(diffIDData))
if err != nil {
return err
}
sizeStr, err := ioutil.ReadFile(filepath.Join(root, graphDirName, id, migrationSizeFileName))
if err != nil {
return err
}
size, err := strconv.ParseInt(string(sizeStr), 10, 64)
if err != nil {
return err
}
layer, err := ls.RegisterByGraphID(id, rootFS.ChainID(), layer.DiffID(diffID), filepath.Join(root, graphDirName, id, migrationTarDataFileName), size)
if err != nil {
return err
}
logrus.Infof("migrated layer %s to %s", id, layer.DiffID())
jsonFile := filepath.Join(root, graphDirName, id, "json")
imageJSON, err := ioutil.ReadFile(jsonFile)
if err != nil {
return err
}
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.Parse(string(checksum))
if err == nil {
V2MetadataService := metadata.NewV2MetadataService(ms)
V2MetadataService.Add(layer.DiffID(), metadata.V2Metadata{Digest: 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)
}