mirror of https://github.com/docker/docs.git
505 lines
13 KiB
Go
505 lines
13 KiB
Go
package v1
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import (
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"errors"
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"runtime"
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"strconv"
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"sync"
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"time"
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"encoding/json"
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"github.com/Sirupsen/logrus"
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"github.com/docker/distribution/digest"
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"github.com/docker/docker/distribution/metadata"
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"github.com/docker/docker/image"
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imagev1 "github.com/docker/docker/image/v1"
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"github.com/docker/docker/layer"
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"github.com/docker/docker/pkg/ioutils"
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"github.com/docker/docker/reference"
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)
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type graphIDRegistrar interface {
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RegisterByGraphID(string, layer.ChainID, layer.DiffID, string, int64) (layer.Layer, error)
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Release(layer.Layer) ([]layer.Metadata, error)
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}
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type graphIDMounter interface {
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CreateRWLayerByGraphID(string, string, layer.ChainID) error
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}
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type checksumCalculator interface {
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ChecksumForGraphID(id, parent, oldTarDataPath, newTarDataPath string) (diffID layer.DiffID, size int64, err error)
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}
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const (
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graphDirName = "graph"
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tarDataFileName = "tar-data.json.gz"
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migrationFileName = ".migration-v1-images.json"
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migrationTagsFileName = ".migration-v1-tags"
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migrationDiffIDFileName = ".migration-diffid"
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migrationSizeFileName = ".migration-size"
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migrationTarDataFileName = ".migration-tardata"
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containersDirName = "containers"
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configFileNameLegacy = "config.json"
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configFileName = "config.v2.json"
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repositoriesFilePrefixLegacy = "repositories-"
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)
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var (
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errUnsupported = errors.New("migration is not supported")
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)
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// Migrate takes an old graph directory and transforms the metadata into the
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// new format.
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func Migrate(root, driverName string, ls layer.Store, is image.Store, rs reference.Store, ms metadata.Store) error {
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graphDir := filepath.Join(root, graphDirName)
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if _, err := os.Lstat(graphDir); os.IsNotExist(err) {
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return nil
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}
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mappings, err := restoreMappings(root)
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if err != nil {
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return err
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}
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if cc, ok := ls.(checksumCalculator); ok {
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CalculateLayerChecksums(root, cc, mappings)
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}
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if registrar, ok := ls.(graphIDRegistrar); !ok {
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return errUnsupported
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} else if err := migrateImages(root, registrar, is, ms, mappings); err != nil {
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return err
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}
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err = saveMappings(root, mappings)
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if err != nil {
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return err
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}
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if mounter, ok := ls.(graphIDMounter); !ok {
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return errUnsupported
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} else if err := migrateContainers(root, mounter, is, mappings); err != nil {
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return err
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}
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if err := migrateRefs(root, driverName, rs, mappings); err != nil {
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return err
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}
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return nil
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}
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// CalculateLayerChecksums walks an old graph directory and calculates checksums
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// for each layer. These checksums are later used for migration.
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func CalculateLayerChecksums(root string, ls checksumCalculator, mappings map[string]image.ID) {
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graphDir := filepath.Join(root, graphDirName)
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// spawn some extra workers also for maximum performance because the process is bounded by both cpu and io
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workers := runtime.NumCPU() * 3
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workQueue := make(chan string, workers)
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wg := sync.WaitGroup{}
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for i := 0; i < workers; i++ {
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wg.Add(1)
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go func() {
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for id := range workQueue {
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start := time.Now()
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if err := calculateLayerChecksum(graphDir, id, ls); err != nil {
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logrus.Errorf("could not calculate checksum for %q, %q", id, err)
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}
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elapsed := time.Since(start)
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logrus.Debugf("layer %s took %.2f seconds", id, elapsed.Seconds())
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}
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wg.Done()
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}()
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}
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dir, err := ioutil.ReadDir(graphDir)
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if err != nil {
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logrus.Errorf("could not read directory %q", graphDir)
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return
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}
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for _, v := range dir {
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v1ID := v.Name()
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if err := imagev1.ValidateID(v1ID); err != nil {
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continue
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}
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if _, ok := mappings[v1ID]; ok { // support old migrations without helper files
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continue
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}
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workQueue <- v1ID
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}
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close(workQueue)
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wg.Wait()
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}
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func calculateLayerChecksum(graphDir, id string, ls checksumCalculator) error {
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diffIDFile := filepath.Join(graphDir, id, migrationDiffIDFileName)
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if _, err := os.Lstat(diffIDFile); err == nil {
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return nil
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} else if !os.IsNotExist(err) {
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return err
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}
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parent, err := getParent(filepath.Join(graphDir, id))
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if err != nil {
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return err
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}
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diffID, size, err := ls.ChecksumForGraphID(id, parent, filepath.Join(graphDir, id, tarDataFileName), filepath.Join(graphDir, id, migrationTarDataFileName))
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if err != nil {
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return err
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}
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if err := ioutil.WriteFile(filepath.Join(graphDir, id, migrationSizeFileName), []byte(strconv.Itoa(int(size))), 0600); err != nil {
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return err
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}
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if err := ioutils.AtomicWriteFile(filepath.Join(graphDir, id, migrationDiffIDFileName), []byte(diffID), 0600); err != nil {
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return err
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}
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logrus.Infof("calculated checksum for layer %s: %s", id, diffID)
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return nil
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}
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func restoreMappings(root string) (map[string]image.ID, error) {
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mappings := make(map[string]image.ID)
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mfile := filepath.Join(root, migrationFileName)
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f, err := os.Open(mfile)
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if err != nil && !os.IsNotExist(err) {
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return nil, err
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} else if err == nil {
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err := json.NewDecoder(f).Decode(&mappings)
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if err != nil {
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f.Close()
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return nil, err
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}
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f.Close()
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}
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return mappings, nil
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}
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func saveMappings(root string, mappings map[string]image.ID) error {
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mfile := filepath.Join(root, migrationFileName)
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f, err := os.OpenFile(mfile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
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if err != nil {
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return err
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}
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defer f.Close()
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if err := json.NewEncoder(f).Encode(mappings); err != nil {
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return err
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}
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return nil
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}
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func migrateImages(root string, ls graphIDRegistrar, is image.Store, ms metadata.Store, mappings map[string]image.ID) error {
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graphDir := filepath.Join(root, graphDirName)
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dir, err := ioutil.ReadDir(graphDir)
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if err != nil {
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return err
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}
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for _, v := range dir {
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v1ID := v.Name()
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if err := imagev1.ValidateID(v1ID); err != nil {
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continue
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}
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if _, exists := mappings[v1ID]; exists {
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continue
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}
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if err := migrateImage(v1ID, root, ls, is, ms, mappings); err != nil {
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continue
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}
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}
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return nil
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}
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func migrateContainers(root string, ls graphIDMounter, is image.Store, imageMappings map[string]image.ID) error {
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containersDir := filepath.Join(root, containersDirName)
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dir, err := ioutil.ReadDir(containersDir)
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if err != nil {
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return err
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}
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for _, v := range dir {
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id := v.Name()
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if _, err := os.Stat(filepath.Join(containersDir, id, configFileName)); err == nil {
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continue
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}
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containerJSON, err := ioutil.ReadFile(filepath.Join(containersDir, id, configFileNameLegacy))
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if err != nil {
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logrus.Errorf("migrate container error: %v", err)
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continue
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}
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var c map[string]*json.RawMessage
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if err := json.Unmarshal(containerJSON, &c); err != nil {
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logrus.Errorf("migrate container error: %v", err)
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continue
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}
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imageStrJSON, ok := c["Image"]
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if !ok {
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return fmt.Errorf("invalid container configuration for %v", id)
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}
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var image string
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if err := json.Unmarshal([]byte(*imageStrJSON), &image); err != nil {
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logrus.Errorf("migrate container error: %v", err)
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continue
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}
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imageID, ok := imageMappings[image]
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if !ok {
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logrus.Errorf("image not migrated %v", imageID) // non-fatal error
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continue
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}
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c["Image"] = rawJSON(imageID)
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containerJSON, err = json.Marshal(c)
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if err != nil {
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return err
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}
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if err := ioutil.WriteFile(filepath.Join(containersDir, id, configFileName), containerJSON, 0600); err != nil {
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return err
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}
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img, err := is.Get(imageID)
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if err != nil {
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return err
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}
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if err := ls.CreateRWLayerByGraphID(id, id, img.RootFS.ChainID()); err != nil {
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logrus.Errorf("migrate container error: %v", err)
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continue
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}
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logrus.Infof("migrated container %s to point to %s", id, imageID)
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}
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return nil
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}
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type refAdder interface {
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AddTag(ref reference.Named, id image.ID, force bool) error
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AddDigest(ref reference.Canonical, id image.ID, force bool) error
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}
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func migrateRefs(root, driverName string, rs refAdder, mappings map[string]image.ID) error {
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migrationFile := filepath.Join(root, migrationTagsFileName)
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if _, err := os.Lstat(migrationFile); !os.IsNotExist(err) {
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return err
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}
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type repositories struct {
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Repositories map[string]map[string]string
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}
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var repos repositories
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f, err := os.Open(filepath.Join(root, repositoriesFilePrefixLegacy+driverName))
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if err != nil {
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if os.IsNotExist(err) {
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return nil
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}
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return err
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}
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defer f.Close()
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if err := json.NewDecoder(f).Decode(&repos); err != nil {
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return err
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}
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for name, repo := range repos.Repositories {
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for tag, id := range repo {
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if strongID, exists := mappings[id]; exists {
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ref, err := reference.WithName(name)
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if err != nil {
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logrus.Errorf("migrate tags: invalid name %q, %q", name, err)
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continue
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}
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if dgst, err := digest.ParseDigest(tag); err == nil {
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canonical, err := reference.WithDigest(ref, dgst)
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if err != nil {
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logrus.Errorf("migrate tags: invalid digest %q, %q", dgst, err)
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continue
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}
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if err := rs.AddDigest(canonical, strongID, false); err != nil {
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logrus.Errorf("can't migrate digest %q for %q, err: %q", ref.String(), strongID, err)
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}
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} else {
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tagRef, err := reference.WithTag(ref, tag)
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if err != nil {
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logrus.Errorf("migrate tags: invalid tag %q, %q", tag, err)
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continue
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}
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if err := rs.AddTag(tagRef, strongID, false); err != nil {
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logrus.Errorf("can't migrate tag %q for %q, err: %q", ref.String(), strongID, err)
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}
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}
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logrus.Infof("migrated tag %s:%s to point to %s", name, tag, strongID)
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}
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}
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}
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mf, err := os.Create(migrationFile)
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if err != nil {
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return err
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}
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mf.Close()
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return nil
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}
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func getParent(confDir string) (string, error) {
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jsonFile := filepath.Join(confDir, "json")
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imageJSON, err := ioutil.ReadFile(jsonFile)
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if err != nil {
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return "", err
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}
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var parent struct {
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Parent string
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ParentID digest.Digest `json:"parent_id"`
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}
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if err := json.Unmarshal(imageJSON, &parent); err != nil {
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return "", err
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}
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if parent.Parent == "" && parent.ParentID != "" { // v1.9
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parent.Parent = parent.ParentID.Hex()
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}
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// compatibilityID for parent
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parentCompatibilityID, err := ioutil.ReadFile(filepath.Join(confDir, "parent"))
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if err == nil && len(parentCompatibilityID) > 0 {
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parent.Parent = string(parentCompatibilityID)
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}
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return parent.Parent, nil
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}
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func migrateImage(id, root string, ls graphIDRegistrar, is image.Store, ms metadata.Store, mappings map[string]image.ID) (err error) {
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defer func() {
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if err != nil {
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logrus.Errorf("migration failed for %v, err: %v", id, err)
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}
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}()
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parent, err := getParent(filepath.Join(root, graphDirName, id))
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if err != nil {
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return err
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}
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var parentID image.ID
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if parent != "" {
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var exists bool
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if parentID, exists = mappings[parent]; !exists {
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if err := migrateImage(parent, root, ls, is, ms, mappings); err != nil {
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// todo: fail or allow broken chains?
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return err
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}
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parentID = mappings[parent]
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}
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}
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rootFS := image.NewRootFS()
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var history []image.History
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if parentID != "" {
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parentImg, err := is.Get(parentID)
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if err != nil {
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return err
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}
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rootFS = parentImg.RootFS
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history = parentImg.History
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}
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diffIDData, err := ioutil.ReadFile(filepath.Join(root, graphDirName, id, migrationDiffIDFileName))
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if err != nil {
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return err
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}
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diffID, err := digest.ParseDigest(string(diffIDData))
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if err != nil {
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return err
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}
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sizeStr, err := ioutil.ReadFile(filepath.Join(root, graphDirName, id, migrationSizeFileName))
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if err != nil {
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return err
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}
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size, err := strconv.ParseInt(string(sizeStr), 10, 64)
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if err != nil {
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return err
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}
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layer, err := ls.RegisterByGraphID(id, rootFS.ChainID(), layer.DiffID(diffID), filepath.Join(root, graphDirName, id, migrationTarDataFileName), size)
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if err != nil {
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return err
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}
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logrus.Infof("migrated layer %s to %s", id, layer.DiffID())
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jsonFile := filepath.Join(root, graphDirName, id, "json")
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imageJSON, err := ioutil.ReadFile(jsonFile)
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if err != nil {
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return err
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}
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h, err := imagev1.HistoryFromConfig(imageJSON, false)
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if err != nil {
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return err
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}
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history = append(history, h)
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rootFS.Append(layer.DiffID())
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config, err := imagev1.MakeConfigFromV1Config(imageJSON, rootFS, history)
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if err != nil {
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return err
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}
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strongID, err := is.Create(config)
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if err != nil {
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return err
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}
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logrus.Infof("migrated image %s to %s", id, strongID)
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if parentID != "" {
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if err := is.SetParent(strongID, parentID); err != nil {
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return err
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}
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}
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checksum, err := ioutil.ReadFile(filepath.Join(root, graphDirName, id, "checksum"))
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if err == nil { // best effort
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dgst, err := digest.ParseDigest(string(checksum))
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if err == nil {
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V2MetadataService := metadata.NewV2MetadataService(ms)
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V2MetadataService.Add(layer.DiffID(), metadata.V2Metadata{Digest: dgst})
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}
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}
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_, err = ls.Release(layer)
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if err != nil {
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return err
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}
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mappings[id] = strongID
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return
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}
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func rawJSON(value interface{}) *json.RawMessage {
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jsonval, err := json.Marshal(value)
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if err != nil {
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return nil
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}
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return (*json.RawMessage)(&jsonval)
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}
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