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moby--moby/graph/pull_v2.go

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package graph
import (
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"github.com/Sirupsen/logrus"
"github.com/docker/distribution"
"github.com/docker/distribution/digest"
"github.com/docker/distribution/manifest"
"github.com/docker/docker/image"
"github.com/docker/docker/pkg/progressreader"
"github.com/docker/docker/pkg/streamformatter"
"github.com/docker/docker/pkg/stringid"
"github.com/docker/docker/registry"
"github.com/docker/docker/trust"
"github.com/docker/docker/utils"
"github.com/docker/libtrust"
"golang.org/x/net/context"
)
type v2Puller struct {
*TagStore
endpoint registry.APIEndpoint
config *ImagePullConfig
sf *streamformatter.StreamFormatter
repoInfo *registry.RepositoryInfo
repo distribution.Repository
sessionID string
}
func (p *v2Puller) Pull(tag string) (fallback bool, err error) {
// TODO(tiborvass): was ReceiveTimeout
p.repo, err = NewV2Repository(p.repoInfo, p.endpoint, p.config.MetaHeaders, p.config.AuthConfig)
if err != nil {
logrus.Debugf("Error getting v2 registry: %v", err)
return true, err
}
p.sessionID = stringid.GenerateRandomID()
if err := p.pullV2Repository(tag); err != nil {
if registry.ContinueOnError(err) {
logrus.Debugf("Error trying v2 registry: %v", err)
return true, err
}
return false, err
}
return false, nil
}
func (p *v2Puller) pullV2Repository(tag string) (err error) {
var tags []string
taggedName := p.repoInfo.LocalName
if len(tag) > 0 {
tags = []string{tag}
taggedName = utils.ImageReference(p.repoInfo.LocalName, tag)
} else {
var err error
manSvc, err := p.repo.Manifests(context.Background())
if err != nil {
return err
}
tags, err = manSvc.Tags()
if err != nil {
return err
}
}
broadcaster, found := p.poolAdd("pull", taggedName)
if found {
// Another pull of the same repository is already taking place; just wait for it to finish
broadcaster.Add(p.config.OutStream)
broadcaster.Wait()
return nil
}
defer p.poolRemove("pull", taggedName)
broadcaster.Add(p.config.OutStream)
var layersDownloaded bool
for _, tag := range tags {
// pulledNew is true if either new layers were downloaded OR if existing images were newly tagged
// TODO(tiborvass): should we change the name of `layersDownload`? What about message in WriteStatus?
pulledNew, err := p.pullV2Tag(broadcaster, tag, taggedName)
if err != nil {
return err
}
layersDownloaded = layersDownloaded || pulledNew
}
writeStatus(taggedName, broadcaster, p.sf, layersDownloaded)
return nil
}
// downloadInfo is used to pass information from download to extractor
type downloadInfo struct {
img *image.Image
tmpFile *os.File
digest digest.Digest
layer distribution.ReadSeekCloser
size int64
err chan error
out io.Writer // Download progress is written here.
}
type errVerification struct{}
func (errVerification) Error() string { return "verification failed" }
func (p *v2Puller) download(di *downloadInfo) {
logrus.Debugf("pulling blob %q to %s", di.digest, di.img.ID)
out := di.out
broadcaster, found := p.poolAdd("pull", "img:"+di.img.ID)
if found {
broadcaster.Add(out)
broadcaster.Wait()
out.Write(p.sf.FormatProgress(stringid.TruncateID(di.img.ID), "Download complete", nil))
di.err <- nil
return
}
broadcaster.Add(out)
defer p.poolRemove("pull", "img:"+di.img.ID)
tmpFile, err := ioutil.TempFile("", "GetImageBlob")
if err != nil {
di.err <- err
return
}
di.tmpFile = tmpFile
blobs := p.repo.Blobs(context.Background())
desc, err := blobs.Stat(context.Background(), di.digest)
if err != nil {
logrus.Debugf("Error statting layer: %v", err)
di.err <- err
return
}
di.size = desc.Size
layerDownload, err := blobs.Open(context.Background(), di.digest)
if err != nil {
logrus.Debugf("Error fetching layer: %v", err)
di.err <- err
return
}
defer layerDownload.Close()
verifier, err := digest.NewDigestVerifier(di.digest)
if err != nil {
di.err <- err
return
}
reader := progressreader.New(progressreader.Config{
In: ioutil.NopCloser(io.TeeReader(layerDownload, verifier)),
Out: broadcaster,
Formatter: p.sf,
Size: di.size,
NewLines: false,
ID: stringid.TruncateID(di.img.ID),
Action: "Downloading",
})
io.Copy(tmpFile, reader)
broadcaster.Write(p.sf.FormatProgress(stringid.TruncateID(di.img.ID), "Verifying Checksum", nil))
if !verifier.Verified() {
err = fmt.Errorf("filesystem layer verification failed for digest %s", di.digest)
logrus.Error(err)
di.err <- err
return
}
broadcaster.Write(p.sf.FormatProgress(stringid.TruncateID(di.img.ID), "Download complete", nil))
logrus.Debugf("Downloaded %s to tempfile %s", di.img.ID, tmpFile.Name())
di.layer = layerDownload
di.err <- nil
}
func (p *v2Puller) pullV2Tag(out io.Writer, tag, taggedName string) (verified bool, err error) {
logrus.Debugf("Pulling tag from V2 registry: %q", tag)
manSvc, err := p.repo.Manifests(context.Background())
if err != nil {
return false, err
}
manifest, err := manSvc.GetByTag(tag)
if err != nil {
return false, err
}
verified, err = p.validateManifest(manifest, tag)
if err != nil {
return false, err
}
if verified {
logrus.Printf("Image manifest for %s has been verified", taggedName)
}
// By using a pipeWriter for each of the downloads to write their progress
// to, we can avoid an issue where this function returns an error but
// leaves behind running download goroutines. By splitting the writer
// with a pipe, we can close the pipe if there is any error, consequently
// causing each download to cancel due to an error writing to this pipe.
pipeReader, pipeWriter := io.Pipe()
go func() {
if _, err := io.Copy(out, pipeReader); err != nil {
logrus.Errorf("error copying from layer download progress reader: %s", err)
if err := pipeReader.CloseWithError(err); err != nil {
logrus.Errorf("error closing the progress reader: %s", err)
}
}
}()
defer func() {
if err != nil {
// All operations on the pipe are synchronous. This call will wait
// until all current readers/writers are done using the pipe then
// set the error. All successive reads/writes will return with this
// error.
pipeWriter.CloseWithError(errors.New("download canceled"))
} else {
// If no error then just close the pipe.
pipeWriter.Close()
}
}()
out.Write(p.sf.FormatStatus(tag, "Pulling from %s", p.repo.Name()))
var downloads []*downloadInfo
var layerIDs []string
defer func() {
p.graph.Release(p.sessionID, layerIDs...)
}()
for i := len(manifest.FSLayers) - 1; i >= 0; i-- {
img, err := image.NewImgJSON([]byte(manifest.History[i].V1Compatibility))
if err != nil {
logrus.Debugf("error getting image v1 json: %v", err)
return false, err
}
p.graph.Retain(p.sessionID, img.ID)
layerIDs = append(layerIDs, img.ID)
// Check if exists
if p.graph.Exists(img.ID) {
logrus.Debugf("Image already exists: %s", img.ID)
out.Write(p.sf.FormatProgress(stringid.TruncateID(img.ID), "Already exists", nil))
continue
}
out.Write(p.sf.FormatProgress(stringid.TruncateID(img.ID), "Pulling fs layer", nil))
d := &downloadInfo{
img: img,
digest: manifest.FSLayers[i].BlobSum,
// TODO: seems like this chan buffer solved hanging problem in go1.5,
// this can indicate some deeper problem that somehow we never take
// error from channel in loop below
err: make(chan error, 1),
out: pipeWriter,
}
downloads = append(downloads, d)
go p.download(d)
}
// run clean for all downloads to prevent leftovers
for _, d := range downloads {
defer func(d *downloadInfo) {
if d.tmpFile != nil {
d.tmpFile.Close()
if err := os.RemoveAll(d.tmpFile.Name()); err != nil {
logrus.Errorf("Failed to remove temp file: %s", d.tmpFile.Name())
}
}
}(d)
}
var tagUpdated bool
for _, d := range downloads {
if err := <-d.err; err != nil {
return false, err
}
if d.layer == nil {
continue
}
// if tmpFile is empty assume download and extracted elsewhere
d.tmpFile.Seek(0, 0)
reader := progressreader.New(progressreader.Config{
In: d.tmpFile,
Out: out,
Formatter: p.sf,
Size: d.size,
NewLines: false,
ID: stringid.TruncateID(d.img.ID),
Action: "Extracting",
})
err = p.graph.Register(d.img, reader)
if err != nil {
return false, err
}
if err := p.graph.SetDigest(d.img.ID, d.digest); err != nil {
return false, err
}
// FIXME: Pool release here for parallel tag pull (ensures any downloads block until fully extracted)
out.Write(p.sf.FormatProgress(stringid.TruncateID(d.img.ID), "Pull complete", nil))
tagUpdated = true
}
manifestDigest, _, err := digestFromManifest(manifest, p.repoInfo.LocalName)
if err != nil {
return false, err
}
// Check for new tag if no layers downloaded
if !tagUpdated {
repo, err := p.Get(p.repoInfo.LocalName)
if err != nil {
return false, err
}
if repo != nil {
if _, exists := repo[tag]; !exists {
tagUpdated = true
}
} else {
tagUpdated = true
}
}
if verified && tagUpdated {
out.Write(p.sf.FormatStatus(p.repo.Name()+":"+tag, "The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security."))
}
firstID := layerIDs[len(layerIDs)-1]
if utils.DigestReference(tag) {
// TODO(stevvooe): Ideally, we should always set the digest so we can
// use the digest whether we pull by it or not. Unfortunately, the tag
// store treats the digest as a separate tag, meaning there may be an
// untagged digest image that would seem to be dangling by a user.
if err = p.SetDigest(p.repoInfo.LocalName, tag, firstID); err != nil {
return false, err
}
} else {
// only set the repository/tag -> image ID mapping when pulling by tag (i.e. not by digest)
if err = p.Tag(p.repoInfo.LocalName, tag, firstID, true); err != nil {
return false, err
}
}
if manifestDigest != "" {
out.Write(p.sf.FormatStatus("", "Digest: %s", manifestDigest))
}
return tagUpdated, nil
}
// verifyTrustedKeys checks the keys provided against the trust store,
// ensuring that the provided keys are trusted for the namespace. The keys
// provided from this method must come from the signatures provided as part of
// the manifest JWS package, obtained from unpackSignedManifest or libtrust.
func (p *v2Puller) verifyTrustedKeys(namespace string, keys []libtrust.PublicKey) (verified bool, err error) {
if namespace[0] != '/' {
namespace = "/" + namespace
}
for _, key := range keys {
b, err := key.MarshalJSON()
if err != nil {
return false, fmt.Errorf("error marshalling public key: %s", err)
}
// Check key has read/write permission (0x03)
v, err := p.trustService.CheckKey(namespace, b, 0x03)
if err != nil {
vErr, ok := err.(trust.NotVerifiedError)
if !ok {
return false, fmt.Errorf("error running key check: %s", err)
}
logrus.Debugf("Key check result: %v", vErr)
}
verified = v
}
if verified {
logrus.Debug("Key check result: verified")
}
return
}
func (p *v2Puller) validateManifest(m *manifest.SignedManifest, tag string) (verified bool, err error) {
// If pull by digest, then verify the manifest digest. NOTE: It is
// important to do this first, before any other content validation. If the
// digest cannot be verified, don't even bother with those other things.
if manifestDigest, err := digest.ParseDigest(tag); err == nil {
verifier, err := digest.NewDigestVerifier(manifestDigest)
if err != nil {
return false, err
}
payload, err := m.Payload()
if err != nil {
return false, err
}
if _, err := verifier.Write(payload); err != nil {
return false, err
}
if !verifier.Verified() {
err := fmt.Errorf("image verification failed for digest %s", manifestDigest)
logrus.Error(err)
return false, err
}
}
// TODO(tiborvass): what's the usecase for having manifest == nil and err == nil ? Shouldn't be the error be "DoesNotExist" ?
if m == nil {
return false, fmt.Errorf("image manifest does not exist for tag %q", tag)
}
if m.SchemaVersion != 1 {
return false, fmt.Errorf("unsupported schema version %d for tag %q", m.SchemaVersion, tag)
}
if len(m.FSLayers) != len(m.History) {
return false, fmt.Errorf("length of history not equal to number of layers for tag %q", tag)
}
if len(m.FSLayers) == 0 {
return false, fmt.Errorf("no FSLayers in manifest for tag %q", tag)
}
keys, err := manifest.Verify(m)
if err != nil {
return false, fmt.Errorf("error verifying manifest for tag %q: %v", tag, err)
}
verified, err = p.verifyTrustedKeys(m.Name, keys)
if err != nil {
return false, fmt.Errorf("error verifying manifest keys: %v", err)
}
return verified, nil
}