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moby--moby/plugin/blobstore.go
Stephen J Day 7a85579917
*: use opencontainers/go-digest package
The `digest` data type, used throughout docker for image verification
and identity, has been broken out into `opencontainers/go-digest`. This
PR updates the dependencies and moves uses over to the new type.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2017-01-06 18:48:41 -08:00

182 lines
4.6 KiB
Go

package plugin
import (
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/distribution/xfer"
"github.com/docker/docker/image"
"github.com/docker/docker/layer"
"github.com/docker/docker/pkg/archive"
"github.com/docker/docker/pkg/progress"
"github.com/opencontainers/go-digest"
"github.com/pkg/errors"
"golang.org/x/net/context"
)
type blobstore interface {
New() (WriteCommitCloser, error)
Get(dgst digest.Digest) (io.ReadCloser, error)
Size(dgst digest.Digest) (int64, error)
}
type basicBlobStore struct {
path string
}
func newBasicBlobStore(p string) (*basicBlobStore, error) {
tmpdir := filepath.Join(p, "tmp")
if err := os.MkdirAll(tmpdir, 0700); err != nil {
return nil, errors.Wrapf(err, "failed to mkdir %v", p)
}
return &basicBlobStore{path: p}, nil
}
func (b *basicBlobStore) New() (WriteCommitCloser, error) {
f, err := ioutil.TempFile(filepath.Join(b.path, "tmp"), ".insertion")
if err != nil {
return nil, errors.Wrap(err, "failed to create temp file")
}
return newInsertion(f), nil
}
func (b *basicBlobStore) Get(dgst digest.Digest) (io.ReadCloser, error) {
return os.Open(filepath.Join(b.path, string(dgst.Algorithm()), dgst.Hex()))
}
func (b *basicBlobStore) Size(dgst digest.Digest) (int64, error) {
stat, err := os.Stat(filepath.Join(b.path, string(dgst.Algorithm()), dgst.Hex()))
if err != nil {
return 0, err
}
return stat.Size(), nil
}
func (b *basicBlobStore) gc(whitelist map[digest.Digest]struct{}) {
for _, alg := range []string{string(digest.Canonical)} {
items, err := ioutil.ReadDir(filepath.Join(b.path, alg))
if err != nil {
continue
}
for _, fi := range items {
if _, exists := whitelist[digest.Digest(alg+":"+fi.Name())]; !exists {
p := filepath.Join(b.path, alg, fi.Name())
err := os.RemoveAll(p)
logrus.Debugf("cleaned up blob %v: %v", p, err)
}
}
}
}
// WriteCommitCloser defines object that can be committed to blobstore.
type WriteCommitCloser interface {
io.WriteCloser
Commit() (digest.Digest, error)
}
type insertion struct {
io.Writer
f *os.File
digester digest.Digester
closed bool
}
func newInsertion(tempFile *os.File) *insertion {
digester := digest.Canonical.Digester()
return &insertion{f: tempFile, digester: digester, Writer: io.MultiWriter(tempFile, digester.Hash())}
}
func (i *insertion) Commit() (digest.Digest, error) {
p := i.f.Name()
d := filepath.Join(filepath.Join(p, "../../"))
i.f.Sync()
defer os.RemoveAll(p)
if err := i.f.Close(); err != nil {
return "", err
}
i.closed = true
dgst := i.digester.Digest()
if err := os.MkdirAll(filepath.Join(d, string(dgst.Algorithm())), 0700); err != nil {
return "", errors.Wrapf(err, "failed to mkdir %v", d)
}
if err := os.Rename(p, filepath.Join(d, string(dgst.Algorithm()), dgst.Hex())); err != nil {
return "", errors.Wrapf(err, "failed to rename %v", p)
}
return dgst, nil
}
func (i *insertion) Close() error {
if i.closed {
return nil
}
defer os.RemoveAll(i.f.Name())
return i.f.Close()
}
type downloadManager struct {
blobStore blobstore
tmpDir string
blobs []digest.Digest
configDigest digest.Digest
}
func (dm *downloadManager) Download(ctx context.Context, initialRootFS image.RootFS, layers []xfer.DownloadDescriptor, progressOutput progress.Output) (image.RootFS, func(), error) {
for _, l := range layers {
b, err := dm.blobStore.New()
if err != nil {
return initialRootFS, nil, err
}
defer b.Close()
rc, _, err := l.Download(ctx, progressOutput)
if err != nil {
return initialRootFS, nil, errors.Wrap(err, "failed to download")
}
defer rc.Close()
r := io.TeeReader(rc, b)
inflatedLayerData, err := archive.DecompressStream(r)
if err != nil {
return initialRootFS, nil, err
}
digester := digest.Canonical.Digester()
if _, err := archive.ApplyLayer(dm.tmpDir, io.TeeReader(inflatedLayerData, digester.Hash())); err != nil {
return initialRootFS, nil, err
}
initialRootFS.Append(layer.DiffID(digester.Digest()))
d, err := b.Commit()
if err != nil {
return initialRootFS, nil, err
}
dm.blobs = append(dm.blobs, d)
}
return initialRootFS, nil, nil
}
func (dm *downloadManager) Put(dt []byte) (digest.Digest, error) {
b, err := dm.blobStore.New()
if err != nil {
return "", err
}
defer b.Close()
n, err := b.Write(dt)
if err != nil {
return "", err
}
if n != len(dt) {
return "", io.ErrShortWrite
}
d, err := b.Commit()
dm.configDigest = d
return d, err
}
func (dm *downloadManager) Get(d digest.Digest) ([]byte, error) {
return nil, fmt.Errorf("digest not found")
}
func (dm *downloadManager) RootFSFromConfig(c []byte) (*image.RootFS, error) {
return configToRootFS(c)
}