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content: change Writer/ReaderAt to take OCI

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This change allows implementations to resolve the location of the actual data
using OCI descriptor fields such as MediaType.

No OCI descriptor field is written to the store.

No change on gRPC API.

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
This commit is contained in:
Akihiro Suda
2018-05-21 16:31:26 +09:00
parent e4ad710ce8
commit d88de4a34f
32 changed files with 279 additions and 169 deletions
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39
content/content.go
View File

@@ -22,6 +22,7 @@ import (
"time"
"github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)
// ReaderAt extends the standard io.ReaderAt interface with reporting of Size and io.Closer
@@ -33,12 +34,16 @@ type ReaderAt interface {
// Provider provides a reader interface for specific content
type Provider interface {
ReaderAt(ctx context.Context, dgst digest.Digest) (ReaderAt, error)
// ReaderAt only requires desc.Digest to be set.
// Other fields in the descriptor may be used internally for resolving
// the location of the actual data.
ReaderAt(ctx context.Context, dec ocispec.Descriptor) (ReaderAt, error)
}
// Ingester writes content
type Ingester interface {
Writer(ctx context.Context, ref string, size int64, expected digest.Digest) (Writer, error)
// Some implementations require WithRef to be included in opts.
Writer(ctx context.Context, opts ...WriterOpt) (Writer, error)
}
// Info holds content specific information
@@ -142,3 +147,33 @@ func WithLabels(labels map[string]string) Opt {
return nil
}
}
// WriterOpts is internally used by WriterOpt.
type WriterOpts struct {
Ref string
Desc ocispec.Descriptor
}
// WriterOpt is used for passing options to Ingester.Writer.
type WriterOpt func(*WriterOpts) error
// WithDescriptor specifies an OCI descriptor.
// Writer may optionally use the descriptor internally for resolving
// the location of the actual data.
// Write does not require any field of desc to be set.
// If the data size is unknown, desc.Size should be set to 0.
// Some implementations may also accept negative values as "unknown".
func WithDescriptor(desc ocispec.Descriptor) WriterOpt {
return func(opts *WriterOpts) error {
opts.Desc = desc
return nil
}
}
// WithRef specifies a ref string.
func WithRef(ref string) WriterOpt {
return func(opts *WriterOpts) error {
opts.Ref = ref
return nil
}
}

15
content/helpers.go
View File

@@ -26,6 +26,7 @@ import (
"github.com/containerd/containerd/errdefs"
"github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
)
@@ -45,8 +46,8 @@ func NewReader(ra ReaderAt) io.Reader {
// ReadBlob retrieves the entire contents of the blob from the provider.
//
// Avoid using this for large blobs, such as layers.
func ReadBlob(ctx context.Context, provider Provider, dgst digest.Digest) ([]byte, error) {
ra, err := provider.ReaderAt(ctx, dgst)
func ReadBlob(ctx context.Context, provider Provider, desc ocispec.Descriptor) ([]byte, error) {
ra, err := provider.ReaderAt(ctx, desc)
if err != nil {
return nil, err
}
@@ -65,8 +66,8 @@ func ReadBlob(ctx context.Context, provider Provider, dgst digest.Digest) ([]byt
// This is useful when the digest and size are known beforehand.
//
// Copy is buffered, so no need to wrap reader in buffered io.
func WriteBlob(ctx context.Context, cs Ingester, ref string, r io.Reader, size int64, expected digest.Digest, opts ...Opt) error {
cw, err := OpenWriter(ctx, cs, ref, size, expected)
func WriteBlob(ctx context.Context, cs Ingester, ref string, r io.Reader, desc ocispec.Descriptor, opts ...Opt) error {
cw, err := OpenWriter(ctx, cs, WithRef(ref), WithDescriptor(desc))
if err != nil {
if !errdefs.IsAlreadyExists(err) {
return err
@@ -76,19 +77,19 @@ func WriteBlob(ctx context.Context, cs Ingester, ref string, r io.Reader, size i
}
defer cw.Close()
return Copy(ctx, cw, r, size, expected, opts...)
return Copy(ctx, cw, r, desc.Size, desc.Digest, opts...)
}
// OpenWriter opens a new writer for the given reference, retrying if the writer
// is locked until the reference is available or returns an error.
func OpenWriter(ctx context.Context, cs Ingester, ref string, size int64, expected digest.Digest) (Writer, error) {
func OpenWriter(ctx context.Context, cs Ingester, opts ...WriterOpt) (Writer, error) {
var (
cw Writer
err error
retry = 16
)
for {
cw, err = cs.Writer(ctx, ref, size, expected)
cw, err = cs.Writer(ctx, opts...)
if err != nil {
if !errdefs.IsUnavailable(err) {
return nil, err

28
content/local/store.go
View File

@@ -34,6 +34,7 @@ import (
"github.com/containerd/containerd/filters"
"github.com/containerd/containerd/log"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
)
@@ -119,15 +120,15 @@ func (s *store) info(dgst digest.Digest, fi os.FileInfo, labels map[string]strin
}
// ReaderAt returns an io.ReaderAt for the blob.
func (s *store) ReaderAt(ctx context.Context, dgst digest.Digest) (content.ReaderAt, error) {
p := s.blobPath(dgst)
func (s *store) ReaderAt(ctx context.Context, desc ocispec.Descriptor) (content.ReaderAt, error) {
p := s.blobPath(desc.Digest)
fi, err := os.Stat(p)
if err != nil {
if !os.IsNotExist(err) {
return nil, err
}
return nil, errors.Wrapf(errdefs.ErrNotFound, "blob %s expected at %s", dgst, p)
return nil, errors.Wrapf(errdefs.ErrNotFound, "blob %s expected at %s", desc.Digest, p)
}
fp, err := os.Open(p)
@@ -136,7 +137,7 @@ func (s *store) ReaderAt(ctx context.Context, dgst digest.Digest) (content.Reade
return nil, err
}
return nil, errors.Wrapf(errdefs.ErrNotFound, "blob %s expected at %s", dgst, p)
return nil, errors.Wrapf(errdefs.ErrNotFound, "blob %s expected at %s", desc.Digest, p)
}
return sizeReaderAt{size: fi.Size(), fp: fp}, nil
@@ -400,11 +401,22 @@ func (s *store) total(ingestPath string) int64 {
// ref at a time.
//
// The argument `ref` is used to uniquely identify a long-lived writer transaction.
func (s *store) Writer(ctx context.Context, ref string, total int64, expected digest.Digest) (content.Writer, error) {
func (s *store) Writer(ctx context.Context, opts ...content.WriterOpt) (content.Writer, error) {
var wOpts content.WriterOpts
for _, opt := range opts {
if err := opt(&wOpts); err != nil {
return nil, err
}
}
// TODO(AkihiroSuda): we could create a random string or one calculated based on the context
// https://github.com/containerd/containerd/issues/2129#issuecomment-380255019
if wOpts.Ref == "" {
return nil, errors.Wrap(errdefs.ErrInvalidArgument, "ref must not be empty")
}
var lockErr error
for count := uint64(0); count < 10; count++ {
time.Sleep(time.Millisecond * time.Duration(rand.Intn(1<<count)))
if err := tryLock(ref); err != nil {
if err := tryLock(wOpts.Ref); err != nil {
if !errdefs.IsUnavailable(err) {
return nil, err
}
@@ -420,9 +432,9 @@ func (s *store) Writer(ctx context.Context, ref string, total int64, expected di
return nil, lockErr
}
w, err := s.writer(ctx, ref, total, expected)
w, err := s.writer(ctx, wOpts.Ref, wOpts.Desc.Size, wOpts.Desc.Digest)
if err != nil {
unlock(ref)
unlock(wOpts.Ref)
return nil, err
}

24
content/local/store_test.go
View File

@@ -39,6 +39,7 @@ import (
"github.com/containerd/containerd/pkg/testutil"
"github.com/gotestyourself/gotestyourself/assert"
"github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)
type memoryLabelStore struct {
@@ -108,7 +109,7 @@ func TestContentWriter(t *testing.T) {
t.Fatal("ingest dir should be created", err)
}
cw, err := cs.Writer(ctx, "myref", 0, "")
cw, err := cs.Writer(ctx, content.WithRef("myref"))
if err != nil {
t.Fatal(err)
}
@@ -117,13 +118,13 @@ func TestContentWriter(t *testing.T) {
}
// reopen, so we can test things
cw, err = cs.Writer(ctx, "myref", 0, "")
cw, err = cs.Writer(ctx, content.WithRef("myref"))
if err != nil {
t.Fatal(err)
}
// make sure that second resume also fails
if _, err = cs.Writer(ctx, "myref", 0, ""); err == nil {
if _, err = cs.Writer(ctx, content.WithRef("myref")); err == nil {
// TODO(stevvooe): This also works across processes. Need to find a way
// to test that, as well.
t.Fatal("no error on second resume")
@@ -166,7 +167,7 @@ func TestContentWriter(t *testing.T) {
t.Fatal(err)
}
cw, err = cs.Writer(ctx, "aref", 0, "")
cw, err = cs.Writer(ctx, content.WithRef("aref"))
if err != nil {
t.Fatal(err)
}
@@ -346,7 +347,8 @@ func checkBlobPath(t *testing.T, cs content.Store, dgst digest.Digest) string {
}
func checkWrite(ctx context.Context, t checker, cs content.Store, dgst digest.Digest, p []byte) digest.Digest {
if err := content.WriteBlob(ctx, cs, dgst.String(), bytes.NewReader(p), int64(len(p)), dgst); err != nil {
if err := content.WriteBlob(ctx, cs, dgst.String(), bytes.NewReader(p),
ocispec.Descriptor{Size: int64(len(p)), Digest: dgst}); err != nil {
t.Fatal(err)
}
@@ -365,25 +367,25 @@ func TestWriterTruncateRecoversFromIncompleteWrite(t *testing.T) {
defer cancel()
ref := "ref"
content := []byte("this is the content")
total := int64(len(content))
contentB := []byte("this is the content")
total := int64(len(contentB))
setupIncompleteWrite(ctx, t, cs, ref, total)
writer, err := cs.Writer(ctx, ref, total, "")
writer, err := cs.Writer(ctx, content.WithRef(ref), content.WithDescriptor(ocispec.Descriptor{Size: total}))
assert.NilError(t, err)
assert.NilError(t, writer.Truncate(0))
_, err = writer.Write(content)
_, err = writer.Write(contentB)
assert.NilError(t, err)
dgst := digest.FromBytes(content)
dgst := digest.FromBytes(contentB)
err = writer.Commit(ctx, total, dgst)
assert.NilError(t, err)
}
func setupIncompleteWrite(ctx context.Context, t *testing.T, cs content.Store, ref string, total int64) {
writer, err := cs.Writer(ctx, ref, total, "")
writer, err := cs.Writer(ctx, content.WithRef(ref), content.WithDescriptor(ocispec.Descriptor{Size: total}))
assert.NilError(t, err)
_, err = writer.Write([]byte("bad data"))

21
content/proxy/content_store.go
View File

@@ -25,6 +25,7 @@ import (
"github.com/containerd/containerd/errdefs"
protobuftypes "github.com/gogo/protobuf/types"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)
type proxyContentStore struct {
@@ -88,15 +89,16 @@ func (pcs *proxyContentStore) Delete(ctx context.Context, dgst digest.Digest) er
return nil
}
func (pcs *proxyContentStore) ReaderAt(ctx context.Context, dgst digest.Digest) (content.ReaderAt, error) {
i, err := pcs.Info(ctx, dgst)
// ReaderAt ignores MediaType.
func (pcs *proxyContentStore) ReaderAt(ctx context.Context, desc ocispec.Descriptor) (content.ReaderAt, error) {
i, err := pcs.Info(ctx, desc.Digest)
if err != nil {
return nil, err
}
return &remoteReaderAt{
ctx: ctx,
digest: dgst,
digest: desc.Digest,
size: i.Size,
client: pcs.client,
}, nil
@@ -157,14 +159,21 @@ func (pcs *proxyContentStore) ListStatuses(ctx context.Context, filters ...strin
return statuses, nil
}
func (pcs *proxyContentStore) Writer(ctx context.Context, ref string, size int64, expected digest.Digest) (content.Writer, error) {
wrclient, offset, err := pcs.negotiate(ctx, ref, size, expected)
// Writer ignores MediaType.
func (pcs *proxyContentStore) Writer(ctx context.Context, opts ...content.WriterOpt) (content.Writer, error) {
var wOpts content.WriterOpts
for _, opt := range opts {
if err := opt(&wOpts); err != nil {
return nil, err
}
}
wrclient, offset, err := pcs.negotiate(ctx, wOpts.Ref, wOpts.Desc.Size, wOpts.Desc.Digest)
if err != nil {
return nil, errdefs.FromGRPC(err)
}
return &remoteWriter{
ref: ref,
ref: wOpts.Ref,
client: wrclient,
offset: offset,
}, nil

35
content/testsuite/testsuite.go
View File

@@ -33,6 +33,7 @@ import (
"github.com/containerd/containerd/pkg/testutil"
"github.com/gotestyourself/gotestyourself/assert"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
)
@@ -122,28 +123,28 @@ var labels = map[string]string{
func checkContentStoreWriter(ctx context.Context, t *testing.T, cs content.Store) {
c1, d1 := createContent(256)
w1, err := cs.Writer(ctx, "c1", 0, "")
w1, err := cs.Writer(ctx, content.WithRef("c1"))
if err != nil {
t.Fatal(err)
}
defer w1.Close()
c2, d2 := createContent(256)
w2, err := cs.Writer(ctx, "c2", int64(len(c2)), "")
w2, err := cs.Writer(ctx, content.WithRef("c2"), content.WithDescriptor(ocispec.Descriptor{Size: int64(len(c2))}))
if err != nil {
t.Fatal(err)
}
defer w2.Close()
c3, d3 := createContent(256)
w3, err := cs.Writer(ctx, "c3", 0, d3)
w3, err := cs.Writer(ctx, content.WithRef("c3"), content.WithDescriptor(ocispec.Descriptor{Digest: d3}))
if err != nil {
t.Fatal(err)
}
defer w3.Close()
c4, d4 := createContent(256)
w4, err := cs.Writer(ctx, "c4", int64(len(c4)), d4)
w4, err := cs.Writer(ctx, content.WithRef("c4"), content.WithDescriptor(ocispec.Descriptor{Size: int64(len(c4)), Digest: d4}))
if err != nil {
t.Fatal(err)
}
@@ -226,7 +227,7 @@ func checkResumeWriter(ctx context.Context, t *testing.T, cs content.Store) {
)
preStart := time.Now()
w1, err := cs.Writer(ctx, ref, 256, dgst)
w1, err := cs.Writer(ctx, content.WithRef(ref), content.WithDescriptor(ocispec.Descriptor{Size: 256, Digest: dgst}))
if err != nil {
t.Fatal(err)
}
@@ -247,7 +248,7 @@ func checkResumeWriter(ctx context.Context, t *testing.T, cs content.Store) {
checkStatus(t, w1, expected, dgstFirst, preStart, postStart, preUpdate, postUpdate)
assert.NilError(t, w1.Close(), "close first writer")
w2, err := cs.Writer(ctx, ref, 256, dgst)
w2, err := cs.Writer(ctx, content.WithRef(ref), content.WithDescriptor(ocispec.Descriptor{Size: 256, Digest: dgst}))
if err != nil {
t.Fatal(err)
}
@@ -284,7 +285,7 @@ func checkUpdateStatus(ctx context.Context, t *testing.T, cs content.Store) {
c1, d1 := createContent(256)
preStart := time.Now()
w1, err := cs.Writer(ctx, "c1", 256, d1)
w1, err := cs.Writer(ctx, content.WithRef("c1"), content.WithDescriptor(ocispec.Descriptor{Size: 256, Digest: d1}))
if err != nil {
t.Fatal(err)
}
@@ -352,7 +353,7 @@ func checkUpdateStatus(ctx context.Context, t *testing.T, cs content.Store) {
func checkLabels(ctx context.Context, t *testing.T, cs content.Store) {
c1, d1 := createContent(256)
w1, err := cs.Writer(ctx, "c1", 256, d1)
w1, err := cs.Writer(ctx, content.WithRef("c1"), content.WithDescriptor(ocispec.Descriptor{Size: 256, Digest: d1}))
if err != nil {
t.Fatal(err)
}
@@ -427,7 +428,7 @@ func checkResume(rf func(context.Context, content.Writer, []byte, int64, int64,
limit := int64(float64(size) * tp)
ref := fmt.Sprintf("ref-%d-%d", i, j)
w, err := cs.Writer(ctx, ref, size, d)
w, err := cs.Writer(ctx, content.WithRef(ref), content.WithDescriptor(ocispec.Descriptor{Size: size, Digest: d}))
if err != nil {
t.Fatal(err)
}
@@ -441,7 +442,7 @@ func checkResume(rf func(context.Context, content.Writer, []byte, int64, int64,
t.Fatal(err)
}
w, err = cs.Writer(ctx, ref, size, d)
w, err = cs.Writer(ctx, content.WithRef(ref), content.WithDescriptor(ocispec.Descriptor{Size: size, Digest: d}))
if err != nil {
t.Fatal(err)
}
@@ -530,7 +531,7 @@ func checkSmallBlob(ctx context.Context, t *testing.T, store content.Store) {
blobSize := int64(len(blob))
blobDigest := digest.FromBytes(blob)
// test write
w, err := store.Writer(ctx, t.Name(), blobSize, blobDigest)
w, err := store.Writer(ctx, content.WithRef(t.Name()), content.WithDescriptor(ocispec.Descriptor{Size: blobSize, Digest: blobDigest}))
if err != nil {
t.Fatal(err)
}
@@ -545,7 +546,7 @@ func checkSmallBlob(ctx context.Context, t *testing.T, store content.Store) {
}
// test read.
readSize := blobSize + 1
ra, err := store.ReaderAt(ctx, blobDigest)
ra, err := store.ReaderAt(ctx, ocispec.Descriptor{Digest: blobDigest})
if err != nil {
t.Fatal(err)
}
@@ -575,7 +576,7 @@ func checkCrossNSShare(ctx context.Context, t *testing.T, cs content.Store) {
ref := fmt.Sprintf("ref-%d", size)
t1 := time.Now()
if err := content.WriteBlob(ctx, cs, ref, bytes.NewReader(b), size, d); err != nil {
if err := content.WriteBlob(ctx, cs, ref, bytes.NewReader(b), ocispec.Descriptor{Size: size, Digest: d}); err != nil {
t.Fatal(err)
}
@@ -585,7 +586,7 @@ func checkCrossNSShare(ctx context.Context, t *testing.T, cs content.Store) {
}
defer done(ctx2)
w, err := cs.Writer(ctx2, ref, size, d)
w, err := cs.Writer(ctx2, content.WithRef(ref), content.WithDescriptor(ocispec.Descriptor{Size: size, Digest: d}))
if err != nil {
t.Fatal(err)
}
@@ -626,7 +627,7 @@ func checkCrossNSAppend(ctx context.Context, t *testing.T, cs content.Store) {
ref := fmt.Sprintf("ref-%d", size)
t1 := time.Now()
if err := content.WriteBlob(ctx, cs, ref, bytes.NewReader(b), size, d); err != nil {
if err := content.WriteBlob(ctx, cs, ref, bytes.NewReader(b), ocispec.Descriptor{Size: size, Digest: d}); err != nil {
t.Fatal(err)
}
@@ -643,7 +644,7 @@ func checkCrossNSAppend(ctx context.Context, t *testing.T, cs content.Store) {
copy(b2[size:], extra)
d2 := digest.FromBytes(b2)
w, err := cs.Writer(ctx2, ref, size, d)
w, err := cs.Writer(ctx2, content.WithRef(ref), content.WithDescriptor(ocispec.Descriptor{Size: size, Digest: d}))
if err != nil {
t.Fatal(err)
}
@@ -768,7 +769,7 @@ func checkContent(ctx context.Context, cs content.Store, d digest.Digest, expect
return err
}
b, err := content.ReadBlob(ctx, cs, d)
b, err := content.ReadBlob(ctx, cs, ocispec.Descriptor{Digest: d})
if err != nil {
return errors.Wrap(err, "failed to read blob")
}