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Adds new storagedriver.FileWriter interface

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Updates registry storage code to use this for better resumable writes.
Implements this interface for the following drivers:
 + Inmemory
 + Filesystem
 + S3
 + Azure

Signed-off-by: Brian Bland <brian.bland@docker.com>
This commit is contained in:
Brian Bland 2016-02-08 14:29:21 -08:00
parent 7adddecf0b
commit c69c8a3286
25 changed files with 1059 additions and 2488 deletions
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49
docs/storage/blobwriter.go
View file

@ -21,6 +21,7 @@ var (
// layerWriter is used to control the various aspects of resumable
// layer upload. It implements the LayerUpload interface.
type blobWriter struct {
ctx context.Context
blobStore *linkedBlobStore
id string
@ -28,9 +29,9 @@ type blobWriter struct {
digester digest.Digester
written int64 // track the contiguous write
// implementes io.WriteSeeker, io.ReaderFrom and io.Closer to satisfy
// LayerUpload Interface
fileWriter
fileWriter storagedriver.FileWriter
driver storagedriver.StorageDriver
path string
resumableDigestEnabled bool
}
@ -51,7 +52,7 @@ func (bw *blobWriter) StartedAt() time.Time {
func (bw *blobWriter) Commit(ctx context.Context, desc distribution.Descriptor) (distribution.Descriptor, error) {
context.GetLogger(ctx).Debug("(*blobWriter).Commit")
if err := bw.fileWriter.Close(); err != nil {
if err := bw.fileWriter.Commit(); err != nil {
return distribution.Descriptor{}, err
}
@ -84,6 +85,10 @@ func (bw *blobWriter) Commit(ctx context.Context, desc distribution.Descriptor)
// the writer and canceling the operation.
func (bw *blobWriter) Cancel(ctx context.Context) error {
context.GetLogger(ctx).Debug("(*blobWriter).Rollback")
if err := bw.fileWriter.Cancel(); err != nil {
return err
}
if err := bw.removeResources(ctx); err != nil {
return err
}
@ -92,15 +97,19 @@ func (bw *blobWriter) Cancel(ctx context.Context) error {
return nil
}
func (bw *blobWriter) Size() int64 {
return bw.fileWriter.Size()
}
func (bw *blobWriter) Write(p []byte) (int, error) {
// Ensure that the current write offset matches how many bytes have been
// written to the digester. If not, we need to update the digest state to
// match the current write position.
if err := bw.resumeDigestAt(bw.blobStore.ctx, bw.offset); err != nil && err != errResumableDigestNotAvailable {
if err := bw.resumeDigest(bw.blobStore.ctx); err != nil && err != errResumableDigestNotAvailable {
return 0, err
}
n, err := io.MultiWriter(&bw.fileWriter, bw.digester.Hash()).Write(p)
n, err := io.MultiWriter(bw.fileWriter, bw.digester.Hash()).Write(p)
bw.written += int64(n)
return n, err
@ -110,21 +119,17 @@ func (bw *blobWriter) ReadFrom(r io.Reader) (n int64, err error) {
// Ensure that the current write offset matches how many bytes have been
// written to the digester. If not, we need to update the digest state to
// match the current write position.
if err := bw.resumeDigestAt(bw.blobStore.ctx, bw.offset); err != nil && err != errResumableDigestNotAvailable {
if err := bw.resumeDigest(bw.blobStore.ctx); err != nil && err != errResumableDigestNotAvailable {
return 0, err
}
nn, err := bw.fileWriter.ReadFrom(io.TeeReader(r, bw.digester.Hash()))
nn, err := io.Copy(io.MultiWriter(bw.fileWriter, bw.digester.Hash()), r)
bw.written += nn
return nn, err
}
func (bw *blobWriter) Close() error {
if bw.err != nil {
return bw.err
}
if err := bw.storeHashState(bw.blobStore.ctx); err != nil {
return err
}
@ -148,8 +153,10 @@ func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descri
}
}
var size int64
// Stat the on disk file
if fi, err := bw.fileWriter.driver.Stat(ctx, bw.path); err != nil {
if fi, err := bw.driver.Stat(ctx, bw.path); err != nil {
switch err := err.(type) {
case storagedriver.PathNotFoundError:
// NOTE(stevvooe): We really don't care if the file is
@ -165,23 +172,23 @@ func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descri
return distribution.Descriptor{}, fmt.Errorf("unexpected directory at upload location %q", bw.path)
}
bw.size = fi.Size()
size = fi.Size()
}
if desc.Size > 0 {
if desc.Size != bw.size {
if desc.Size != size {
return distribution.Descriptor{}, distribution.ErrBlobInvalidLength
}
} else {
// if provided 0 or negative length, we can assume caller doesn't know or
// care about length.
desc.Size = bw.size
desc.Size = size
}
// TODO(stevvooe): This section is very meandering. Need to be broken down
// to be a lot more clear.
if err := bw.resumeDigestAt(ctx, bw.size); err == nil {
if err := bw.resumeDigest(ctx); err == nil {
canonical = bw.digester.Digest()
if canonical.Algorithm() == desc.Digest.Algorithm() {
@ -206,7 +213,7 @@ func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descri
// the same, we don't need to read the data from the backend. This is
// because we've written the entire file in the lifecycle of the
// current instance.
if bw.written == bw.size && digest.Canonical == desc.Digest.Algorithm() {
if bw.written == size && digest.Canonical == desc.Digest.Algorithm() {
canonical = bw.digester.Digest()
verified = desc.Digest == canonical
}
@ -223,7 +230,7 @@ func (bw *blobWriter) validateBlob(ctx context.Context, desc distribution.Descri
}
// Read the file from the backend driver and validate it.
fr, err := newFileReader(ctx, bw.fileWriter.driver, bw.path, desc.Size)
fr, err := newFileReader(ctx, bw.driver, bw.path, desc.Size)
if err != nil {
return distribution.Descriptor{}, err
}
@ -357,7 +364,7 @@ func (bw *blobWriter) Reader() (io.ReadCloser, error) {
// todo(richardscothern): Change to exponential backoff, i=0.5, e=2, n=4
try := 1
for try <= 5 {
_, err := bw.fileWriter.driver.Stat(bw.ctx, bw.path)
_, err := bw.driver.Stat(bw.ctx, bw.path)
if err == nil {
break
}
@ -371,7 +378,7 @@ func (bw *blobWriter) Reader() (io.ReadCloser, error) {
}
}
readCloser, err := bw.fileWriter.driver.ReadStream(bw.ctx, bw.path, 0)
readCloser, err := bw.driver.Reader(bw.ctx, bw.path, 0)
if err != nil {
return nil, err
}