Files
containerd/services/content/writer.go
Stephen J Day 3e5e2ecc0a content/local: consistent handling of data and locks
The locks now retry on the backend side to prevent clients from having
to round trip on locks that might be momentarily held. This exposed some
timing errors in the updated_at fields for content ingest, so we've had
to move that to a separate file to export the monotonic go runtime
timestamps.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2017-11-16 16:13:19 -05:00

124 lines
2.6 KiB
Go

package content
import (
"context"
"io"
contentapi "github.com/containerd/containerd/api/services/content/v1"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/errdefs"
digest "github.com/opencontainers/go-digest"
"github.com/pkg/errors"
)
type remoteWriter struct {
ref string
client contentapi.Content_WriteClient
offset int64
digest digest.Digest
}
// send performs a synchronous req-resp cycle on the client.
func (rw *remoteWriter) send(req *contentapi.WriteContentRequest) (*contentapi.WriteContentResponse, error) {
if err := rw.client.Send(req); err != nil {
return nil, err
}
resp, err := rw.client.Recv()
if err == nil {
// try to keep these in sync
if resp.Digest != "" {
rw.digest = resp.Digest
}
}
return resp, err
}
func (rw *remoteWriter) Status() (content.Status, error) {
resp, err := rw.send(&contentapi.WriteContentRequest{
Action: contentapi.WriteActionStat,
})
if err != nil {
return content.Status{}, errors.Wrap(err, "error getting writer status")
}
return content.Status{
Ref: rw.ref,
Offset: resp.Offset,
Total: resp.Total,
StartedAt: resp.StartedAt,
UpdatedAt: resp.UpdatedAt,
}, nil
}
func (rw *remoteWriter) Digest() digest.Digest {
return rw.digest
}
func (rw *remoteWriter) Write(p []byte) (n int, err error) {
offset := rw.offset
resp, err := rw.send(&contentapi.WriteContentRequest{
Action: contentapi.WriteActionWrite,
Offset: offset,
Data: p,
})
if err != nil {
return 0, err
}
n = int(resp.Offset - offset)
if n < len(p) {
err = io.ErrShortWrite
}
rw.offset += int64(n)
if resp.Digest != "" {
rw.digest = resp.Digest
}
return
}
func (rw *remoteWriter) Commit(ctx context.Context, size int64, expected digest.Digest, opts ...content.Opt) error {
var base content.Info
for _, opt := range opts {
if err := opt(&base); err != nil {
return err
}
}
resp, err := rw.send(&contentapi.WriteContentRequest{
Action: contentapi.WriteActionCommit,
Total: size,
Offset: rw.offset,
Expected: expected,
Labels: base.Labels,
})
if err != nil {
return errdefs.FromGRPC(err)
}
if size != 0 && resp.Offset != size {
return errors.Errorf("unexpected size: %v != %v", resp.Offset, size)
}
if expected != "" && resp.Digest != expected {
return errors.Errorf("unexpected digest: %v != %v", resp.Digest, expected)
}
rw.digest = resp.Digest
rw.offset = resp.Offset
return nil
}
func (rw *remoteWriter) Truncate(size int64) error {
// This truncation won't actually be validated until a write is issued.
rw.offset = size
return nil
}
func (rw *remoteWriter) Close() error {
return rw.client.CloseSend()
}