containerd/services/content/writer.go
Derek McGowan dee8dc2cda
Add support for content labels on commit
Add commit options which allow for setting labels on commit.
Prevents potential race between garbage collector reading labels
after commit and labels getting set.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>
2017-08-11 14:15:20 -07:00

123 lines
2.6 KiB
Go

package content
import (
"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{}, err
}
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(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()
}