containerd/services/content/writer.go
Derek McGowan 9613acb2ed
Add context to content commit
Content commit is updated to take in a context, allowing
content to be committed within the same context the writer
was in. This is useful when commit may be able to use more
context to complete the action rather than creating its own.
An example of this being useful is for the metadata implementation
of content, having a context allows tests to fully create
content in one database transaction by making use of the context.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>
2017-09-06 10:19:12 -07:00

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{}, 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(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()
}