buildkit/util/contentutil/pusher.go

123 lines
2.5 KiB
Go

package contentutil
import (
"context"
"runtime"
"sync"
"time"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/errdefs"
"github.com/containerd/containerd/remotes"
digest "github.com/opencontainers/go-digest"
"github.com/pkg/errors"
)
func FromPusher(p remotes.Pusher) content.Ingester {
var mu sync.Mutex
c := sync.NewCond(&mu)
return &pushingIngester{
mu: &mu,
c: c,
p: p,
active: map[digest.Digest]struct{}{},
}
}
type pushingIngester struct {
p remotes.Pusher
mu *sync.Mutex
c *sync.Cond
active map[digest.Digest]struct{}
}
// Writer implements content.Ingester. desc.MediaType must be set for manifest blobs.
func (i *pushingIngester) 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
}
}
if wOpts.Ref == "" {
return nil, errors.Wrap(errdefs.ErrInvalidArgument, "ref must not be empty")
}
st := time.Now()
i.mu.Lock()
for {
if time.Since(st) > time.Hour {
i.mu.Unlock()
return nil, errors.Wrapf(errdefs.ErrUnavailable, "ref %v locked", wOpts.Desc.Digest)
}
if _, ok := i.active[wOpts.Desc.Digest]; ok {
i.c.Wait()
} else {
break
}
}
i.active[wOpts.Desc.Digest] = struct{}{}
i.mu.Unlock()
var once sync.Once
release := func() {
once.Do(func() {
i.mu.Lock()
delete(i.active, wOpts.Desc.Digest)
i.c.Broadcast()
i.mu.Unlock()
})
}
// pusher requires desc.MediaType to determine the PUT URL, especially for manifest blobs.
contentWriter, err := i.p.Push(ctx, wOpts.Desc)
if err != nil {
release()
return nil, err
}
runtime.SetFinalizer(contentWriter, func(_ content.Writer) {
release()
})
return &writer{
Writer: contentWriter,
contentWriterRef: wOpts.Ref,
release: release,
}, nil
}
type writer struct {
content.Writer // returned from pusher.Push
contentWriterRef string // ref passed for Writer()
release func()
}
func (w *writer) Status() (content.Status, error) {
st, err := w.Writer.Status()
if err != nil {
return st, err
}
if w.contentWriterRef != "" {
st.Ref = w.contentWriterRef
}
return st, nil
}
func (w *writer) Commit(ctx context.Context, size int64, expected digest.Digest, opts ...content.Opt) error {
err := w.Writer.Commit(ctx, size, expected, opts...)
if w.release != nil {
w.release()
}
return err
}
func (w *writer) Close() error {
err := w.Writer.Close()
if w.release != nil {
w.release()
}
return err
}