containerd/remotes/handlers.go
Derek McGowan 1cdb010783
Replace lockfile with reference lock
Updates content service to handle lock errors and return
them to the client. The client remote handler has been
updated to retry when a resource is locked until the
resource is unlocked or the expected resource exists.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>
2017-06-08 16:07:38 -07:00

120 lines
3.4 KiB
Go

package remotes
import (
"context"
"fmt"
"time"
"github.com/Sirupsen/logrus"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/images"
"github.com/containerd/containerd/log"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
)
// MakeRef returns a unique reference for the descriptor. This reference can be
// used to lookup ongoing processes related to the descriptor. This function
// may look to the context to namespace the reference appropriately.
func MakeRefKey(ctx context.Context, desc ocispec.Descriptor) string {
// TODO(stevvooe): Need better remote key selection here. Should be a
// product of the context, which may include information about the ongoing
// fetch process.
switch desc.MediaType {
case images.MediaTypeDockerSchema2Manifest, ocispec.MediaTypeImageManifest,
images.MediaTypeDockerSchema2ManifestList, ocispec.MediaTypeImageIndex:
return "manifest-" + desc.Digest.String()
case images.MediaTypeDockerSchema2Layer, images.MediaTypeDockerSchema2LayerGzip:
return "layer-" + desc.Digest.String()
case "application/vnd.docker.container.image.v1+json":
return "config-" + desc.Digest.String()
default:
log.G(ctx).Warnf("reference for unknown type: %s", desc.MediaType)
return "unknown-" + desc.Digest.String()
}
}
// FetchHandler returns a handler that will fetch all content into the ingester
// discovered in a call to Dispatch. Use with ChildrenHandler to do a full
// recursive fetch.
func FetchHandler(ingester content.Ingester, fetcher Fetcher) images.HandlerFunc {
return func(ctx context.Context, desc ocispec.Descriptor) (subdescs []ocispec.Descriptor, err error) {
ctx = log.WithLogger(ctx, log.G(ctx).WithFields(logrus.Fields{
"digest": desc.Digest,
"mediatype": desc.MediaType,
"size": desc.Size,
}))
switch desc.MediaType {
case images.MediaTypeDockerSchema2ManifestList, ocispec.MediaTypeImageIndex:
return nil, fmt.Errorf("%v not yet supported", desc.MediaType)
default:
err := fetch(ctx, ingester, fetcher, desc)
return nil, err
}
}
}
func fetch(ctx context.Context, ingester content.Ingester, fetcher Fetcher, desc ocispec.Descriptor) error {
log.G(ctx).Debug("fetch")
var (
ref = MakeRefKey(ctx, desc)
cw content.Writer
err error
retry = 16
)
for {
cw, err = ingester.Writer(ctx, ref, desc.Size, desc.Digest)
if err != nil {
if content.IsExists(err) {
return nil
} else if !content.IsLocked(err) {
return err
}
// TODO: On first time locked is encountered, get status
// of writer and abort if not updated recently.
select {
case <-time.After(time.Millisecond * time.Duration(retry)):
if retry < 2048 {
retry = retry << 1
}
continue
case <-ctx.Done():
// Propagate lock error
return err
}
}
defer cw.Close()
break
}
rc, err := fetcher.Fetch(ctx, desc)
if err != nil {
return err
}
defer rc.Close()
return content.Copy(cw, rc, desc.Size, desc.Digest)
}
func PushHandler(provider content.Provider, pusher Pusher) images.HandlerFunc {
return func(ctx context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
ctx = log.WithLogger(ctx, log.G(ctx).WithFields(logrus.Fields{
"digest": desc.Digest,
"mediatype": desc.MediaType,
"size": desc.Size,
}))
log.G(ctx).Debug("push")
r, err := provider.Reader(ctx, desc.Digest)
if err != nil {
return nil, err
}
defer r.Close()
return nil, pusher.Push(ctx, desc, r)
}
}