distribution/docs/storage/schema2manifesthandler.go
John Starks dd66aabeba Add support for layers from foreign sources
This will be used to support downloading Windows base layers from
Microsoft URLs.

Signed-off-by: John Starks <jostarks@microsoft.com>
2016-05-20 12:31:10 -07:00

128 lines
3.6 KiB
Go

package storage
import (
"errors"
"fmt"
"net/url"
"encoding/json"
"github.com/docker/distribution"
"github.com/docker/distribution/context"
"github.com/docker/distribution/digest"
"github.com/docker/distribution/manifest/schema2"
)
var (
errUnexpectedURL = errors.New("unexpected URL on layer")
errMissingURL = errors.New("missing URL on layer")
errInvalidURL = errors.New("invalid URL on layer")
)
//schema2ManifestHandler is a ManifestHandler that covers schema2 manifests.
type schema2ManifestHandler struct {
repository *repository
blobStore *linkedBlobStore
ctx context.Context
}
var _ ManifestHandler = &schema2ManifestHandler{}
func (ms *schema2ManifestHandler) Unmarshal(ctx context.Context, dgst digest.Digest, content []byte) (distribution.Manifest, error) {
context.GetLogger(ms.ctx).Debug("(*schema2ManifestHandler).Unmarshal")
var m schema2.DeserializedManifest
if err := json.Unmarshal(content, &m); err != nil {
return nil, err
}
return &m, nil
}
func (ms *schema2ManifestHandler) Put(ctx context.Context, manifest distribution.Manifest, skipDependencyVerification bool) (digest.Digest, error) {
context.GetLogger(ms.ctx).Debug("(*schema2ManifestHandler).Put")
m, ok := manifest.(*schema2.DeserializedManifest)
if !ok {
return "", fmt.Errorf("non-schema2 manifest put to schema2ManifestHandler: %T", manifest)
}
if err := ms.verifyManifest(ms.ctx, *m, skipDependencyVerification); err != nil {
return "", err
}
mt, payload, err := m.Payload()
if err != nil {
return "", err
}
revision, err := ms.blobStore.Put(ctx, mt, payload)
if err != nil {
context.GetLogger(ctx).Errorf("error putting payload into blobstore: %v", err)
return "", err
}
// Link the revision into the repository.
if err := ms.blobStore.linkBlob(ctx, revision); err != nil {
return "", err
}
return revision.Digest, nil
}
// verifyManifest ensures that the manifest content is valid from the
// perspective of the registry. As a policy, the registry only tries to store
// valid content, leaving trust policies of that content up to consumers.
func (ms *schema2ManifestHandler) verifyManifest(ctx context.Context, mnfst schema2.DeserializedManifest, skipDependencyVerification bool) error {
var errs distribution.ErrManifestVerification
if !skipDependencyVerification {
target := mnfst.Target()
_, err := ms.repository.Blobs(ctx).Stat(ctx, target.Digest)
if err != nil {
if err != distribution.ErrBlobUnknown {
errs = append(errs, err)
}
// On error here, we always append unknown blob errors.
errs = append(errs, distribution.ErrManifestBlobUnknown{Digest: target.Digest})
}
for _, fsLayer := range mnfst.References() {
var err error
if fsLayer.MediaType != schema2.MediaTypeForeignLayer {
if len(fsLayer.URLs) == 0 {
_, err = ms.repository.Blobs(ctx).Stat(ctx, fsLayer.Digest)
} else {
err = errUnexpectedURL
}
} else {
// Clients download this layer from an external URL, so do not check for
// its presense.
if len(fsLayer.URLs) == 0 {
err = errMissingURL
}
for _, u := range fsLayer.URLs {
var pu *url.URL
pu, err = url.Parse(u)
if err != nil || (pu.Scheme != "http" && pu.Scheme != "https") || pu.Fragment != "" {
err = errInvalidURL
}
}
}
if err != nil {
if err != distribution.ErrBlobUnknown {
errs = append(errs, err)
}
// On error here, we always append unknown blob errors.
errs = append(errs, distribution.ErrManifestBlobUnknown{Digest: fsLayer.Digest})
}
}
}
if len(errs) != 0 {
return errs
}
return nil
}