distribution/manifest/schema1/reference_builder.go
Stephen J Day 9c88801a12
context: remove definition of Context
Back in the before time, the best practices surrounding usage of Context
weren't quite worked out. We defined our own type to make usage easier.
As this packaged was used elsewhere, it make it more and more
challenging to integrate with the forked `Context` type. Now that it is
available in the standard library, we can just use that one directly.

To make usage more consistent, we now use `dcontext` when referring to
the distribution context package.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2017-08-11 15:53:31 -07:00

99 lines
2.7 KiB
Go

package schema1
import (
"context"
"errors"
"fmt"
"github.com/docker/distribution"
"github.com/docker/distribution/manifest"
"github.com/docker/distribution/reference"
"github.com/docker/libtrust"
"github.com/opencontainers/go-digest"
)
// referenceManifestBuilder is a type for constructing manifests from schema1
// dependencies.
type referenceManifestBuilder struct {
Manifest
pk libtrust.PrivateKey
}
// NewReferenceManifestBuilder is used to build new manifests for the current
// schema version using schema1 dependencies.
func NewReferenceManifestBuilder(pk libtrust.PrivateKey, ref reference.Named, architecture string) distribution.ManifestBuilder {
tag := ""
if tagged, isTagged := ref.(reference.Tagged); isTagged {
tag = tagged.Tag()
}
return &referenceManifestBuilder{
Manifest: Manifest{
Versioned: manifest.Versioned{
SchemaVersion: 1,
},
Name: ref.Name(),
Tag: tag,
Architecture: architecture,
},
pk: pk,
}
}
func (mb *referenceManifestBuilder) Build(ctx context.Context) (distribution.Manifest, error) {
m := mb.Manifest
if len(m.FSLayers) == 0 {
return nil, errors.New("cannot build manifest with zero layers or history")
}
m.FSLayers = make([]FSLayer, len(mb.Manifest.FSLayers))
m.History = make([]History, len(mb.Manifest.History))
copy(m.FSLayers, mb.Manifest.FSLayers)
copy(m.History, mb.Manifest.History)
return Sign(&m, mb.pk)
}
// AppendReference adds a reference to the current ManifestBuilder
func (mb *referenceManifestBuilder) AppendReference(d distribution.Describable) error {
r, ok := d.(Reference)
if !ok {
return fmt.Errorf("Unable to add non-reference type to v1 builder")
}
// Entries need to be prepended
mb.Manifest.FSLayers = append([]FSLayer{{BlobSum: r.Digest}}, mb.Manifest.FSLayers...)
mb.Manifest.History = append([]History{r.History}, mb.Manifest.History...)
return nil
}
// References returns the current references added to this builder
func (mb *referenceManifestBuilder) References() []distribution.Descriptor {
refs := make([]distribution.Descriptor, len(mb.Manifest.FSLayers))
for i := range mb.Manifest.FSLayers {
layerDigest := mb.Manifest.FSLayers[i].BlobSum
history := mb.Manifest.History[i]
ref := Reference{layerDigest, 0, history}
refs[i] = ref.Descriptor()
}
return refs
}
// Reference describes a manifest v2, schema version 1 dependency.
// An FSLayer associated with a history entry.
type Reference struct {
Digest digest.Digest
Size int64 // if we know it, set it for the descriptor.
History History
}
// Descriptor describes a reference
func (r Reference) Descriptor() distribution.Descriptor {
return distribution.Descriptor{
MediaType: MediaTypeManifestLayer,
Digest: r.Digest,
Size: r.Size,
}
}