distribution/manifest/schema2/builder.go
Aaron Lehmann 2ff77c00ba Add schema2 manifest support
Add schema2 manifest implementation.

Add a schema2 builder that creates a schema2 manifest from descriptors
and a configuration. It will add the configuration to the blob store if
necessary.

Rename the original schema1 manifest builder to ReferenceBuilder, and
create a ConfigBuilder variant that can build a schema1 manifest from an
image configuration and set of descriptors. This will be used to
translate schema2 manifests to the schema1 format for backward
compatibliity, by adding the descriptors from the existing schema2
manifest to the schema1 builder. It will also be used by engine-side
push code to create schema1 manifests from the new-style image
configration, when necessary to push a schema1 manifest.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2016-01-07 15:26:26 -08:00

79 lines
2.0 KiB
Go

package schema2
import (
"github.com/docker/distribution"
"github.com/docker/distribution/context"
"github.com/docker/distribution/digest"
"github.com/docker/distribution/manifest"
)
// builder is a type for constructing manifests.
type builder struct {
// bs is a BlobService used to publish the configuration blob.
bs distribution.BlobService
// configJSON references
configJSON []byte
// layers is a list of layer descriptors that gets built by successive
// calls to AppendReference.
layers []distribution.Descriptor
}
// NewManifestBuilder is used to build new manifests for the current schema
// version. It takes a BlobService so it can publish the configuration blob
// as part of the Build process.
func NewManifestBuilder(bs distribution.BlobService, configJSON []byte) distribution.ManifestBuilder {
mb := &builder{
bs: bs,
configJSON: make([]byte, len(configJSON)),
}
copy(mb.configJSON, configJSON)
return mb
}
// Build produces a final manifest from the given references.
func (mb *builder) Build(ctx context.Context) (distribution.Manifest, error) {
m := Manifest{
Versioned: manifest.Versioned{
SchemaVersion: 2,
},
MediaType: MediaTypeManifest,
Layers: make([]distribution.Descriptor, len(mb.layers)),
}
copy(m.Layers, mb.layers)
configDigest := digest.FromBytes(mb.configJSON)
var err error
m.Config, err = mb.bs.Stat(ctx, configDigest)
switch err {
case nil:
return FromStruct(m)
case distribution.ErrBlobUnknown:
// nop
default:
return nil, err
}
// Add config to the blob store
m.Config, err = mb.bs.Put(ctx, MediaTypeConfig, mb.configJSON)
if err != nil {
return nil, err
}
return FromStruct(m)
}
// AppendReference adds a reference to the current ManifestBuilder.
func (mb *builder) AppendReference(d distribution.Describable) error {
mb.layers = append(mb.layers, d.Descriptor())
return nil
}
// References returns the current references added to this builder.
func (mb *builder) References() []distribution.Descriptor {
return mb.layers
}