distribution/manifests.go
Richard Scothern cb6f002350 Implementation of the Manifest Service API refactor.
Add a generic Manifest interface to represent manifests in the registry and
remove references to schema specific manifests.

Add a ManifestBuilder to construct Manifest objects. Concrete manifest builders
will exist for each manifest type and implementations will contain manifest
specific data used to build a manifest.

Remove Signatures() from Repository interface.

Signatures are relevant only to schema1 manifests.  Move access to the signature
store inside the schema1 manifestStore.  Add some API tests to verify
signature roundtripping.

schema1
-------

Change the way data is stored in schema1.Manifest to enable Payload() to be used
to return complete Manifest JSON from the HTTP handler without knowledge of the
schema1 protocol.

tags
----

Move tag functionality to a seperate TagService and update ManifestService
to use the new interfaces.  Implement a driver based tagService to be backward
compatible with the current tag service.

Add a proxyTagService to enable the registry to get a digest for remote manifests
from a tag.

manifest store
--------------

Remove revision store and move all signing functionality into the signed manifeststore.

manifest registration
---------------------

Add a mechanism to register manifest media types and to allow different manifest
types to be Unmarshalled correctly.

client
------

Add ManifestServiceOptions to client functions to allow tags to be passed into Put and
Get for building correct registry URLs.  Change functional arguments to be an interface type
to allow passing data without mutating shared state.

Signed-off-by: Richard Scothern <richard.scothern@gmail.com>

Signed-off-by: Richard Scothern <richard.scothern@docker.com>
2015-12-17 17:09:14 -08:00

100 lines
3.6 KiB
Go

package distribution
import (
"fmt"
"github.com/docker/distribution/context"
"github.com/docker/distribution/digest"
)
// Manifest represents a registry object specifying a set of
// references and an optional target
type Manifest interface {
// References returns a list of objects which make up this manifest.
// The references are strictly ordered from base to head. A reference
// is anything which can be represented by a distribution.Descriptor
References() []Descriptor
// Payload provides the serialized format of the manifest, in addition to
// the mediatype.
Payload() (mediatype string, payload []byte, err error)
}
// ManifestBuilder creates a manifest allowing one to include dependencies.
// Instances can be obtained from a version-specific manifest package. Manifest
// specific data is passed into the function which creates the builder.
type ManifestBuilder interface {
// Build creates the manifest from his builder.
Build() (Manifest, error)
// References returns a list of objects which have been added to this
// builder. The dependencies are returned in the order they were added,
// which should be from base to head.
References() []Descriptor
// AppendReference includes the given object in the manifest after any
// existing dependencies. If the add fails, such as when adding an
// unsupported dependency, an error may be returned.
AppendReference(dependency Describable) error
}
// ManifestService describes operations on image manifests.
type ManifestService interface {
// Exists returns true if the manifest exists.
Exists(ctx context.Context, dgst digest.Digest) (bool, error)
// Get retrieves the manifest specified by the given digest
Get(ctx context.Context, dgst digest.Digest, options ...ManifestServiceOption) (Manifest, error)
// Put creates or updates the given manifest returning the manifest digest
Put(ctx context.Context, manifest Manifest, options ...ManifestServiceOption) (digest.Digest, error)
// Delete removes the manifest specified by the given digest. Deleting
// a manifest that doesn't exist will return ErrManifestNotFound
Delete(ctx context.Context, dgst digest.Digest) error
// Enumerate fills 'manifests' with the manifests in this service up
// to the size of 'manifests' and returns 'n' for the number of entries
// which were filled. 'last' contains an offset in the manifest set
// and can be used to resume iteration.
//Enumerate(ctx context.Context, manifests []Manifest, last Manifest) (n int, err error)
}
// Describable is an interface for descriptors
type Describable interface {
Descriptor() Descriptor
}
// ManifestMediaTypes returns the supported media types for manifests.
func ManifestMediaTypes() (mediaTypes []string) {
for t := range mappings {
mediaTypes = append(mediaTypes, t)
}
return
}
// UnmarshalFunc implements manifest unmarshalling a given MediaType
type UnmarshalFunc func([]byte) (Manifest, Descriptor, error)
var mappings = make(map[string]UnmarshalFunc, 0)
// UnmarshalManifest looks up manifest unmarshall functions based on
// MediaType
func UnmarshalManifest(mediatype string, p []byte) (Manifest, Descriptor, error) {
unmarshalFunc, ok := mappings[mediatype]
if !ok {
return nil, Descriptor{}, fmt.Errorf("unsupported manifest mediatype: %s", mediatype)
}
return unmarshalFunc(p)
}
// RegisterManifestSchema registers an UnmarshalFunc for a given schema type. This
// should be called from specific
func RegisterManifestSchema(mediatype string, u UnmarshalFunc) error {
if _, ok := mappings[mediatype]; ok {
return fmt.Errorf("manifest mediatype registration would overwrite existing: %s", mediatype)
}
mappings[mediatype] = u
return nil
}