ManifestHandler expends the ability of handling manifest list in schema2, but it's not finished yet return the digest array of manifests in the manifest list if exist.

NewImageDestination generates a ImageDestination by repository, the repository string must include "tag".

NewImageSource generates a PullTask by repository, the repository string must include "tag", if username or password is empty, access to repository will be anonymous.

NewTask creates a sync task.

NoCache used to disable a blobinfocache.

ImageDestination is a reference of a remote image we will push to.

ImageSource is a reference to a remote image need to be pulled.

Task act as a sync action, it will pull a images from source to destination.