| context | Package context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes. |
| github.com/docker/distribution | Package distribution will define the interfaces for the components of docker distribution. |
| github.com/docker/distribution/reference | Package reference is deprecated, and has moved to github.com/distribution/reference. |
| github.com/docker/distribution/registry/storage/cache | Package cache provides facilities to speed up access to the storage backend. |
| github.com/opencontainers/go-digest | Package digest provides a generalized type to opaquely represent message digests and their operations within the registry. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |