| encoding/json | Package json implements encoding and decoding of JSON as defined in RFC 7159. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/docker/distribution/reference | Package reference is deprecated, and has moved to github.com/distribution/reference. |
| github.com/docker/docker/pkg/ioutils | |
| github.com/opencontainers/go-digest | Package digest provides a generalized type to opaquely represent message digests and their operations within the registry. |
| github.com/pkg/errors | Package errors provides simple error handling primitives. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| path/filepath | Package filepath implements utility routines for manipulating filename paths in a way compatible with the target operating system-defined file paths. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| sync | Package sync provides basic synchronization primitives such as mutual exclusion locks. |