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moby--moby/reference/reference.go

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package reference
import (
"fmt"
"strings"
"github.com/docker/distribution/digest"
distreference "github.com/docker/distribution/reference"
"github.com/docker/docker/image/v1"
)
const (
// DefaultTag defines the default tag used when performing images related actions and no tag or digest is specified
DefaultTag = "latest"
// DefaultHostname is the default built-in hostname
DefaultHostname = "docker.io"
// LegacyDefaultHostname is automatically converted to DefaultHostname
LegacyDefaultHostname = "index.docker.io"
// DefaultRepoPrefix is the prefix used for default repositories in default host
DefaultRepoPrefix = "library/"
)
// Named is an object with a full name
type Named interface {
// Name returns normalized repository name, like "ubuntu".
Name() string
// String returns full reference, like "ubuntu@sha256:abcdef..."
String() string
// FullName returns full repository name with hostname, like "docker.io/library/ubuntu"
FullName() string
// Hostname returns hostname for the reference, like "docker.io"
Hostname() string
// RemoteName returns the repository component of the full name, like "library/ubuntu"
RemoteName() string
}
// NamedTagged is an object including a name and tag.
type NamedTagged interface {
Named
Tag() string
}
// Canonical reference is an object with a fully unique
// name including a name with hostname and digest
type Canonical interface {
Named
Digest() digest.Digest
}
// ParseNamed parses s and returns a syntactically valid reference implementing
// the Named interface. The reference must have a name, otherwise an error is
// returned.
// If an error was encountered it is returned, along with a nil Reference.
func ParseNamed(s string) (Named, error) {
named, err := distreference.ParseNamed(s)
if err != nil {
return nil, fmt.Errorf("Error parsing reference: %q is not a valid repository/tag", s)
}
r, err := WithName(named.Name())
if err != nil {
return nil, err
}
if canonical, isCanonical := named.(distreference.Canonical); isCanonical {
return WithDigest(r, canonical.Digest())
}
if tagged, isTagged := named.(distreference.NamedTagged); isTagged {
return WithTag(r, tagged.Tag())
}
return r, nil
}
// WithName returns a named object representing the given string. If the input
// is invalid ErrReferenceInvalidFormat will be returned.
func WithName(name string) (Named, error) {
name = normalize(name)
if err := validateName(name); err != nil {
return nil, err
}
r, err := distreference.WithName(name)
if err != nil {
return nil, err
}
return &namedRef{r}, nil
}
// WithTag combines the name from "name" and the tag from "tag" to form a
// reference incorporating both the name and the tag.
func WithTag(name Named, tag string) (NamedTagged, error) {
r, err := distreference.WithTag(name, tag)
if err != nil {
return nil, err
}
return &taggedRef{namedRef{r}}, nil
}
// WithDigest combines the name from "name" and the digest from "digest" to form
// a reference incorporating both the name and the digest.
func WithDigest(name Named, digest digest.Digest) (Canonical, error) {
r, err := distreference.WithDigest(name, digest)
if err != nil {
return nil, err
}
return &canonicalRef{namedRef{r}}, nil
}
type namedRef struct {
distreference.Named
}
type taggedRef struct {
namedRef
}
type canonicalRef struct {
namedRef
}
func (r *namedRef) FullName() string {
hostname, remoteName := splitHostname(r.Name())
return hostname + "/" + remoteName
}
func (r *namedRef) Hostname() string {
hostname, _ := splitHostname(r.Name())
return hostname
}
func (r *namedRef) RemoteName() string {
_, remoteName := splitHostname(r.Name())
return remoteName
}
func (r *taggedRef) Tag() string {
return r.namedRef.Named.(distreference.NamedTagged).Tag()
}
func (r *canonicalRef) Digest() digest.Digest {
return r.namedRef.Named.(distreference.Canonical).Digest()
}
// WithDefaultTag adds a default tag to a reference if it only has a repo name.
func WithDefaultTag(ref Named) Named {
if IsNameOnly(ref) {
ref, _ = WithTag(ref, DefaultTag)
}
return ref
}
// IsNameOnly returns true if reference only contains a repo name.
func IsNameOnly(ref Named) bool {
if _, ok := ref.(NamedTagged); ok {
return false
}
if _, ok := ref.(Canonical); ok {
return false
}
return true
}
// splitHostname splits a repository name to hostname and remotename string.
// If no valid hostname is found, the default hostname is used. Repository name
// needs to be already validated before.
func splitHostname(name string) (hostname, remoteName string) {
i := strings.IndexRune(name, '/')
if i == -1 || (!strings.ContainsAny(name[:i], ".:") && name[:i] != "localhost") {
hostname, remoteName = DefaultHostname, name
} else {
hostname, remoteName = name[:i], name[i+1:]
}
if hostname == LegacyDefaultHostname {
hostname = DefaultHostname
}
if hostname == DefaultHostname && !strings.ContainsRune(remoteName, '/') {
remoteName = DefaultRepoPrefix + remoteName
}
return
}
// normalize returns a repository name in its normalized form, meaning it
// will not contain default hostname nor library/ prefix for official images.
func normalize(name string) string {
host, remoteName := splitHostname(name)
if host == DefaultHostname {
if strings.HasPrefix(remoteName, DefaultRepoPrefix) {
return strings.TrimPrefix(remoteName, DefaultRepoPrefix)
}
return remoteName
}
return name
}
func validateName(name string) error {
if err := v1.ValidateID(name); err == nil {
return fmt.Errorf("Invalid repository name (%s), cannot specify 64-byte hexadecimal strings", name)
}
return nil
}