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package reference
import (
"errors"
"fmt"
"strings"
"github.com/opencontainers/go-digest"
)
var (
legacyDefaultDomain = "index.docker.io"
defaultDomain = "docker.io"
officialRepoName = "library"
defaultTag = "latest"
)
// normalizedNamed represents a name which has been
// normalized and has a familiar form. A familiar name
// is what is used in Docker UI. An example normalized
// name is "docker.io/library/ubuntu" and corresponding
// familiar name of "ubuntu".
type normalizedNamed interface {
Named
Familiar() Named
}
// ParseNormalizedNamed parses a string into a named reference
// transforming a familiar name from Docker UI to a fully
// qualified reference. If the value may be an identifier
// use ParseAnyReference.
func ParseNormalizedNamed(s string) (Named, error) {
if ok := anchoredIdentifierRegexp.MatchString(s); ok {
return nil, fmt.Errorf("invalid repository name (%s), cannot specify 64-byte hexadecimal strings", s)
}
domain, remainder := splitDockerDomain(s)
var remoteName string
if tagSep := strings.IndexRune(remainder, ':'); tagSep > -1 {
remoteName = remainder[:tagSep]
} else {
remoteName = remainder
}
if strings.ToLower(remoteName) != remoteName {
return nil, errors.New("invalid reference format: repository name must be lowercase")
}
ref, err := Parse(domain + "/" + remainder)
if err != nil {
return nil, err
}
named, isNamed := ref.(Named)
if !isNamed {
return nil, fmt.Errorf("reference %s has no name", ref.String())
}
return named, nil
}
// ParseDockerRef normalizes the image reference following the docker convention. This is added
// mainly for backward compatibility.
// The reference returned can only be either tagged or digested. For reference contains both tag
// and digest, the function returns digested reference, e.g. docker.io/library/busybox:latest@
// sha256:7cc4b5aefd1d0cadf8d97d4350462ba51c694ebca145b08d7d41b41acc8db5aa will be returned as
// docker.io/library/busybox@sha256:7cc4b5aefd1d0cadf8d97d4350462ba51c694ebca145b08d7d41b41acc8db5aa.
func ParseDockerRef(ref string) (Named, error) {
named, err := ParseNormalizedNamed(ref)
if err != nil {
return nil, err
}
if _, ok := named.(NamedTagged); ok {
if canonical, ok := named.(Canonical); ok {
// The reference is both tagged and digested, only
// return digested.
newNamed, err := WithName(canonical.Name())
if err != nil {
return nil, err
}
newCanonical, err := WithDigest(newNamed, canonical.Digest())
if err != nil {
return nil, err
}
return newCanonical, nil
}
}
return TagNameOnly(named), nil
}
// splitDockerDomain splits a repository name to domain and remotename string.
// If no valid domain is found, the default domain is used. Repository name
// needs to be already validated before.
func splitDockerDomain(name string) (domain, remainder string) {
i := strings.IndexRune(name, '/')
if i == -1 || (!strings.ContainsAny(name[:i], ".:") && name[:i] != "localhost") {
domain, remainder = defaultDomain, name
} else {
domain, remainder = name[:i], name[i+1:]
}
if domain == legacyDefaultDomain {
domain = defaultDomain
}
if domain == defaultDomain && !strings.ContainsRune(remainder, '/') {
remainder = officialRepoName + "/" + remainder
}
return
}
// familiarizeName returns a shortened version of the name familiar
// to to the Docker UI. Familiar names have the default domain
// "docker.io" and "library/" repository prefix removed.
// For example, "docker.io/library/redis" will have the familiar
// name "redis" and "docker.io/dmcgowan/myapp" will be "dmcgowan/myapp".
// Returns a familiarized named only reference.
func familiarizeName(named namedRepository) repository {
repo := repository{
domain: named.Domain(),
path: named.Path(),
}
if repo.domain == defaultDomain {
repo.domain = ""
// Handle official repositories which have the pattern "library/<official repo name>"
if split := strings.Split(repo.path, "/"); len(split) == 2 && split[0] == officialRepoName {
repo.path = split[1]
}
}
return repo
}
func (r reference) Familiar() Named {
return reference{
namedRepository: familiarizeName(r.namedRepository),
tag: r.tag,
digest: r.digest,
}
}
func (r repository) Familiar() Named {
return familiarizeName(r)
}
func (t taggedReference) Familiar() Named {
return taggedReference{
namedRepository: familiarizeName(t.namedRepository),
tag: t.tag,
}
}
func (c canonicalReference) Familiar() Named {
return canonicalReference{
namedRepository: familiarizeName(c.namedRepository),
digest: c.digest,
}
}
// TagNameOnly adds the default tag "latest" to a reference if it only has
// a repo name.
func TagNameOnly(ref Named) Named {
if IsNameOnly(ref) {
namedTagged, err := WithTag(ref, defaultTag)
if err != nil {
// Default tag must be valid, to create a NamedTagged
// type with non-validated input the WithTag function
// should be used instead
panic(err)
}
return namedTagged
}
return ref
}
// ParseAnyReference parses a reference string as a possible identifier,
// full digest, or familiar name.
func ParseAnyReference(ref string) (Reference, error) {
if ok := anchoredIdentifierRegexp.MatchString(ref); ok {
return digestReference("sha256:" + ref), nil
}
if dgst, err := digest.Parse(ref); err == nil {
return digestReference(dgst), nil
}
return ParseNormalizedNamed(ref)
}
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