Add a new reference package abstracting repositories, tags and digests

There seems to be a need for a type that represents a way of pointing
to an image, irrespective of the implementation.

This patch defines a Reference interface and provides 3 implementations:
- TagReference: when only a tag is provided
- DigestReference: when a digest (according to the digest package) is
  provided, can include optional tag as well

Validation of references are purely syntactic.

There is also a strong type for tags, analogous to digests, as well
as a strong type for Repository from which clients can access the
hostname alone, or the repository name without the hostname, or both
together via the String() method.

For Repository, the files names.go and names_test.go were moved from
the v2 package.

Signed-off-by: Tibor Vass <tibor@docker.com>

reference/reference.go

@@ -0,0 +1,186 @@
+// Package reference provides a general type to represent any way of referencing images within the registry.
+// Its main purpose is to abstract tags and digests (content-addressable hash).
+//
+// Grammar
+//
+// 	reference                       := repository [ ":" tag ] [ "@" digest ]
+//
+//	// repository.go
+//	repository			:= hostname ['/' component]+
+//	hostname 			:= component [':' port-number]
+//	component			:= alpha-numeric [separator alpha-numeric]*
+// 	alpha-numeric			:= /[a-zA-Z0-9]+/
+//	separator			:= /[._-]/
+//	port-number			:= /[0-9]+/
+//
+//	// tag.go
+//	tag                             := /[\w][\w.-]{0,127}/
+//
+//	// from the digest package
+//	digest                          := digest-algorithm ":" digest-hex
+//	digest-algorithm                := digest-algorithm-component [ digest-algorithm-separator digest-algorithm-component ]
+//	digest-algorithm-separator      := /[+.-_]/
+//	digest-algorithm-component      := /[A-Za-z]/ /[A-Za-z0-9]*/
+//	digest-hex                      := /[A-Za-z0-9_-]+/ ; supports hex bytes or url safe base64
+package reference
+
+import (
+	"errors"
+	"regexp"
+
+	"github.com/docker/distribution/digest"
+)
+
+// ErrReferenceInvalidFormat represents an error while trying to parse a string as a reference.
+var ErrReferenceInvalidFormat = errors.New("invalid reference format")
+
+// Reference abstracts types that reference images in a certain way.
+type Reference interface {
+	// Repository returns the repository part of a reference
+	Repository() Repository
+	// String returns the entire reference, including the repository part
+	String() string
+}
+
+func parseHostname(s string) (hostname, tail string) {
+	tail = s
+	i := regexp.MustCompile(`^` + RepositoryNameHostnameRegexp.String()).FindStringIndex(s)
+	if i == nil {
+		return
+	}
+	return s[:i[1]], s[i[1]:]
+}
+
+func parseRepositoryName(s string) (repo, tail string) {
+	tail = s
+	i := regexp.MustCompile(`^/(?:` + RepositoryNameComponentRegexp.String() + `/)*` + RepositoryNameComponentRegexp.String()).FindStringIndex(s)
+	if i == nil {
+		return
+	}
+	return s[:i[1]], s[i[1]:]
+}
+
+func parseTag(s string) (tag Tag, tail string) {
+	tail = s
+	if len(s) == 0 || s[0] != ':' {
+		return
+	}
+	tag, err := NewTag(s[1:])
+	if err != nil {
+		return
+	}
+	tail = s[len(tag)+1:]
+	return
+}
+
+func parseDigest(s string) (dgst digest.Digest, tail string) {
+	tail = s
+	if len(s) == 0 || s[0] != '@' {
+		return
+	}
+	dgst, err := digest.ParseDigest(s[1:])
+	if err != nil {
+		return
+	}
+	tail = s[len(dgst)+1:]
+	return
+}
+
+// Parse parses s and returns a syntactically valid Reference.
+// If an error was encountered it is returned, along with a nil Reference.
+func Parse(s string) (Reference, error) {
+	hostname, s := parseHostname(s)
+	name, s := parseRepositoryName(s)
+	repository := Repository{Hostname: hostname, Name: name}
+	if err := repository.Validate(); err != nil {
+		return nil, err
+	}
+	tag, s := parseTag(s)
+	dgst, s := parseDigest(s)
+	if len(s) > 0 {
+		return nil, ErrReferenceInvalidFormat
+	}
+
+	if dgst != "" {
+		return DigestReference{repository: repository, digest: dgst, tag: tag}, nil
+	}
+	if tag != "" {
+		return TagReference{repository: repository, tag: tag}, nil
+	}
+	return nil, ErrReferenceInvalidFormat
+}
+
+// DigestReference represents a reference of the form `repository@sha256:deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef`.
+// Implements the Reference interface.
+type DigestReference struct {
+	repository Repository
+	digest     digest.Digest
+	tag        Tag
+}
+
+// Repository returns the repository part.
+func (r DigestReference) Repository() Repository { return r.repository }
+
+// String returns the full string reference.
+func (r DigestReference) String() string {
+	return r.repository.String() + "@" + string(r.digest)
+}
+
+// NewDigestReference returns an initialized DigestReference.
+func NewDigestReference(canonicalRepository string, digest digest.Digest, optionalTag Tag) (DigestReference, error) {
+	ref := DigestReference{}
+
+	repo, err := NewRepository(canonicalRepository)
+	if err != nil {
+		return ref, err
+	}
+	ref.repository = repo
+
+	if err := digest.Validate(); err != nil {
+		return ref, err
+	}
+	ref.digest = digest
+
+	if len(optionalTag) > 0 {
+		if err := optionalTag.Validate(); err != nil {
+			return ref, err
+		}
+		ref.tag = optionalTag
+	}
+
+	return ref, err
+}
+
+// TagReference represents a reference of the form `repository:tag`.
+// Implements the Reference interface.
+type TagReference struct {
+	repository Repository
+	tag        Tag
+}
+
+// Repository returns the repository part.
+func (r TagReference) Repository() Repository { return r.repository }
+
+// String returns the full string reference.
+func (r TagReference) String() string {
+	return r.repository.String() + ":" + string(r.tag)
+}
+
+// NewTagReference returns an initialized TagReference.
+func NewTagReference(canonicalRepository string, tagName string) (TagReference, error) {
+	ref := TagReference{}
+
+	repo, err := NewRepository(canonicalRepository)
+	if err != nil {
+		return ref, err
+	}
+	ref.repository = repo
+
+	tag, err := NewTag(tagName)
+	if err != nil {
+		return ref, err
+	}
+	ref.tag = tag
+
+	return ref, err
+}

reference/reference_test.go

@@ -0,0 +1,56 @@
+package reference
+
+/*
+var refRegex = regexp.MustCompile(`^([a-z0-9]+(?:[-._][a-z0-9]+)*(?::[0-9]+(?:/[a-z0-9]+(?:[-._][a-z0-9]+)*)+|(?:/[a-z0-9]+(?:[-._][a-z0-9]+)*)+)?)(:[\w][\w.-]{0,127})?(@` + digest.DigestRegexp.String() + `)?$`)
+
+func getRepo(s string) string {
+	matches := refRegex.FindStringSubmatch(s)
+	if len(matches) == 0 {
+		return ""
+	}
+	return matches[1]
+}
+
+func testRepository(prefix string) error {
+	for _, s := range []string{
+		prefix + `@sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff`,
+		prefix + `:frozen@sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff`,
+		prefix + `:latest`,
+		prefix,
+	} {
+		expected := getRepo(s)
+		ref, err := Parse(s)
+		if err != nil {
+			if expected == "" {
+				continue
+			}
+			return err
+		}
+		if repo := ref.Repository(); repo.String() != expected {
+			return fmt.Errorf("repository string: expected %q, got: %q", expected, repo)
+		}
+		if refStr := ref.String(); refStr != s {
+			return fmt.Errorf("reference string: expected %q, got: %q", s, refStr)
+		}
+	}
+	return nil
+}
+
+func TestSimpleRepository(t *testing.T) {
+	if err := testRepository(`busybox`); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestUrlRepository(t *testing.T) {
+	if err := testRepository(`docker.io/library/busybox`); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestPort(t *testing.T) {
+	if err := testRepository(`busybox:1234`); err != nil {
+		t.Fatal(err)
+	}
+}
+*/

reference/repository.go

@@ -0,0 +1,136 @@
+package reference
+
+import (
+	"errors"
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+const (
+	// RepositoryNameTotalLengthMax is the maximum total number of characters in a repository name.
+	RepositoryNameTotalLengthMax = 255
+)
+
+// RepositoryNameComponentRegexp restricts registry path component names to
+// start with at least one letter or number, with following parts able to
+// be separated by one period, dash or underscore.
+var RepositoryNameComponentRegexp = regexp.MustCompile(`[a-zA-Z0-9]+(?:[._-][a-z0-9]+)*`)
+
+// RepositoryNameComponentAnchoredRegexp is the version of
+// RepositoryNameComponentRegexp which must completely match the content
+var RepositoryNameComponentAnchoredRegexp = regexp.MustCompile(`^` + RepositoryNameComponentRegexp.String() + `$`)
+
+// RepositoryNameHostnameRegexp restricts the registry hostname component of a repository name to
+// start with a component as defined by RepositoryNameComponentRegexp and followed by an optional port.
+var RepositoryNameHostnameRegexp = regexp.MustCompile(RepositoryNameComponentRegexp.String() + `(?::[0-9]+)?`)
+
+// RepositoryNameHostnameAnchoredRegexp is the version of
+// RepositoryNameHostnameRegexp which must completely match the content.
+var RepositoryNameHostnameAnchoredRegexp = regexp.MustCompile(`^` + RepositoryNameHostnameRegexp.String() + `$`)
+
+// RepositoryNameRegexp builds on RepositoryNameComponentRegexp to allow
+// multiple path components, separated by a forward slash.
+var RepositoryNameRegexp = regexp.MustCompile(`(?:` + RepositoryNameHostnameRegexp.String() + `/)?(?:` + RepositoryNameComponentRegexp.String() + `/)*` + RepositoryNameComponentRegexp.String())
+
+var (
+	// ErrRepositoryNameEmpty is returned for empty, invalid repository names.
+	ErrRepositoryNameEmpty = errors.New("repository name must have at least one component")
+
+	// ErrRepositoryNameMissingHostname is returned when a repository name
+	// does not start with a hostname
+	ErrRepositoryNameMissingHostname = errors.New("repository name must start with a hostname")
+
+	// ErrRepositoryNameHostnameInvalid is returned when a repository name
+	// does not match RepositoryNameHostnameRegexp
+	ErrRepositoryNameHostnameInvalid = fmt.Errorf("repository name must match %q", RepositoryNameHostnameRegexp.String())
+
+	// ErrRepositoryNameLong is returned when a repository name is longer than
+	// RepositoryNameTotalLengthMax
+	ErrRepositoryNameLong = fmt.Errorf("repository name must not be more than %v characters", RepositoryNameTotalLengthMax)
+
+	// ErrRepositoryNameComponentInvalid is returned when a repository name does
+	// not match RepositoryNameComponentRegexp
+	ErrRepositoryNameComponentInvalid = fmt.Errorf("repository name component must match %q", RepositoryNameComponentRegexp.String())
+)
+
+// Repository represents a reference to a Repository.
+type Repository struct {
+	// Hostname refers to the registry hostname where the repository resides.
+	Hostname string
+	// Name is a slash (`/`) separated list of string components.
+	Name string
+}
+
+// String returns the string representation of a repository.
+func (r Repository) String() string {
+	// Hostname is not supposed to be empty, but let's be nice.
+	if len(r.Hostname) == 0 {
+		return r.Name
+	}
+	return r.Hostname + "/" + r.Name
+}
+
+// Validate ensures the repository name is valid for use in the
+// registry. This function accepts a superset of what might be accepted by
+// docker core or docker hub. If the name does not pass validation, an error,
+// describing the conditions, is returned.
+//
+// Effectively, the name should comply with the following grammar:
+//
+//	repository			:= hostname ['/' component]+
+//	hostname 			:= component [':' port-number]
+//	component			:= alpha-numeric [separator alpha-numeric]*
+// 	alpha-numeric			:= /[a-zA-Z0-9]+/
+//	separator			:= /[._-]/
+//	port-number			:= /[0-9]+/
+//
+// The result of the production should be limited to 255 characters.
+func (r Repository) Validate() error {
+	n := len(r.String())
+	switch {
+	case n == 0:
+		return ErrRepositoryNameEmpty
+	case n > RepositoryNameTotalLengthMax:
+		return ErrRepositoryNameLong
+	case len(r.Hostname) <= 0:
+		return ErrRepositoryNameMissingHostname
+	case !RepositoryNameHostnameAnchoredRegexp.MatchString(r.Hostname):
+		return ErrRepositoryNameHostnameInvalid
+	}
+
+	components := r.Name
+	for {
+		var component string
+		sep := strings.Index(components, "/")
+		if sep >= 0 {
+			component = components[:sep]
+			components = components[sep+1:]
+		} else { // if no more slashes
+			component = components
+			components = ""
+		}
+		if !RepositoryNameComponentAnchoredRegexp.MatchString(component) {
+			return ErrRepositoryNameComponentInvalid
+		}
+		if sep < 0 {
+			return nil
+		}
+	}
+}
+
+// NewRepository returns a valid Repository from an input string representing
+// the canonical form of a repository name.
+// If the validation fails, an error is returned.
+func NewRepository(canonicalName string) (repo Repository, err error) {
+	if len(canonicalName) == 0 {
+		return repo, ErrRepositoryNameEmpty
+	}
+	i := strings.Index(canonicalName, "/")
+	if i <= 0 {
+		return repo, ErrRepositoryNameMissingHostname
+	}
+	repo.Hostname = canonicalName[:i]
+	repo.Name = canonicalName[i+1:]
+	return repo, repo.Validate()
+}

reference/repository_test.go

@@ -1,6 +1,7 @@
-package v2
+package reference
 
 import (
+	"regexp"
 	"strconv"
 	"strings"
 	"testing"
@@ -20,11 +21,13 @@ var (
 		invalid bool
 	}{
 		{
-			input: "",
+			input:   "",
-			err:   ErrRepositoryNameEmpty,
+			err:     ErrRepositoryNameEmpty,
+			invalid: true,
 		},
 		{
 			input: "short",
+			err:   ErrRepositoryNameMissingHostname,
 		},
 		{
 			input: "simple/name",
@@ -56,6 +59,7 @@ var (
 		},
 		{
 			input: "a",
+			err:   ErrRepositoryNameMissingHostname,
 		},
 		{
 			input: "a/aa",
@@ -72,11 +76,7 @@ var (
 			invalid: true,
 		},
 		{
-			// TODO: this testcase should be valid once we switch to
+			input: "foo.com:8080/bar",
-			// the reference package.
-			input:   "foo.com:8080/bar",
-			err:     ErrRepositoryNameComponentInvalid,
-			invalid: true,
 		},
 		{
 			input: "foo.com/bar",
@@ -92,10 +92,16 @@ var (
 		},
 		{
 			input: "asdf",
+			err:   ErrRepositoryNameMissingHostname,
+		},
+		{
+			input:   "aa/asdf$$^/aa",
+			err:     ErrRepositoryNameComponentInvalid,
+			invalid: true,
 		},
 		{
 			input:   "asdf$$^/aa",
-			err:     ErrRepositoryNameComponentInvalid,
+			err:     ErrRepositoryNameHostnameInvalid,
 			invalid: true,
 		},
 		{
@@ -107,21 +113,35 @@ var (
 		{
 			input: "a-a/a-a",
 		},
+		{
+			input: "a",
+			err:   ErrRepositoryNameMissingHostname,
+		},
+		{
+			input: "a/image",
+		},
 		{
 			input:   "a-/a/a/a",
+			err:     ErrRepositoryNameHostnameInvalid,
+			invalid: true,
+		},
+		{
+			input:   "a/a-/a/a/a",
 			err:     ErrRepositoryNameComponentInvalid,
 			invalid: true,
 		},
 		{
-			input: strings.Repeat("a", 255),
+			// total length = 255
+			input: "a/" + strings.Repeat("a", 253),
 		},
 		{
-			input: strings.Repeat("a", 256),
+			// total length = 256
+			input: "b/" + strings.Repeat("a", 254),
 			err:   ErrRepositoryNameLong,
 		},
 		{
 			input:   "-foo/bar",
-			err:     ErrRepositoryNameComponentInvalid,
+			err:     ErrRepositoryNameHostnameInvalid,
 			invalid: true,
 		},
 		{
@@ -131,7 +151,7 @@ var (
 		},
 		{
 			input:   "foo-/bar",
-			err:     ErrRepositoryNameComponentInvalid,
+			err:     ErrRepositoryNameHostnameInvalid,
 			invalid: true,
 		},
 		{
@@ -141,7 +161,7 @@ var (
 		},
 		{
 			input:   "_foo/bar",
-			err:     ErrRepositoryNameComponentInvalid,
+			err:     ErrRepositoryNameHostnameInvalid,
 			invalid: true,
 		},
 		{
@@ -151,17 +171,17 @@ var (
 		},
 		{
 			input:   "____/____",
-			err:     ErrRepositoryNameComponentInvalid,
+			err:     ErrRepositoryNameHostnameInvalid,
 			invalid: true,
 		},
 		{
 			input:   "_docker/_docker",
-			err:     ErrRepositoryNameComponentInvalid,
+			err:     ErrRepositoryNameHostnameInvalid,
 			invalid: true,
 		},
 		{
 			input:   "docker_/docker_",
-			err:     ErrRepositoryNameComponentInvalid,
+			err:     ErrRepositoryNameHostnameInvalid,
 			invalid: true,
 		},
 		{
@@ -190,8 +210,17 @@ var (
 			invalid: true,
 		},
 		{
-			input:   "-docker/docker",
+			input: "-docker/docker",
-			err:     ErrRepositoryNameComponentInvalid,
+			err:   ErrRepositoryNameComponentInvalid,
+		},
+		{
+			input:   "xn--n3h.com/myimage", // http://☃.com in punycode
+			err:     ErrRepositoryNameHostnameInvalid,
+			invalid: true,
+		},
+		{
+			input:   "xn--7o8h.com/myimage", // http://🐳.com in punycode
+			err:     ErrRepositoryNameHostnameInvalid,
 			invalid: true,
 		},
 		{
@@ -218,7 +247,7 @@ func TestValidateRepositoryName(t *testing.T) {
 			t.Fail()
 		}
 
-		if err := ValidateRepositoryName(testcase.input); err != testcase.err {
+		if _, err := NewRepository(testcase.input); err != testcase.err {
 			if testcase.err != nil {
 				if err != nil {
 					failf("unexpected error for invalid repository: got %v, expected %v", err, testcase.err)
@@ -238,13 +267,14 @@ func TestValidateRepositoryName(t *testing.T) {
 }
 
 func TestRepositoryNameRegexp(t *testing.T) {
+	AnchoredRepositoryNameRegexp := regexp.MustCompile(`^` + RepositoryNameRegexp.String() + `$`)
 	for _, testcase := range regexpTestcases {
 		failf := func(format string, v ...interface{}) {
 			t.Logf(strconv.Quote(testcase.input)+": "+format, v...)
 			t.Fail()
 		}
 
-		matches := RepositoryNameRegexp.FindString(testcase.input) == testcase.input
+		matches := AnchoredRepositoryNameRegexp.MatchString(testcase.input)
 		if matches == testcase.invalid {
 			if testcase.invalid {
 				failf("expected invalid repository name %s", testcase.input)

reference/tag.go

@@ -0,0 +1,38 @@
+package reference
+
+import (
+	"fmt"
+	"regexp"
+)
+
+var (
+	// TagRegexp matches valid tag names. From docker/docker:graph/tags.go.
+	TagRegexp = regexp.MustCompile(`[\w][\w.-]{0,127}`)
+
+	// TagAnchoredRegexp matches valid tag names, anchored at the start and
+	// end of the matched string.
+	TagAnchoredRegexp = regexp.MustCompile(`^` + TagRegexp.String() + `$`)
+
+	// ErrTagInvalid is returned when a tag does not match TagAnchoredRegexp.
+	ErrTagInvalid = fmt.Errorf("tag name must match %q", TagRegexp.String())
+)
+
+// Tag represents an image's tag name.
+type Tag string
+
+// NewTag returns a valid Tag from an input string s.
+// If the validation fails, an error is returned.
+func NewTag(s string) (Tag, error) {
+	tag := Tag(s)
+	return tag, tag.Validate()
+}
+
+// Validate returns ErrTagInvalid if tag does not match TagAnchoredRegexp.
+//
+//	tag	:= [\w][\w.-]{0,127}
+func (tag Tag) Validate() error {
+	if !TagAnchoredRegexp.MatchString(string(tag)) {
+		return ErrTagInvalid
+	}
+	return nil
+}

registry/api/v2/descriptors.go

@@ -5,6 +5,7 @@ import (
 	"regexp"
 
 	"github.com/docker/distribution/digest"
+	"github.com/docker/distribution/reference"
 	"github.com/docker/distribution/registry/api/errcode"
 )
 
@@ -12,7 +13,7 @@ var (
 	nameParameterDescriptor = ParameterDescriptor{
 		Name:        "name",
 		Type:        "string",
-		Format:      RepositoryNameRegexp.String(),
+		Format:      reference.RepositoryNameRegexp.String(),
 		Required:    true,
 		Description: `Name of the target repository.`,
 	}
@@ -20,7 +21,7 @@ var (
 	referenceParameterDescriptor = ParameterDescriptor{
 		Name:        "reference",
 		Type:        "string",
-		Format:      TagNameRegexp.String(),
+		Format:      reference.TagRegexp.String(),
 		Required:    true,
 		Description: `Tag or digest of the target manifest.`,
 	}
@@ -389,7 +390,7 @@ var routeDescriptors = []RouteDescriptor{
 	},
 	{
 		Name:        RouteNameTags,
-		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/tags/list",
+		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/tags/list",
 		Entity:      "Tags",
 		Description: "Retrieve information about tags.",
 		Methods: []MethodDescriptor{
@@ -517,7 +518,7 @@ var routeDescriptors = []RouteDescriptor{
 	},
 	{
 		Name:        RouteNameManifest,
-		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/manifests/{reference:" + TagNameRegexp.String() + "|" + digest.DigestRegexp.String() + "}",
+		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/manifests/{reference:" + reference.TagRegexp.String() + "|" + digest.DigestRegexp.String() + "}",
 		Entity:      "Manifest",
 		Description: "Create, update, delete and retrieve manifests.",
 		Methods: []MethodDescriptor{
@@ -782,7 +783,7 @@ var routeDescriptors = []RouteDescriptor{
 
 	{
 		Name:        RouteNameBlob,
-		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/blobs/{digest:" + digest.DigestRegexp.String() + "}",
+		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/blobs/{digest:" + digest.DigestRegexp.String() + "}",
 		Entity:      "Blob",
 		Description: "Operations on blobs identified by `name` and `digest`. Used to fetch or delete layers by digest.",
 		Methods: []MethodDescriptor{
@@ -1006,7 +1007,7 @@ var routeDescriptors = []RouteDescriptor{
 
 	{
 		Name:        RouteNameBlobUpload,
-		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/blobs/uploads/",
+		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/blobs/uploads/",
 		Entity:      "Initiate Blob Upload",
 		Description: "Initiate a blob upload. This endpoint can be used to create resumable uploads or monolithic uploads.",
 		Methods: []MethodDescriptor{
@@ -1128,7 +1129,7 @@ var routeDescriptors = []RouteDescriptor{
 
 	{
 		Name:        RouteNameBlobUploadChunk,
-		Path:        "/v2/{name:" + RepositoryNameRegexp.String() + "}/blobs/uploads/{uuid:[a-zA-Z0-9-_.=]+}",
+		Path:        "/v2/{name:" + reference.RepositoryNameRegexp.String() + "}/blobs/uploads/{uuid:[a-zA-Z0-9-_.=]+}",
 		Entity:      "Blob Upload",
 		Description: "Interact with blob uploads. Clients should never assemble URLs for this endpoint and should only take it through the `Location` header on related API requests. The `Location` header and its parameters should be preserved by clients, using the latest value returned via upload related API calls.",
 		Methods: []MethodDescriptor{

registry/api/v2/names.go

@@ -1,96 +0,0 @@
-package v2
-
-import (
-	"fmt"
-	"regexp"
-	"strings"
-)
-
-// TODO(stevvooe): Move these definitions to the future "reference" package.
-// While they are used with v2 definitions, their relevance expands beyond.
-
-const (
-	// RepositoryNameTotalLengthMax is the maximum total number of characters in
-	// a repository name
-	RepositoryNameTotalLengthMax = 255
-)
-
-// domainLabelRegexp represents the following RFC-2396 BNF construct:
-//   domainlabel   = alphanum | alphanum *( alphanum | "-" ) alphanum
-var domainLabelRegexp = regexp.MustCompile(`[a-z0-9](?:-*[a-z0-9])*`)
-
-// RepositoryNameComponentRegexp restricts registry path component names to
-// the allow valid hostnames according to: https://www.ietf.org/rfc/rfc2396.txt
-// with the following differences:
-//  1) It DOES NOT allow for fully-qualified domain names, which include a
-//    trailing '.', e.g. "google.com."
-//  2) It DOES NOT restrict 'top-level' domain labels to start with just alpha
-//    characters.
-//  3) It DOES allow for underscores to appear in the same situations as dots.
-//
-// RFC-2396 uses the BNF construct:
-//   hostname      = *( domainlabel "." ) toplabel [ "." ]
-var RepositoryNameComponentRegexp = regexp.MustCompile(
-	domainLabelRegexp.String() + `(?:[._]` + domainLabelRegexp.String() + `)*`)
-
-// RepositoryNameComponentAnchoredRegexp is the version of
-// RepositoryNameComponentRegexp which must completely match the content
-var RepositoryNameComponentAnchoredRegexp = regexp.MustCompile(`^` + RepositoryNameComponentRegexp.String() + `$`)
-
-// RepositoryNameRegexp builds on RepositoryNameComponentRegexp to allow
-// multiple path components, separated by a forward slash.
-var RepositoryNameRegexp = regexp.MustCompile(`(?:` + RepositoryNameComponentRegexp.String() + `/)*` + RepositoryNameComponentRegexp.String())
-
-// TagNameRegexp matches valid tag names. From docker/docker:graph/tags.go.
-var TagNameRegexp = regexp.MustCompile(`[\w][\w.-]{0,127}`)
-
-// TagNameAnchoredRegexp matches valid tag names, anchored at the start and
-// end of the matched string.
-var TagNameAnchoredRegexp = regexp.MustCompile("^" + TagNameRegexp.String() + "$")
-
-var (
-	// ErrRepositoryNameEmpty is returned for empty, invalid repository names.
-	ErrRepositoryNameEmpty = fmt.Errorf("repository name must have at least one component")
-
-	// ErrRepositoryNameLong is returned when a repository name is longer than
-	// RepositoryNameTotalLengthMax
-	ErrRepositoryNameLong = fmt.Errorf("repository name must not be more than %v characters", RepositoryNameTotalLengthMax)
-
-	// ErrRepositoryNameComponentInvalid is returned when a repository name does
-	// not match RepositoryNameComponentRegexp
-	ErrRepositoryNameComponentInvalid = fmt.Errorf("repository name component must match %q", RepositoryNameComponentRegexp.String())
-)
-
-// ValidateRepositoryName ensures the repository name is valid for use in the
-// registry. This function accepts a superset of what might be accepted by
-// docker core or docker hub. If the name does not pass validation, an error,
-// describing the conditions, is returned.
-//
-// Effectively, the name should comply with the following grammar:
-//
-// 	alpha-numeric := /[a-z0-9]+/
-//	separator := /[._-]/
-//	component := alpha-numeric [separator alpha-numeric]*
-//	namespace := component ['/' component]*
-//
-// The result of the production, known as the "namespace", should be limited
-// to 255 characters.
-func ValidateRepositoryName(name string) error {
-	if name == "" {
-		return ErrRepositoryNameEmpty
-	}
-
-	if len(name) > RepositoryNameTotalLengthMax {
-		return ErrRepositoryNameLong
-	}
-
-	components := strings.Split(name, "/")
-
-	for _, component := range components {
-		if !RepositoryNameComponentAnchoredRegexp.MatchString(component) {
-			return ErrRepositoryNameComponentInvalid
-		}
-	}
-
-	return nil
-}

registry/client/repository.go

@@ -15,6 +15,7 @@ import (
 	"github.com/docker/distribution/context"
 	"github.com/docker/distribution/digest"
 	"github.com/docker/distribution/manifest/schema1"
+	"github.com/docker/distribution/reference"
 	"github.com/docker/distribution/registry/api/v2"
 	"github.com/docker/distribution/registry/client/transport"
 	"github.com/docker/distribution/registry/storage/cache"
@@ -96,9 +97,9 @@ func (r *registry) Repositories(ctx context.Context, entries []string, last stri
 	return numFilled, returnErr
 }
 
-// NewRepository creates a new Repository for the given repository name and base URL
+// NewRepository creates a new Repository for the given canonical repository name and base URL.
-func NewRepository(ctx context.Context, name, baseURL string, transport http.RoundTripper) (distribution.Repository, error) {
+func NewRepository(ctx context.Context, canonicalName, baseURL string, transport http.RoundTripper) (distribution.Repository, error) {
-	if err := v2.ValidateRepositoryName(name); err != nil {
+	if _, err := reference.NewRepository(canonicalName); err != nil {
 		return nil, err
 	}
 
@@ -115,7 +116,7 @@ func NewRepository(ctx context.Context, name, baseURL string, transport http.Rou
 	return &repository{
 		client:  client,
 		ub:      ub,
-		name:    name,
+		name:    canonicalName,
 		context: ctx,
 	}, nil
 }

registry/storage/cache/memory/memory.go

@@ -6,7 +6,7 @@ import (
 	"github.com/docker/distribution"
 	"github.com/docker/distribution/context"
 	"github.com/docker/distribution/digest"
-	"github.com/docker/distribution/registry/api/v2"
+	"github.com/docker/distribution/reference"
 	"github.com/docker/distribution/registry/storage/cache"
 )
 
@@ -25,8 +25,8 @@ func NewInMemoryBlobDescriptorCacheProvider() cache.BlobDescriptorCacheProvider
 	}
 }
 
-func (imbdcp *inMemoryBlobDescriptorCacheProvider) RepositoryScoped(repo string) (distribution.BlobDescriptorService, error) {
+func (imbdcp *inMemoryBlobDescriptorCacheProvider) RepositoryScoped(canonicalName string) (distribution.BlobDescriptorService, error) {
-	if err := v2.ValidateRepositoryName(repo); err != nil {
+	if _, err := reference.NewRepository(canonicalName); err != nil {
 		return nil, err
 	}
 
@@ -34,9 +34,9 @@ func (imbdcp *inMemoryBlobDescriptorCacheProvider) RepositoryScoped(repo string)
 	defer imbdcp.mu.RUnlock()
 
 	return &repositoryScopedInMemoryBlobDescriptorCache{
-		repo:       repo,
+		repo:       canonicalName,
 		parent:     imbdcp,
-		repository: imbdcp.repositories[repo],
+		repository: imbdcp.repositories[canonicalName],
 	}, nil
 }
 

registry/storage/cache/redis/redis.go

@@ -6,7 +6,7 @@ import (
 	"github.com/docker/distribution"
 	"github.com/docker/distribution/context"
 	"github.com/docker/distribution/digest"
-	"github.com/docker/distribution/registry/api/v2"
+	"github.com/docker/distribution/reference"
 	"github.com/docker/distribution/registry/storage/cache"
 	"github.com/garyburd/redigo/redis"
 )
@@ -40,13 +40,13 @@ func NewRedisBlobDescriptorCacheProvider(pool *redis.Pool) cache.BlobDescriptorC
 }
 
 // RepositoryScoped returns the scoped cache.
-func (rbds *redisBlobDescriptorService) RepositoryScoped(repo string) (distribution.BlobDescriptorService, error) {
+func (rbds *redisBlobDescriptorService) RepositoryScoped(canonicalName string) (distribution.BlobDescriptorService, error) {
-	if err := v2.ValidateRepositoryName(repo); err != nil {
+	if _, err := reference.NewRepository(canonicalName); err != nil {
 		return nil, err
 	}
 
 	return &repositoryScopedRedisBlobDescriptorService{
-		repo:     repo,
+		repo:     canonicalName,
 		upstream: rbds,
 	}, nil
 }

registry/storage/registry.go

@@ -3,7 +3,7 @@ package storage
 import (
 	"github.com/docker/distribution"
 	"github.com/docker/distribution/context"
-	"github.com/docker/distribution/registry/api/v2"
+	"github.com/docker/distribution/reference"
 	"github.com/docker/distribution/registry/storage/cache"
 	storagedriver "github.com/docker/distribution/registry/storage/driver"
 )
@@ -107,10 +107,10 @@ func (reg *registry) Scope() distribution.Scope {
 // Repository returns an instance of the repository tied to the registry.
 // Instances should not be shared between goroutines but are cheap to
 // allocate. In general, they should be request scoped.
-func (reg *registry) Repository(ctx context.Context, name string) (distribution.Repository, error) {
+func (reg *registry) Repository(ctx context.Context, canonicalName string) (distribution.Repository, error) {
-	if err := v2.ValidateRepositoryName(name); err != nil {
+	if _, err := reference.NewRepository(canonicalName); err != nil {
 		return nil, distribution.ErrRepositoryNameInvalid{
-			Name:   name,
+			Name:   canonicalName,
 			Reason: err,
 		}
 	}
@@ -118,7 +118,7 @@ func (reg *registry) Repository(ctx context.Context, name string) (distribution.
 	var descriptorCache distribution.BlobDescriptorService
 	if reg.blobDescriptorCacheProvider != nil {
 		var err error
-		descriptorCache, err = reg.blobDescriptorCacheProvider.RepositoryScoped(name)
+		descriptorCache, err = reg.blobDescriptorCacheProvider.RepositoryScoped(canonicalName)
 		if err != nil {
 			return nil, err
 		}
@@ -127,7 +127,7 @@ func (reg *registry) Repository(ctx context.Context, name string) (distribution.
 	return &repository{
 		ctx:             ctx,
 		registry:        reg,
-		name:            name,
+		name:            canonicalName,
 		descriptorCache: descriptorCache,
 	}, nil
 }