Move registry api definitions under registry package

Signed-off-by: Stephen J Day <stephen.day@docker.com>

docs/api/v2/names.go

@@ -0,0 +1,115 @@
+package v2
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+const (
+	// RepositoryNameComponentMinLength is the minimum number of characters in a
+	// single repository name slash-delimited component
+	RepositoryNameComponentMinLength = 2
+
+	// RepositoryNameComponentMaxLength is the maximum number of characters in a
+	// single repository name slash-delimited component
+	RepositoryNameComponentMaxLength = 30
+
+	// RepositoryNameMinComponents is the minimum number of slash-delimited
+	// components that a repository name must have
+	RepositoryNameMinComponents = 1
+
+	// RepositoryNameMaxComponents is the maximum number of slash-delimited
+	// components that a repository name must have
+	RepositoryNameMaxComponents = 5
+
+	// RepositoryNameTotalLengthMax is the maximum total number of characters in
+	// a repository name
+	RepositoryNameTotalLengthMax = 255
+)
+
+// RepositoryNameComponentRegexp restricts registtry path components names to
+// start with at least two letters or numbers, with following parts able to
+// separated by one period, dash or underscore.
+var RepositoryNameComponentRegexp = regexp.MustCompile(`[a-z0-9]+(?:[._-][a-z0-9]+)*`)
+
+// RepositoryNameComponentAnchoredRegexp is the version of
+// RepositoryNameComponentRegexp which must completely match the content
+var RepositoryNameComponentAnchoredRegexp = regexp.MustCompile(`^` + RepositoryNameComponentRegexp.String() + `$`)
+
+// TODO(stevvooe): RepositoryName needs to be limited to some fixed length.
+// Looking path prefixes and s3 limitation of 1024, this should likely be
+// around 512 bytes. 256 bytes might be more manageable.
+
+// RepositoryNameRegexp builds on RepositoryNameComponentRegexp to allow 1 to
+// 5 path components, separated by a forward slash.
+var RepositoryNameRegexp = regexp.MustCompile(`(?:` + RepositoryNameComponentRegexp.String() + `/){0,4}` + RepositoryNameComponentRegexp.String())
+
+// TagNameRegexp matches valid tag names. From docker/docker:graph/tags.go.
+var TagNameRegexp = regexp.MustCompile(`[\w][\w.-]{0,127}`)
+
+// TODO(stevvooe): Contribute these exports back to core, so they are shared.
+
+var (
+	// ErrRepositoryNameComponentShort is returned when a repository name
+	// contains a component which is shorter than
+	// RepositoryNameComponentMinLength
+	ErrRepositoryNameComponentShort = fmt.Errorf("respository name component must be %v or more characters", RepositoryNameComponentMinLength)
+
+	// ErrRepositoryNameComponentLong is returned when a repository name
+	// contains a component which is longer than
+	// RepositoryNameComponentMaxLength
+	ErrRepositoryNameComponentLong = fmt.Errorf("respository name component must be %v characters or less", RepositoryNameComponentMaxLength)
+
+	// ErrRepositoryNameMissingComponents is returned when a repository name
+	// contains fewer than RepositoryNameMinComponents components
+	ErrRepositoryNameMissingComponents = fmt.Errorf("repository name must have at least %v components", RepositoryNameMinComponents)
+
+	// ErrRepositoryNameTooManyComponents is returned when a repository name
+	// contains more than RepositoryNameMaxComponents components
+	ErrRepositoryNameTooManyComponents = fmt.Errorf("repository name %v or less components", RepositoryNameMaxComponents)
+
+	// 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())
+)
+
+// ValidateRespositoryName 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.
+func ValidateRespositoryName(name string) error {
+	if len(name) > RepositoryNameTotalLengthMax {
+		return ErrRepositoryNameLong
+	}
+
+	components := strings.Split(name, "/")
+
+	if len(components) < RepositoryNameMinComponents {
+		return ErrRepositoryNameMissingComponents
+	}
+
+	if len(components) > RepositoryNameMaxComponents {
+		return ErrRepositoryNameTooManyComponents
+	}
+
+	for _, component := range components {
+		if len(component) < RepositoryNameComponentMinLength {
+			return ErrRepositoryNameComponentShort
+		}
+
+		if len(component) > RepositoryNameComponentMaxLength {
+			return ErrRepositoryNameComponentLong
+		}
+
+		if !RepositoryNameComponentAnchoredRegexp.MatchString(component) {
+			return ErrRepositoryNameComponentInvalid
+		}
+	}
+
+	return nil
+}