Rename top level registry interface to namespace

Registry is intended to be used as a repository service than an abstract collection of repositories. Namespace better describes a collection of repositories retrievable by name.
The registry service serves any repository in the global scope.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

docs/configuration.md

@@ -283,7 +283,7 @@ For more information about Token based authentication configuration, see the [sp
 
 ## middleware
 
-The middleware option is **optional** and allows middlewares to be injected at named hook points. A requirement of all middlewares is that they implement the same interface as the object they're wrapping. This means a registry middleware must implement the `distribution.Registry` interface, repository middleware must implement `distribution.Respository`, and storage middleware must implement `driver.StorageDriver`.
+The middleware option is **optional** and allows middlewares to be injected at named hook points. A requirement of all middlewares is that they implement the same interface as the object they're wrapping. This means a registry middleware must implement the `distribution.Namespace` interface, repository middleware must implement `distribution.Respository`, and storage middleware must implement `driver.StorageDriver`.
 
 Currently only one middleware, cloudfront, a storage middleware, is included in the registry. 
 

docs/glossary.md

@@ -23,7 +23,7 @@ see the [glossary in the full documentation set](http://docs.docker.com/referenc
 	<dd>Describes a collection layers that make up an image.</dd>
 
 	<dt>Registry</dt>
-	<dd>A registry is a collection of repositories.</dd>
+	<dd>A registry is a service which serves repositories.</dd>
 
 	<dt>Repository</dt>
 	<dd>
@@ -33,4 +33,11 @@ see the [glossary in the full documentation set](http://docs.docker.com/referenc
 
 	<dt>Tag</dt>
 	<dd>Tag provides a common name to an image.</dd>
-</dl>
+
+	<dt>Namespace</dt>
+	<dd>A namespace is a collection of repositories with a common name prefix. The
+	namespace with an empty common prefix is considered the Global Namespace.</dd>
+
+	<dt>Scope</dt>
+	<dd>A common repository name prefix.</dd>
+</dl>

registry.go

@@ -10,8 +10,31 @@ import (
 	"golang.org/x/net/context"
 )
 
-// Registry represents a collection of repositories, addressable by name.
-type Registry interface {
+// Scope defines the set of items that match a namespace.
+type Scope interface {
+	// Contains returns true if the name belongs to the namespace.
+	Contains(name string) bool
+}
+
+type fullScope struct{}
+
+func (f fullScope) Contains(string) bool {
+	return true
+}
+
+// GlobalScope represents the full namespace scope which contains
+// all other scopes.
+var GlobalScope = Scope(fullScope{})
+
+// Namespace represents a collection of repositories, addressable by name.
+// Generally, a namespace is backed by a set of one or more services,
+// providing facilities such as registry access, trust, and indexing.
+type Namespace interface {
+	// Scope describes the names that can be used with this Namespace. The
+	// global namespace will have a scope that matches all names. The scope
+	// effectively provides an identity for the namespace.
+	Scope() Scope
+
 	// Repository should return a reference to the named repository. The
 	// registry may or may not have the repository but should always return a
 	// reference.

registry/handlers/app.go

@@ -40,7 +40,7 @@ type App struct {
 
 	router           *mux.Router                 // main application router, configured with dispatchers
 	driver           storagedriver.StorageDriver // driver maintains the app global storage driver instance.
-	registry         distribution.Registry       // registry is the primary registry backend for the app instance.
+	registry         distribution.Namespace      // registry is the primary registry backend for the app instance.
 	accessController auth.AccessController       // main access controller for application
 
 	// events contains notification related configuration.
@@ -541,7 +541,7 @@ func appendAccessRecords(records []auth.Access, method string, repo string) []au
 }
 
 // applyRegistryMiddleware wraps a registry instance with the configured middlewares
-func applyRegistryMiddleware(registry distribution.Registry, middlewares []configuration.Middleware) (distribution.Registry, error) {
+func applyRegistryMiddleware(registry distribution.Namespace, middlewares []configuration.Middleware) (distribution.Namespace, error) {
 	for _, mw := range middlewares {
 		rmw, err := registrymiddleware.Get(mw.Name, mw.Options, registry)
 		if err != nil {

registry/middleware/registry/middleware.go

@@ -8,7 +8,7 @@ import (
 
 // InitFunc is the type of a RegistryMiddleware factory function and is
 // used to register the constructor for different RegistryMiddleware backends.
-type InitFunc func(registry distribution.Registry, options map[string]interface{}) (distribution.Registry, error)
+type InitFunc func(registry distribution.Namespace, options map[string]interface{}) (distribution.Namespace, error)
 
 var middlewares map[string]InitFunc
 
@@ -28,7 +28,7 @@ func Register(name string, initFunc InitFunc) error {
 }
 
 // Get constructs a RegistryMiddleware with the given options using the named backend.
-func Get(name string, options map[string]interface{}, registry distribution.Registry) (distribution.Registry, error) {
+func Get(name string, options map[string]interface{}, registry distribution.Namespace) (distribution.Namespace, error) {
 	if middlewares != nil {
 		if initFunc, exists := middlewares[name]; exists {
 			return initFunc(registry, options)

registry/storage/manifeststore_test.go

@@ -21,7 +21,7 @@ import (
 type manifestStoreTestEnv struct {
 	ctx        context.Context
 	driver     driver.StorageDriver
-	registry   distribution.Registry
+	registry   distribution.Namespace
 	repository distribution.Repository
 	name       string
 	tag        string

registry/storage/registry.go

@@ -20,7 +20,7 @@ type registry struct {
 // NewRegistryWithDriver creates a new registry instance from the provided
 // driver. The resulting registry may be shared by multiple goroutines but is
 // cheap to allocate.
-func NewRegistryWithDriver(driver storagedriver.StorageDriver, layerInfoCache cache.LayerInfoCache) distribution.Registry {
+func NewRegistryWithDriver(driver storagedriver.StorageDriver, layerInfoCache cache.LayerInfoCache) distribution.Namespace {
 	bs := &blobStore{
 		driver: driver,
 		pm:     defaultPathMapper,
@@ -36,6 +36,12 @@ func NewRegistryWithDriver(driver storagedriver.StorageDriver, layerInfoCache ca
 	}
 }
 
+// Scope returns the namespace scope for a registry. The registry
+// will only serve repositories contained within this scope.
+func (reg *registry) Scope() distribution.Scope {
+	return distribution.GlobalScope
+}
+
 // 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.