Add const for option name

Signed-off-by: Oleg Bulatov <[email protected]>

pkg/dockerregistry/server/auth.go

@@ -45,6 +45,8 @@ const (
 
 	RealmKey      = "realm"
 	TokenRealmKey = "tokenrealm"
+
+	accessControllerOptionContext = "_context"
 )
 
 // RegistryClient encapsulates getting access to the OpenShift API.
@@ -164,7 +166,7 @@ func TokenRealm(options map[string]interface{}) (*url.URL, error) {
 func newAccessController(options map[string]interface{}) (registryauth.AccessController, error) {
 	log.Info("Using Origin Auth handler")
 
-	ctx, ok := options["_context"].(context.Context)
+	ctx, ok := options[accessControllerOptionContext].(context.Context)
 	if !ok {
 		return nil, fmt.Errorf("no context provided to Origin Auth handler")
 	}

pkg/dockerregistry/server/auth_test.go

@@ -393,13 +393,16 @@ func TestAccessController(t *testing.T) {
 		}
 
 		server, actions := simulateOpenShiftMaster(test.openshiftResponses)
-		options["_context"] = WithRegistryClient(context.Background(), NewRegistryClient(&clientcmd.Config{
-			CommonConfig: restclient.Config{
-				Host:     server.URL,
-				Insecure: true,
-			},
-			SkipEnv: true,
-		}))
+		options[accessControllerOptionContext] = WithRegistryClient(
+			context.Background(),
+			NewRegistryClient(&clientcmd.Config{
+				CommonConfig: restclient.Config{
+					Host:     server.URL,
+					Insecure: true,
+				},
+				SkipEnv: true,
+			}),
+		)
 		accessController, err := newAccessController(options)
 		if err != nil {
 			t.Fatal(err)