Add support for REST server extensions

Signed-off-by: Grant Griffiths <[email protected]>

api/server/sdk/rest_gateway.go

@@ -89,6 +89,19 @@ func (s *sdkRestGateway) Stop() {
 	}
 }
 
+// registerServerExtensions registers any extra server extensions
+// on the SDK REST Gateway server.
+func (s *sdkRestGateway) registerServerExtensions(
+	mux *runtime.ServeMux, conn *grpc.ClientConn) error {
+	for _, ext := range s.config.RestServerExtensions {
+		if err := ext(mux, conn); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // restServerSetupHandlers sets up the handlers to the swagger ui and
 // to the gRPC REST Gateway.
 func (s *sdkRestGateway) restServerSetupHandlers() (http.Handler, error) {
@@ -155,6 +168,11 @@ func (s *sdkRestGateway) restServerSetupHandlers() (http.Handler, error) {
 		}
 	}
 
+	// Register extra services provided
+	if err := s.registerServerExtensions(gmux, conn); err != nil {
+		return nil, err
+	}
+
 	// Pass all other unhandled paths to the gRPC gateway
 	mux.Handle("/", gmux)
 

api/server/sdk/server.go

@@ -25,6 +25,7 @@ import (
 
 	grpc_middleware "github.com/grpc-ecosystem/go-grpc-middleware"
 	grpc_auth "github.com/grpc-ecosystem/go-grpc-middleware/auth"
+	"github.com/grpc-ecosystem/grpc-gateway/runtime"
 	"github.com/libopenstorage/openstorage/alerts"
 	"github.com/libopenstorage/openstorage/api"
 	"github.com/libopenstorage/openstorage/api/spec"
@@ -118,7 +119,15 @@ type ServerConfig struct {
 	// 		func(gs *grpc.Server) {
 	//			api.RegisterCustomService(gs, customHandler)
 	//		})
-	ServerExtensions []func(s *grpc.Server)
+	GrpcServerExtensions []func(grpcServer *grpc.Server)
+
+	// RestServerExtensions allows for extensions to be added
+	// to the SDK Rest Gateway server.
+	//
+	// To add your own service to the SDK REST Server, simply register it
+	// on the http.ServeMux. You may also provide a grpc.ClientConn for
+	// REST Gateway services that are linked to the gRPC server.
+	RestServerExtensions []func(mux *runtime.ServeMux, conn *grpc.ClientConn) error
 }
 
 // Server is an implementation of the gRPC SDK interface
@@ -464,7 +473,7 @@ func (s *sdkGrpcServer) Start() error {
 			api.RegisterOpenStorageRoleServer(grpcServer, s.roleServer)
 		}
 
-		s.RegisterServerExtensions(grpcServer)
+		s.registerServerExtensions(grpcServer)
 
 		return grpcServer
 	})
@@ -475,8 +484,8 @@ func (s *sdkGrpcServer) Start() error {
 	return nil
 }
 
-func (s *sdkGrpcServer) RegisterServerExtensions(grpcServer *grpc.Server) {
-	for _, ext := range s.config.ServerExtensions {
+func (s *sdkGrpcServer) registerServerExtensions(grpcServer *grpc.Server) {
+	for _, ext := range s.config.GrpcServerExtensions {
 		ext(grpcServer)
 	}
 }