add unknown service handler

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

grpc.go

@@ -145,7 +145,7 @@ func (g *grpcServer) configure(opts ...server.Option) error {
 	}
 
 	if opts := g.getGrpcOptions(); opts != nil {
-		gopts = append(gopts, opts...)
+		gopts = append(opts, gopts...)
 	}
 
 	g.rsvc = nil
@@ -329,12 +329,22 @@ func (g *grpcServer) handler(srv interface{}, stream grpc.ServerStream) (err err
 	*/
 
 	if svc == nil {
+		if g.opts.Context != nil {
+			if h, ok := g.opts.Context.Value(unknownServiceHandlerKey{}).(grpc.StreamHandler); ok {
+				return h(srv, stream)
+			}
+		}
 		return status.New(codes.Unimplemented, fmt.Sprintf("unknown service %s", serviceName)).Err()
 	}
 
 	mtype := svc.method[methodName]
 	if mtype == nil {
-		return status.New(codes.Unimplemented, fmt.Sprintf("unknown service %s.%s", serviceName, methodName)).Err()
+		if g.opts.Context != nil {
+			if h, ok := g.opts.Context.Value(unknownServiceHandlerKey{}).(grpc.StreamHandler); ok {
+				return h(srv, stream)
+			}
+		}
+		return status.New(codes.Unimplemented, fmt.Sprintf("unknown service method %s.%s", serviceName, methodName)).Err()
 	}
 
 	// process unary

options.go

@@ -9,10 +9,11 @@ import (
 )
 
 type (
-	codecsKey     struct{}
-	grpcOptions   struct{}
-	maxMsgSizeKey struct{}
-	reflectionKey struct{}
+	codecsKey                struct{}
+	grpcOptions              struct{}
+	maxMsgSizeKey            struct{}
+	reflectionKey            struct{}
+	unknownServiceHandlerKey struct{}
 )
 
 // gRPC Codec to be used to encode/decode requests for a given content type
@@ -37,8 +38,7 @@ func Options(opts ...grpc.ServerOption) server.Option {
 
 //
 // MaxMsgSize set the maximum message in bytes the server can receive and
-// send.  Default maximum message size is 4 MB.
-//
+// send. Default maximum message size is 4 MB.
 func MaxMsgSize(s int) server.Option {
 	return server.SetOption(maxMsgSizeKey{}, s)
 }
@@ -47,3 +47,8 @@ func MaxMsgSize(s int) server.Option {
 func Reflection(b bool) server.Option {
 	return server.SetOption(reflectionKey{}, b)
 }
+
+// UnknownServiceHandler enables support for all services
+func UnknownServiceHandler(h grpc.StreamHandler) server.Option {
+	return server.SetOption(unknownServiceHandlerKey{}, h)
+}