[#83] services: Implement response sub-service for each service

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/services/accounting/response.go

@@ -0,0 +1,37 @@
+package accounting
+
+import (
+	"context"
+
+	"github.com/nspcc-dev/neofs-api-go/v2/accounting"
+	"github.com/nspcc-dev/neofs-node/pkg/services/util"
+	"github.com/nspcc-dev/neofs-node/pkg/services/util/response"
+)
+
+type responseService struct {
+	respSvc *response.Service
+
+	svc accounting.Service
+}
+
+// NewResponseService returns accounting service instance that passes internal service
+// call to response service.
+func NewResponseService(accSvc accounting.Service, respSvc *response.Service) accounting.Service {
+	return &responseService{
+		respSvc: respSvc,
+		svc:     accSvc,
+	}
+}
+
+func (s *responseService) Balance(ctx context.Context, req *accounting.BalanceRequest) (*accounting.BalanceResponse, error) {
+	resp, err := s.respSvc.HandleUnaryRequest(ctx, req,
+		func(ctx context.Context, req interface{}) (util.ResponseMessage, error) {
+			return s.svc.Balance(ctx, req.(*accounting.BalanceRequest))
+		},
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	return resp.(*accounting.BalanceResponse), nil
+}