add needed files

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

error.go

@@ -0,0 +1,44 @@
+package drpc
+
+import (
+	"github.com/unistack-org/micro/v3/errors"
+	"google.golang.org/grpc/status"
+)
+
+func microError(err error) error {
+	// no error
+
+	if err == nil {
+		return nil
+	}
+
+	if verr, ok := err.(*errors.Error); ok {
+		return verr
+	}
+
+	// grpc error
+	s, ok := status.FromError(err)
+	if !ok {
+		return err
+	}
+
+	// return first error from details
+	if details := s.Details(); len(details) > 0 {
+		if verr, ok := details[0].(error); ok {
+			return microError(verr)
+		}
+	}
+
+	// try to decode micro *errors.Error
+	if e := errors.Parse(s.Message()); e.Code > 0 {
+		return e // actually a micro error
+	}
+
+	// fallback
+	return &errors.Error{
+		Id:     "go.micro.client",
+		Code:   int32(s.Code()),
+		Detail: s.Message(),
+		Status: s.Code().String(),
+	}
+}