better message formatting

api/notification/internal/server/notificationimp/mail/internal/builder/builder.go

@@ -42,7 +42,7 @@ func (mb *MessageBuilderImp) AddData(key, value string) mmail.MailBuilder {
 
 func (mb *MessageBuilderImp) Build() (mmail.Message, error) {
 	if len(mb.message.recipients) == 0 {
-		return nil, merrors.InvalidArgument("Recipient not set")
+		return nil, merrors.InvalidArgument("Recipient not set", "recipients")
 	}
 	return mb.message, nil
 }

api/notification/internal/server/notificationimp/mail/internal/mailimp.go

@@ -69,7 +69,7 @@ func (c *Client) Send(r mmail.MailBuilder) error {
 		c.logger.Warn("Malformed messge", zap.String("template_id", m.TemplateID()),
 			zap.String("locale", m.Locale()), zap.Strings("recipients", m.Recipients()),
 			zap.Int("body_size", len(body)))
-		return merrors.InvalidArgument("malformed message")
+		return merrors.InvalidArgument("malformed message", "message.body", "message.recipients")
 	}
 	subj, err := mailkey.Subject(c.l, m.Parameters(), m.TemplateID(), m.Locale())
 	if err != nil {