private object AppPreMonthChartData(string appId, List <string> levels) { var app = _memoryCache.Get <App>($"app_{appId}"); if (app == null) { app = _appRepository.Get(appId); } var startDate = DateTime.Now.AddDays(-30); var appName = string.IsNullOrEmpty(appId) ? "" : app.Name; var result = _traceRepository.GroupLevel(levels, appId, startDate, DateTime.Now); return(new { appName, data = result }); }