fix: pull out time.now variable

pkg/cmd/backtest.go

@@ -662,6 +662,7 @@ func sync(ctx context.Context, userConfig *bbgo.Config, backtestService *service
 				supportIntervals = types.SupportedIntervals
 			}
 
+			now := time.Now()
 			for interval := range supportIntervals {
 				// if err := s.SyncKLineByInterval(ctx, exchange, symbol, interval, startTime, endTime); err != nil {
 				//	return err
@@ -674,11 +675,13 @@ func sync(ctx context.Context, userConfig *bbgo.Config, backtestService *service
 				// if we don't have klines before the start time endpoint, the back-test will fail.
 				// because the last price will be missing.
 				if firstKLine != nil {
-					if err := backtestService.SyncExist(ctx, sourceExchange, symbol, syncFromTime, time.Now(), interval); err != nil {
+					log.Debugf("found existing kline data using partial sync...")
+					if err := backtestService.SyncExist(ctx, sourceExchange, symbol, syncFromTime, now, interval); err != nil {
 						return err
 					}
 				} else {
-					if err := backtestService.Sync(ctx, sourceExchange, symbol, syncFromTime, time.Now(), interval); err != nil {
+					log.Debugf("starting a fresh kline data sync...")
+					if err := backtestService.Sync(ctx, sourceExchange, symbol, syncFromTime, now, interval); err != nil {
 						return err
 					}
 				}

pkg/service/backtest.go

@@ -289,25 +289,14 @@ func (s *BacktestService) scanRows(rows *sqlx.Rows) (klines []types.KLine, err e
 }
 
 func (s *BacktestService) _targetKlineTable(exchangeName types.ExchangeName) string {
-	switch exchangeName {
+	return strings.ToLower(exchangeName.String()) + "_klines"
-	case types.ExchangeBinance:
-		return "binance_klines"
-	case types.ExchangeFTX:
-		return "ftx_klines"
-	case types.ExchangeMax:
-		return "max_klines"
-	case types.ExchangeOKEx:
-		return "okex_klines"
-	case types.ExchangeKucoin:
-		return "kucoin_klines"
-	default:
-		return "klines"
-	}
 }
 
+var errExchangeFieldIsUnset = errors.New("kline.Exchange field should not be empty")
+
 func (s *BacktestService) Insert(kline types.KLine) error {
 	if len(kline.Exchange) == 0 {
-		return errors.New("kline.Exchange field should not be empty")
+		return errExchangeFieldIsUnset
 	}
 
 	tableName := s._targetKlineTable(kline.Exchange)

pkg/service/sync_task.go

@@ -19,12 +19,16 @@ type SyncTask struct {
 	Type interface{}
 
 	// ID is a function that returns the unique identity of the object
+	// This function will be used for detecting duplicated objects.
 	ID func(obj interface{}) string
 
 	// Time is a function that returns the time of the object
+	// This function will be used for sorting records
 	Time func(obj interface{}) time.Time
 
-	// Select is the select query builder for querying db records
+	// Select is the select query builder for querying existing db records
+	// The built SQL will be used for querying existing db records.
+	// And then the ID function will be used for filtering duplicated object.
 	Select squirrel.SelectBuilder
 
 	// OnLoad is an optional field, which is called when the records are loaded from the database
@@ -79,7 +83,8 @@ func (sel SyncTask) execute(ctx context.Context, db *sqlx.DB, startTime time.Tim
 	for {
 		select {
 		case <-ctx.Done():
-			return nil
+			logrus.Warnf("context is cancelled, stop syncing")
+			return ctx.Err()
 
 		case err := <-errC:
 			return err