fix bot panicing when it cannot cast data from ccxtExchange, fixes #31

plugins/ccxtExchange.go

@@ -49,9 +49,18 @@ func (c ccxtExchange) GetTickerPrice(pairs []model.TradingPair) (map[model.Tradi
 			return nil, fmt.Errorf("error while fetching ticker price for trading pair %s: %s", pairsMap[p], e)
 		}
 
+		askPrice, e := utils.CheckFetchFloat(tickerMap, "ask")
+		if e != nil {
+			return nil, fmt.Errorf("unable to correctly fetch value from tickerMap: %s", e)
+		}
+		bidPrice, e := utils.CheckFetchFloat(tickerMap, "bid")
+		if e != nil {
+			return nil, fmt.Errorf("unable to correctly fetch value from tickerMap: %s", e)
+		}
+
 		priceResult[p] = api.Ticker{
-			AskPrice: model.NumberFromFloat(tickerMap["ask"].(float64), c.precision),
-			BidPrice: model.NumberFromFloat(tickerMap["bid"].(float64), c.precision),
+			AskPrice: model.NumberFromFloat(askPrice, c.precision),
+			BidPrice: model.NumberFromFloat(bidPrice, c.precision),
 		}
 	}
 

support/utils/functions.go

@@ -210,3 +210,18 @@ func AssetsEqual(baseAsset base.Asset, horizonAsset horizon.Asset) bool {
 		horizonAsset.Code == baseAsset.Code &&
 		horizonAsset.Issuer == baseAsset.Issuer
 }
+
+// CheckFetchFloat tries to fetch and then cast the value for the provided key
+func CheckFetchFloat(m map[string]interface{}, key string) (float64, error) {
+	v, ok := m[key]
+	if !ok {
+		return 0.0, fmt.Errorf("'%s' field not in map", key)
+	}
+
+	f, ok := v.(float64)
+	if !ok {
+		return 0.0, fmt.Errorf("unable to cast '%s' field to float64, value: %v", key, v)
+	}
+
+	return f, nil
+}