exchanges: Add UpdateTickers method and reserve UpdateTicker for single ticker symbol update requests (if supported) (#764)

* exchanges: add an UpdateTickers method to the main exchange interface

This method will fetch all currency pair tickers of a given asset type
and update them internally, does nothing for now.

* exchanges: refactor UpdateTicker on all exchanges

Keep the exact previous behaviour but implement the UpdateTickers
method and refactor UpdateTicker by using it where applicable.

* sync_manager: update all tickers when batching is enabled

* binance: UpdateTicker to fetch single ticker symbol

* ftx: UpdateTicker to fetch single ticker symbol

exchanges/exmo/exmo_test.go

@@ -457,3 +457,22 @@ func TestGetHistoricTrades(t *testing.T) {
 		t.Error(err)
 	}
 }
+
+func TestUpdateTicker(t *testing.T) {
+	t.Parallel()
+	cp, err := currency.NewPairFromString("BTC_USD")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = e.UpdateTicker(cp, asset.Spot)
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestUpdateTickers(t *testing.T) {
+	err := e.UpdateTickers(asset.Spot)
+	if err != nil {
+		t.Error(err)
+	}
+}

exchanges/exmo/exmo_wrapper.go

@@ -182,18 +182,15 @@ func (e *EXMO) UpdateTradablePairs(forceUpdate bool) error {
 	return e.UpdatePairs(p, asset.Spot, false, forceUpdate)
 }
 
-// UpdateTicker updates and returns the ticker for a currency pair
-func (e *EXMO) UpdateTicker(p currency.Pair, assetType asset.Item) (*ticker.Price, error) {
+// UpdateTickers updates the ticker for all currency pairs of a given asset type
+func (e *EXMO) UpdateTickers(a asset.Item) error {
 	result, err := e.GetTicker()
 	if err != nil {
-		return nil, err
+		return err
 	}
-	if _, ok := result[p.String()]; !ok {
-		return nil, err
-	}
-	pairs, err := e.GetEnabledPairs(assetType)
+	pairs, err := e.GetEnabledPairs(a)
 	if err != nil {
-		return nil, err
+		return err
 	}
 	for i := range pairs {
 		for j := range result {
@@ -210,13 +207,22 @@ func (e *EXMO) UpdateTicker(p currency.Pair, assetType asset.Item) (*ticker.Pric
 				Low:          result[j].Low,
 				Volume:       result[j].Volume,
 				ExchangeName: e.Name,
-				AssetType:    assetType})
+				AssetType:    a})
 			if err != nil {
-				return nil, err
+				return err
 			}
 		}
 	}
-	return ticker.GetTicker(e.Name, p, assetType)
+	return nil
+}
+
+// UpdateTicker updates and returns the ticker for a currency pair
+func (e *EXMO) UpdateTicker(p currency.Pair, a asset.Item) (*ticker.Price, error) {
+	err := e.UpdateTickers(a)
+	if err != nil {
+		return nil, err
+	}
+	return ticker.GetTicker(e.Name, p, a)
 }
 
 // FetchTicker returns the ticker for a currency pair