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/zb/zb_test.go

@@ -1000,3 +1000,23 @@ func TestGetHistoricTrades(t *testing.T) {
 		t.Error(err)
 	}
 }
+
+func TestUpdateTicker(t *testing.T) {
+	t.Parallel()
+	cp, err := currency.NewPairFromString("ETH_USDT")
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = z.UpdateTicker(cp, asset.Spot)
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestUpdateTickers(t *testing.T) {
+	t.Parallel()
+	err := z.UpdateTickers(asset.Spot)
+	if err != nil {
+		t.Error(err)
+	}
+}

exchanges/zb/zb_wrapper.go

@@ -243,16 +243,16 @@ func (z *ZB) UpdateTradablePairs(forceUpdate bool) error {
 	return z.UpdatePairs(p, asset.Spot, false, forceUpdate)
 }
 
-// UpdateTicker updates and returns the ticker for a currency pair
-func (z *ZB) UpdateTicker(p currency.Pair, assetType asset.Item) (*ticker.Price, error) {
+// UpdateTickers updates the ticker for all currency pairs of a given asset type
+func (z *ZB) UpdateTickers(a asset.Item) error {
 	result, err := z.GetTickers()
 	if err != nil {
-		return nil, err
+		return err
 	}
 
-	enabledPairs, err := z.GetEnabledPairs(assetType)
+	enabledPairs, err := z.GetEnabledPairs(a)
 	if err != nil {
-		return nil, err
+		return err
 	}
 	for x := range enabledPairs {
 		// We can't use either pair format here, so format it to lower-
@@ -271,13 +271,22 @@ func (z *ZB) UpdateTicker(p currency.Pair, assetType asset.Item) (*ticker.Price,
 			Low:          result[curr].Low,
 			Volume:       result[curr].Volume,
 			ExchangeName: z.Name,
-			AssetType:    assetType})
+			AssetType:    a})
 		if err != nil {
-			return nil, err
+			return err
 		}
 	}
 
-	return ticker.GetTicker(z.Name, p, assetType)
+	return nil
+}
+
+// UpdateTicker updates and returns the ticker for a currency pair
+func (z *ZB) UpdateTicker(p currency.Pair, a asset.Item) (*ticker.Price, error) {
+	err := z.UpdateTickers(a)
+	if err != nil {
+		return nil, err
+	}
+	return ticker.GetTicker(z.Name, p, a)
 }
 
 // FetchTicker returns the ticker for a currency pair