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/bitmex/bitmex_test.go

@@ -1090,3 +1090,18 @@ func TestGetHistoricTrades(t *testing.T) {
 		t.Error(err)
 	}
 }
+
+func TestUpdateTicker(t *testing.T) {
+	cp := currency.NewPair(currency.ETH, currency.USD)
+	_, err := b.UpdateTicker(cp, asset.PerpetualContract)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestUpdateTickers(t *testing.T) {
+	err := b.UpdateTickers(asset.Spot)
+	if err != nil {
+		t.Fatal(err)
+	}
+}

exchanges/bitmex/bitmex_wrapper.go

@@ -279,21 +279,16 @@ func (b *Bitmex) UpdateTradablePairs(forceUpdate bool) error {
 	return nil
 }
 
-// UpdateTicker updates and returns the ticker for a currency pair
-func (b *Bitmex) UpdateTicker(p currency.Pair, assetType asset.Item) (*ticker.Price, error) {
-	fPair, err := b.FormatExchangeCurrency(p, assetType)
-	if err != nil {
-		return nil, err
-	}
-
+// UpdateTickers updates the ticker for all currency pairs of a given asset type
+func (b *Bitmex) UpdateTickers(a asset.Item) error {
 	tick, err := b.GetActiveAndIndexInstruments()
 	if err != nil {
-		return nil, err
+		return err
 	}
 
-	pairs, err := b.GetEnabledPairs(assetType)
+	pairs, err := b.GetEnabledPairs(a)
 	if err != nil {
-		return nil, err
+		return err
 	}
 
 	for j := range tick {
@@ -312,12 +307,27 @@ func (b *Bitmex) UpdateTicker(p currency.Pair, assetType asset.Item) (*ticker.Pr
 			Pair:         tick[j].Symbol,
 			LastUpdated:  tick[j].Timestamp,
 			ExchangeName: b.Name,
-			AssetType:    assetType})
+			AssetType:    a})
 		if err != nil {
-			return nil, err
+			return err
 		}
 	}
-	return ticker.GetTicker(b.Name, fPair, assetType)
+	return nil
+}
+
+// UpdateTicker updates and returns the ticker for a currency pair
+func (b *Bitmex) UpdateTicker(p currency.Pair, a asset.Item) (*ticker.Price, error) {
+	err := b.UpdateTickers(a)
+	if err != nil {
+		return nil, err
+	}
+
+	fPair, err := b.FormatExchangeCurrency(p, a)
+	if err != nil {
+		return nil, err
+	}
+
+	return ticker.GetTicker(b.Name, fPair, a)
 }
 
 // FetchTicker returns the ticker for a currency pair