feat(gas-oracle): support gas token volatile exchange rate (#1526)

Co-authored-by: yiweichi <yiweichi@users.noreply.github.com>
Co-authored-by: colin <102356659+colinlyguo@users.noreply.github.com>

common/version/version.go

@@ -5,7 +5,7 @@ import (
 	"runtime/debug"
 )
 
-var tag = "v4.4.65"
+var tag = "v4.4.66"
 
 var commit = func() string {
 	if info, ok := debug.ReadBuildInfo(); ok {

rollup/internal/config/relayer.go

@@ -68,12 +68,22 @@ type RelayerConfig struct {
 	FinalizeBundleWithoutProofTimeoutSec uint64 `json:"finalize_bundle_without_proof_timeout_sec"`
 }
 
+// AlternativeGasTokenConfig The configuration for handling token exchange rates when updating the gas price oracle.
+type AlternativeGasTokenConfig struct {
+	Enabled           bool    `json:"enabled"`
+	Mode              string  `json:"mode"`
+	FixedExchangeRate float64 `json:"fixed_exchange_rate"` // fixed exchange rate of L2 gas token / L1 gas token
+	TokenSymbolPair   string  `json:"token_symbol_pair"`   // The pair should be L2 gas token symbol + L1 gas token symbol
+}
+
 // GasOracleConfig The config for updating gas price oracle.
 type GasOracleConfig struct {
 	// MinGasPrice store the minimum gas price to set.
 	MinGasPrice uint64 `json:"min_gas_price"`
 	// GasPriceDiff is the minimum percentage of gas price difference to update gas oracle.
 	GasPriceDiff uint64 `json:"gas_price_diff"`
+	// AlternativeGasTokenConfig The configuration for handling token exchange rates when updating the gas price oracle.
+	AlternativeGasTokenConfig *AlternativeGasTokenConfig `json:"alternative_gas_token_config"`
 
 	// The following configs are only for updating L1 gas price, used for sender in L2.
 	// The weight for L1 base fee.

rollup/internal/controller/relayer/l1_relayer.go

@@ -21,6 +21,7 @@ import (
 	"scroll-tech/rollup/internal/config"
 	"scroll-tech/rollup/internal/controller/sender"
 	"scroll-tech/rollup/internal/orm"
+	rutils "scroll-tech/rollup/internal/utils"
 )
 
 // Layer1Relayer is responsible for updating L1 gas price oracle contract on L2.
@@ -151,6 +152,31 @@ func (r *Layer1Relayer) ProcessGasPriceOracle() {
 			baseFee = block.BaseFee
 		}
 
+		// include the token exchange rate in the fee data if alternative gas token enabled
+		if r.cfg.GasOracleConfig.AlternativeGasTokenConfig != nil && r.cfg.GasOracleConfig.AlternativeGasTokenConfig.Enabled {
+			// The exchange rate represent the number of native token on L1 required to exchange for 1 native token on L2.
+			var exchangeRate float64
+			switch r.cfg.GasOracleConfig.AlternativeGasTokenConfig.Mode {
+			case "Fixed":
+				exchangeRate = r.cfg.GasOracleConfig.AlternativeGasTokenConfig.FixedExchangeRate
+			case "BinanceApi":
+				exchangeRate, err = rutils.GetExchangeRateFromBinanceApi(r.cfg.GasOracleConfig.AlternativeGasTokenConfig.TokenSymbolPair, 5)
+				if err != nil {
+					log.Error("Failed to get gas token exchange rate from Binance api", "tokenSymbolPair", r.cfg.GasOracleConfig.AlternativeGasTokenConfig.TokenSymbolPair, "err", err)
+					return
+				}
+			default:
+				log.Error("Invalid alternative gas token mode", "mode", r.cfg.GasOracleConfig.AlternativeGasTokenConfig.Mode)
+				return
+			}
+			if exchangeRate == 0 {
+				log.Error("Invalid exchange rate", "exchangeRate", exchangeRate)
+				return
+			}
+			baseFee = uint64(math.Ceil(float64(baseFee) / exchangeRate))
+			blobBaseFee = uint64(math.Ceil(float64(blobBaseFee) / exchangeRate))
+		}
+
 		if r.shouldUpdateGasOracle(baseFee, blobBaseFee, isCurie) {
 			// It indicates the committing batch has been stuck for a long time, it's likely that the L1 gas fee spiked.
 			// If we are not committing batches due to high fees then we shouldn't update fees to prevent users from paying high l1_data_fee

rollup/internal/controller/relayer/l2_relayer.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"math"
 	"math/big"
 	"sort"
 	"strings"
@@ -324,6 +325,32 @@ func (r *Layer2Relayer) ProcessGasPriceOracle() {
 			return
 		}
 		suggestGasPriceUint64 := uint64(suggestGasPrice.Int64())
+
+		// include the token exchange rate in the fee data if alternative gas token enabled
+		if r.cfg.GasOracleConfig.AlternativeGasTokenConfig != nil && r.cfg.GasOracleConfig.AlternativeGasTokenConfig.Enabled {
+			// The exchange rate represent the number of native token on L1 required to exchange for 1 native token on L2.
+			var exchangeRate float64
+			switch r.cfg.GasOracleConfig.AlternativeGasTokenConfig.Mode {
+			case "Fixed":
+				exchangeRate = r.cfg.GasOracleConfig.AlternativeGasTokenConfig.FixedExchangeRate
+			case "BinanceApi":
+				exchangeRate, err = rutils.GetExchangeRateFromBinanceApi(r.cfg.GasOracleConfig.AlternativeGasTokenConfig.TokenSymbolPair, 5)
+				if err != nil {
+					log.Error("Failed to get gas token exchange rate from Binance api", "tokenSymbolPair", r.cfg.GasOracleConfig.AlternativeGasTokenConfig.TokenSymbolPair, "err", err)
+					return
+				}
+			default:
+				log.Error("Invalid alternative gas token mode", "mode", r.cfg.GasOracleConfig.AlternativeGasTokenConfig.Mode)
+				return
+			}
+			if exchangeRate == 0 {
+				log.Error("Invalid exchange rate", "exchangeRate", exchangeRate)
+				return
+			}
+			suggestGasPriceUint64 = uint64(math.Ceil(float64(suggestGasPriceUint64) * exchangeRate))
+			suggestGasPrice = new(big.Int).SetUint64(suggestGasPriceUint64)
+		}
+
 		expectedDelta := r.lastGasPrice * r.gasPriceDiff / gasPriceDiffPrecision
 		if r.lastGasPrice > 0 && expectedDelta == 0 {
 			expectedDelta = 1

rollup/internal/utils/exchange_rate.go

@@ -0,0 +1,73 @@
+package utils
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/scroll-tech/go-ethereum/log"
+)
+
+var BinanceApiEndpoint string = "https://api.binance.com/api/v3/ticker/price?symbol=%s"
+
+type BinanceResponse struct {
+	Price string `json:"price"`
+}
+
+func GetExchangeRateFromBinanceApi(tokenSymbolPair string, maxRetries int) (float64, error) {
+	for i := 0; i < maxRetries; i++ {
+		if i > 0 {
+			time.Sleep(5 * time.Second)
+		}
+
+		// make HTTP GET request
+		resp, err := http.Get(fmt.Sprintf(BinanceApiEndpoint, tokenSymbolPair))
+		if err != nil {
+			log.Error("error making HTTP request", "err", err)
+			continue
+		}
+		defer func() {
+			err = resp.Body.Close()
+			if err != nil {
+				log.Error("error closing response body", "err", err)
+			}
+		}()
+
+		// check for successful response
+		if resp.StatusCode != http.StatusOK {
+			log.Error("unexpected status code", "code", resp.StatusCode)
+			continue
+		}
+
+		// read response body
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			log.Error("error reading response body", "err", err)
+			continue
+		}
+
+		// unmarshal JSON response
+		var data BinanceResponse
+		err = json.Unmarshal(body, &data)
+		if err != nil {
+			log.Error("error unmarshaling JSON", "err", err)
+			continue
+		}
+
+		// convert price string to float64
+		price, err := strconv.ParseFloat(data.Price, 64)
+		if err != nil {
+			log.Error("error parsing price string", "err", err)
+			continue
+		}
+
+		// successful response, return price
+		return price, nil
+	}
+
+	// all retries failed, return error
+	return 0, fmt.Errorf("failed to get exchange rate after %d retries", maxRetries)
+}