feat: introduce gas multiplier on jsonrpc endpoint (#128)

* introduce gas multiplier

* fix to use cfg vaule

jsonrpc/backend/backend.go

@@ -12,6 +12,7 @@ import (
 	lrucache "github.com/hashicorp/golang-lru/v2"
 
 	"cosmossdk.io/log"
+	"cosmossdk.io/math"
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/server"
 
@@ -52,7 +53,8 @@ type JSONRPCBackend struct {
 	svrCtx    *server.Context
 	clientCtx client.Context
 
-	cfg config.JSONRPCConfig
+	cfg           config.JSONRPCConfig
+	gasMultiplier math.LegacyDec
 }
 
 type txQueueItem struct {
@@ -84,6 +86,14 @@ func NewJSONRPCBackend(
 	if cfg.LogCacheSize == 0 {
 		cfg.LogCacheSize = config.DefaultLogCacheSize
 	}
+	if cfg.GasMultiplier == "" {
+		cfg.GasMultiplier = config.DefaultGasMultiplier
+	}
+
+	gasMultiplier, err := math.LegacyNewDecFromStr(cfg.GasMultiplier)
+	if err != nil {
+		return nil, err
+	}
 
 	queuedTxHashes := new(sync.Map)
 	queuedTxs, err := lrucache.NewWithEvict(cfg.QueuedTransactionCap, func(_ string, txCache txQueueItem) {
@@ -118,7 +128,9 @@ func NewJSONRPCBackend(
 		ctx:       ctx,
 		svrCtx:    svrCtx,
 		clientCtx: clientCtx,
-		cfg:       cfg,
+
+		cfg:           cfg,
+		gasMultiplier: gasMultiplier,
 	}
 
 	// start fee fetcher

jsonrpc/backend/gas.go

@@ -90,7 +90,9 @@ func (b *JSONRPCBackend) EstimateGas(args rpctypes.TransactionArgs, blockNrOrHas
 		return hexutil.Uint64(0), err
 	}
 
-	return hexutil.Uint64(gasInfo.GasUsed), nil
+	// apply gas multiplier
+	gasUsed := b.gasMultiplier.MulInt(math.NewIntFromUint64(gasInfo.GasUsed)).TruncateInt().Uint64()
+	return hexutil.Uint64(gasUsed), nil
 }
 
 func (b *JSONRPCBackend) GasPrice() (*hexutil.Big, error) {

jsonrpc/backend/gas_test.go

@@ -84,6 +84,5 @@ func Test_EstimateGas(t *testing.T) {
 		Nonce: nil,
 	}, nil, nil)
 	require.NoError(t, err)
-	require.Greater(t, gasEstimated, uint64(10_000))
-	require.Less(t, uint64(gasEstimated), uint64(finalizeRes.TxResults[1].GasUsed))
+	require.Greater(t, uint64(gasEstimated), uint64(finalizeRes.TxResults[1].GasUsed))
 }

jsonrpc/config/config.go

@@ -42,6 +42,8 @@ const (
 	DefaultFilterTimeout = 5 * time.Minute
 	// DefaultLogCacheSize is the maximum number of cached blocks.
 	DefaultLogCacheSize = 32
+	// DefaultGasMultiplier is the default gas multiplier for the EVM state transition.
+	DefaultGasMultiplier = "1.4"
 )
 
 var (
@@ -67,6 +69,7 @@ const (
 	flagJSONRPCFeeHistoryMaxBlocks  = "json-rpc.fee-history-max-blocks"
 	flagJSONRPCFilterTimeout        = "json-rpc.filter-timeout"
 	flagJSONRPCLogCacheSize         = "json-rpc.log-cache-size"
+	flagJSONRPCGasMultiplier        = "json-rpc.gas-multiplier"
 )
 
 // JSONRPCConfig defines configuration for the EVM RPC server.
@@ -104,6 +107,8 @@ type JSONRPCConfig struct {
 	FilterTimeout time.Duration `mapstructure:"filter-timeout"`
 	// LogCacheSize is the maximum number of cached blocks.
 	LogCacheSize int `mapstructure:"log-cache-size"`
+	// GasMultiplier is the gas multiplier for the EVM state transition.
+	GasMultiplier string `mapstructure:"gas-multiplier"`
 }
 
 // DefaultJSONRPCConfig returns a default configuration for the EVM RPC server.
@@ -132,6 +137,8 @@ func DefaultJSONRPCConfig() JSONRPCConfig {
 		FilterTimeout: DefaultFilterTimeout,
 
 		LogCacheSize: DefaultLogCacheSize,
+
+		GasMultiplier: DefaultGasMultiplier,
 	}
 }
 
@@ -153,6 +160,7 @@ func AddConfigFlags(startCmd *cobra.Command) {
 	startCmd.Flags().Int(flagJSONRPCFeeHistoryMaxBlocks, DefaultFeeHistoryMaxBlocks, "Maximum number of blocks used to lookup the fee history")
 	startCmd.Flags().Duration(flagJSONRPCFilterTimeout, DefaultFilterTimeout, "Duration how long filters stay active")
 	startCmd.Flags().Int(flagJSONRPCLogCacheSize, DefaultLogCacheSize, "Maximum number of cached blocks for the log filter")
+	startCmd.Flags().String(flagJSONRPCGasMultiplier, DefaultGasMultiplier, "Gas multiplier for the EVM state transition")
 }
 
 // GetConfig load config values from the app options
@@ -174,6 +182,7 @@ func GetConfig(appOpts servertypes.AppOptions) JSONRPCConfig {
 		FeeHistoryMaxBlocks:  cast.ToInt(appOpts.Get(flagJSONRPCFeeHistoryMaxBlocks)),
 		FilterTimeout:        cast.ToDuration(appOpts.Get(flagJSONRPCFilterTimeout)),
 		LogCacheSize:         cast.ToInt(appOpts.Get(flagJSONRPCLogCacheSize)),
+		GasMultiplier:        cast.ToString(appOpts.Get(flagJSONRPCGasMultiplier)),
 	}
 }
 
@@ -235,4 +244,7 @@ filter-timeout = "{{ .JSONRPCConfig.FilterTimeout }}"
 
 # LogCacheSize is the maximum number of cached blocks for the log filter.
 log-cache-size = {{ .JSONRPCConfig.LogCacheSize }}
+
+# GasMultiplier is the gas multiplier for the EVM state transition.
+gas-multiplier = "{{ .JSONRPCConfig.GasMultiplier }}"
 `