rpc: fix gas price (#568)

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

ethereum/rpc/backend/backend.go

@@ -56,6 +56,7 @@ type Backend interface {
 	GetTxByEthHash(txHash common.Hash) (*tmrpctypes.ResultTx, error)
 	EstimateGas(args evmtypes.CallArgs, blockNrOptional *types.BlockNumber) (hexutil.Uint64, error)
 	RPCGasCap() uint64
+	RPCMinGasPrice() int64
 }
 
 var _ Backend = (*EVMBackend)(nil)
@@ -77,10 +78,7 @@ func NewEVMBackend(ctx *server.Context, logger log.Logger, clientCtx client.Cont
 		panic(err)
 	}
 
-	appConf, err := config.ParseConfig(ctx.Viper)
-	if err != nil {
-		panic(err)
-	}
+	appConf := config.GetConfig(ctx.Viper)
 
 	return &EVMBackend{
 		ctx:         context.Background(),
@@ -88,7 +86,7 @@ func NewEVMBackend(ctx *server.Context, logger log.Logger, clientCtx client.Cont
 		queryClient: types.NewQueryClient(clientCtx),
 		logger:      logger.With("module", "evm-backend"),
 		chainID:     chainID,
-		cfg:         *appConf,
+		cfg:         appConf,
 	}
 }
 
@@ -700,3 +698,18 @@ func (e *EVMBackend) GetTransactionCount(address common.Address, blockNum types.
 func (e *EVMBackend) RPCGasCap() uint64 {
 	return e.cfg.JSONRPC.GasCap
 }
+
+// RPCMinGasPrice return the minimum gas price for a transaction.
+func (e *EVMBackend) RPCMinGasPrice() int64 {
+	evmParams, err := e.queryClient.Params(context.Background(), &evmtypes.QueryParamsRequest{})
+	if err == nil {
+		minGasPrice := e.cfg.GetMinGasPrices()
+		for _, coin := range minGasPrice {
+			if coin.Denom == evmParams.Params.EvmDenom {
+				return coin.Amount.TruncateInt64()
+			}
+		}
+	}
+
+	return ethermint.DefaultGasPrice
+}

ethereum/rpc/backend/utils.go

@@ -23,7 +23,7 @@ import (
 func (e *EVMBackend) setTxDefaults(args types.SendTxArgs) (types.SendTxArgs, error) {
 	if args.GasPrice == nil {
 		// TODO: Suggest a gas price based on the previous included txs
-		args.GasPrice = (*hexutil.Big)(new(big.Int).SetUint64(e.RPCGasCap()))
+		args.GasPrice = (*hexutil.Big)(new(big.Int).SetInt64(e.RPCMinGasPrice()))
 	}
 
 	if args.Nonce == nil {

ethereum/rpc/namespaces/eth/api.go

@@ -164,7 +164,7 @@ func (e *PublicAPI) Hashrate() hexutil.Uint64 {
 // GasPrice returns the current gas price based on Ethermint's gas price oracle.
 func (e *PublicAPI) GasPrice() *hexutil.Big {
 	e.logger.Debug("eth_gasPrice")
-	out := new(big.Int).SetUint64(e.backend.RPCGasCap())
+	out := new(big.Int).SetInt64(e.backend.RPCMinGasPrice())
 	return (*hexutil.Big)(out)
 }
 

testutil/network/network.go

@@ -221,6 +221,7 @@ func New(t *testing.T, cfg Config) *Network {
 		appCfg.Telemetry.Enabled = false
 
 		ctx := server.NewDefaultContext()
+
 		tmCfg := ctx.Config
 		tmCfg.Consensus.TimeoutCommit = cfg.TimeoutCommit
 
@@ -359,6 +360,13 @@ func New(t *testing.T, cfg Config) *Network {
 		require.NoError(t, writeFile(fmt.Sprintf("%v.json", nodeDirName), gentxsDir, txBz))
 
 		config.WriteConfigFile(filepath.Join(nodeDir, "config/app.toml"), appCfg)
+		ctx.Viper.AddConfigPath(fmt.Sprintf("%s/config", nodeDir))
+		ctx.Viper.SetConfigName("app")
+		ctx.Viper.SetConfigType("toml")
+		err = ctx.Viper.ReadInConfig()
+		if err != nil {
+			panic(err)
+		}
 
 		clientCtx := client.Context{}.
 			WithKeyringDir(nodeDir).

types/coin.go

@@ -19,6 +19,9 @@ const (
 	// BaseDenomUnit defines the base denomination unit for Photons.
 	// 1 photon = 1x10^{BaseDenomUnit} aphoton
 	BaseDenomUnit = 18
+
+	// DefaultGasPrice is default gas price for evm transactions
+	DefaultGasPrice = 20
 )
 
 // PowerReduction defines the default power reduction value for staking