rpc: configure gas cap (#457)

* rpc: configure gas cap

* c++

* rm old const

* docs

ethereum/rpc/apis.go

@@ -36,7 +36,7 @@ const (
 // GetRPCAPIs returns the list of all APIs
 func GetRPCAPIs(ctx *server.Context, clientCtx client.Context, tmWSClient *rpcclient.WSClient, selectedAPIs []string) []rpc.API {
 	nonceLock := new(types.AddrLocker)
-	evmBackend := backend.NewEVMBackend(ctx.Logger, clientCtx)
+	evmBackend := backend.NewEVMBackend(ctx, ctx.Logger, clientCtx)
 
 	var apis []rpc.API
 	// remove duplicates

ethereum/rpc/backend/backend.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/client/flags"
 	codectypes "github.com/cosmos/cosmos-sdk/codec/types"
+	"github.com/cosmos/cosmos-sdk/server"
 	authtx "github.com/cosmos/cosmos-sdk/x/auth/tx"
 	"github.com/ethereum/go-ethereum/accounts/keystore"
 
@@ -28,6 +29,7 @@ import (
 	ethtypes "github.com/ethereum/go-ethereum/core/types"
 
 	"github.com/tharsis/ethermint/ethereum/rpc/types"
+	"github.com/tharsis/ethermint/server/config"
 	ethermint "github.com/tharsis/ethermint/types"
 	evmtypes "github.com/tharsis/ethermint/x/evm/types"
 )
@@ -48,6 +50,7 @@ type Backend interface {
 	BloomStatus() (uint64, uint64)
 	GetCoinbase() (sdk.AccAddress, error)
 	EstimateGas(args evmtypes.CallArgs, blockNrOptional *types.BlockNumber) (hexutil.Uint64, error)
+	RPCGasCap() uint64
 }
 
 var _ Backend = (*EVMBackend)(nil)
@@ -59,20 +62,28 @@ type EVMBackend struct {
 	queryClient *types.QueryClient // gRPC query client
 	logger      log.Logger
 	chainID     *big.Int
+	cfg         config.Config
 }
 
 // NewEVMBackend creates a new EVMBackend instance
-func NewEVMBackend(logger log.Logger, clientCtx client.Context) *EVMBackend {
+func NewEVMBackend(ctx *server.Context, logger log.Logger, clientCtx client.Context) *EVMBackend {
 	chainID, err := ethermint.ParseChainID(clientCtx.ChainID)
 	if err != nil {
 		panic(err)
 	}
+
+	appConf, err := config.ParseConfig(ctx.Viper)
+	if err != nil {
+		panic(err)
+	}
+
 	return &EVMBackend{
 		ctx:         context.Background(),
 		clientCtx:   clientCtx,
 		queryClient: types.NewQueryClient(clientCtx),
 		logger:      logger.With("module", "evm-backend"),
 		chainID:     chainID,
+		cfg:         *appConf,
 	}
 }
 
@@ -547,7 +558,8 @@ func (e *EVMBackend) EstimateGas(args evmtypes.CallArgs, blockNrOptional *types.
 	if err != nil {
 		return 0, err
 	}
-	req := evmtypes.EthCallRequest{Args: bz, GasCap: ethermint.DefaultRPCGasLimit}
+
+	req := evmtypes.EthCallRequest{Args: bz, GasCap: e.RPCGasCap()}
 
 	// From ContextWithHeight: if the provided height is 0,
 	// it will return an empty context and the gRPC query will use
@@ -581,3 +593,8 @@ func (e *EVMBackend) GetTransactionCount(address common.Address, blockNum types.
 	n := hexutil.Uint64(nonce)
 	return &n, nil
 }
+
+// RPCGasCap is the global gas cap for eth-call variants.
+func (e *EVMBackend) RPCGasCap() uint64 {
+	return e.cfg.JSONRPC.GasCap
+}

ethereum/rpc/backend/utils.go

@@ -12,7 +12,6 @@ import (
 
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/tharsis/ethermint/ethereum/rpc/types"
-	ethermint "github.com/tharsis/ethermint/types"
 	evmtypes "github.com/tharsis/ethermint/x/evm/types"
 )
 
@@ -21,10 +20,8 @@ import (
 func (e *EVMBackend) setTxDefaults(args types.SendTxArgs) (types.SendTxArgs, error) {
 
 	if args.GasPrice == nil {
-		// TODO: Change to either:
-		// - min gas price from context once available through server/daemon, or
-		// - suggest a gas price based on the previous included txs
-		args.GasPrice = (*hexutil.Big)(big.NewInt(ethermint.DefaultGasPrice))
+		// TODO: Suggest a gas price based on the previous included txs
+		args.GasPrice = (*hexutil.Big)(new(big.Int).SetUint64(e.RPCGasCap()))
 	}
 
 	if args.Nonce == nil {

ethereum/rpc/namespaces/eth/api.go

@@ -167,8 +167,7 @@ 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")
-	// TODO: use minimum value defined in config instead of default or implement oracle
-	out := big.NewInt(ethermint.DefaultGasPrice)
+	out := new(big.Int).SetUint64(e.backend.RPCGasCap())
 	return (*hexutil.Big)(out)
 }
 
@@ -438,7 +437,7 @@ func (e *PublicAPI) doCall(
 	if err != nil {
 		return nil, err
 	}
-	req := evmtypes.EthCallRequest{Args: bz, GasCap: ethermint.DefaultRPCGasLimit}
+	req := evmtypes.EthCallRequest{Args: bz, GasCap: e.backend.RPCGasCap()}
 
 	// From ContextWithHeight: if the provided height is 0,
 	// it will return an empty context and the gRPC query will use

ethereum/rpc/namespaces/miner/api.go

@@ -9,7 +9,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/client/flags"
 	"github.com/cosmos/cosmos-sdk/client/tx"
 	"github.com/cosmos/cosmos-sdk/server"
-	"github.com/cosmos/cosmos-sdk/server/config"
+	sdkconfig "github.com/cosmos/cosmos-sdk/server/config"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 
 	authtx "github.com/cosmos/cosmos-sdk/x/auth/tx"
@@ -23,6 +23,7 @@ import (
 
 	"github.com/tharsis/ethermint/ethereum/rpc/backend"
 	rpctypes "github.com/tharsis/ethermint/ethereum/rpc/types"
+	"github.com/tharsis/ethermint/server/config"
 )
 
 // API is the miner prefixed set of APIs in the Miner JSON-RPC spec.
@@ -186,7 +187,7 @@ func (api *API) SetGasPrice(gasPrice hexutil.Big) bool {
 	c := sdk.NewDecCoin(unit, sdk.NewIntFromBigInt(gasPrice.ToInt()))
 
 	appConf.SetMinGasPrices(sdk.DecCoins{c})
-	config.WriteConfigFile(api.ctx.Viper.ConfigFileUsed(), appConf)
+	sdkconfig.WriteConfigFile(api.ctx.Viper.ConfigFileUsed(), appConf)
 	api.logger.Info("Your configuration file was modified. Please RESTART your node.", "gas-price", c.String())
 	return true
 }