Update GetGasPrice RPC endpoint with global MinGasPrice

CHANGELOG.md

@@ -44,6 +44,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 - (rpc) [tharsis#1081](https://github.com/tharsis/ethermint/pull/1081) Deduplicate some json-rpc logic codes, cleanup several dead functions.
 - (ante) [tharsis#1062](https://github.com/tharsis/ethermint/pull/1062) Emit event of eth tx hash in ante handler to support query failed transactions.
 - (analytics) [tharsis#1106](https://github.com/tharsis/ethermint/pull/1106) Update telemetry to Ethermint modules.
+- (rpc) [tharsis#1108](https://github.com/tharsis/ethermint/pull/1108) Update GetGasPrice RPC endpoint with global `MinGasPrice`
 
 ### Improvements
 

rpc/backend/backend.go

@@ -69,6 +69,7 @@ type EVMBackend interface {
  GetTxByTxIndex(height int64, txIndex uint) (*tmrpctypes.ResultTx, error)
  EstimateGas(args evmtypes.TransactionArgs, blockNrOptional *types.BlockNumber) (hexutil.Uint64, error)
  BaseFee(height int64) (*big.Int, error)
+ GlobalMinGasPrice() (sdk.Dec, error)
 
  // Fee API
  FeeHistory(blockCount rpc.DecimalOrHex, lastBlock rpc.BlockNumber, rewardPercentiles []float64) (*types.FeeHistoryResult, error)

rpc/backend/evm_backend.go

@@ -818,6 +818,15 @@ func (b *Backend) BaseFee(height int64) (*big.Int, error) {
  return res.BaseFee.BigInt(), nil
 }
 
+// GlobalMinGasPrice returns MinGasPrice param from FeeMarket
+func (b *Backend) GlobalMinGasPrice() (sdk.Dec, error) {
+ res, err := b.queryClient.FeeMarket.Params(b.ctx, &feemarkettypes.QueryParamsRequest{})
+ if err != nil {
+ return sdk.ZeroDec(), err
+ }
+ return res.Params.MinGasPrice, nil
+}
+
 // FeeHistory returns data relevant for fee estimation based on the specified range of blocks.
 func (b *Backend) FeeHistory(
  userBlockCount rpc.DecimalOrHex, // number blocks to fetch, maximum is 100

rpc/namespaces/ethereum/eth/api.go

@@ -211,6 +211,16 @@ func (e *PublicAPI) GasPrice() (*hexutil.Big, error) {
  result = big.NewInt(e.backend.RPCMinGasPrice())
  }
 
+ // return at least GlobalMinGasPrice from FeeMarket module
+ minGasPrice, err := e.backend.GlobalMinGasPrice()
+ if err != nil {
+ return nil, err
+ }
+ minGasPriceInt := minGasPrice.BigInt()
+ if result.Cmp(minGasPriceInt) < 0 {
+ result = minGasPriceInt
+ }
+
  return (*hexutil.Big)(result), nil
 }