Merge pull request #61 from renproject/revert/cosmos-gas-estimation

chain/cosmos: revert gas estimation change

chain/cosmos/gas.go

@@ -7,37 +7,26 @@ import (
 	"github.com/renproject/pack"
 )
 
-const (
-	microToPico = 1000000
-)
-
-// A GasEstimator returns the gas price that is needed in order to confirm
-// transactions with an estimated maximum delay of one block. As of now, Cosmos
-// compatible chains do not support transaction prioritisation in the mempool.
-// Hence we use constant gas price set in the micro-denomination (1e-6) of the
-// underlying token. However, the gas price as returned by the gas estimation
-// API is a 32-byte unsigned integer that represents the gas price in the
-// pico-denomination (1e-12).
+// A GasEstimator returns the gas-per-byte that is needed in order to confirm
+// transactions with an estimated maximum delay of one block. In distributed
+// networks that collectively build, sign, and submit transactions, it is
+// important that all nodes in the network have reached consensus on the
+// gas-per-byte.
 type GasEstimator struct {
-	gasPrice float64
+	gasPerByte pack.U256
 }
 
 // NewGasEstimator returns a simple gas estimator that always returns the same
 // amount of gas-per-byte.
-func NewGasEstimator(gasPrice float64) gas.Estimator {
+func NewGasEstimator(gasPerByte pack.U256) gas.Estimator {
 	return &GasEstimator{
-		gasPrice: gasPrice,
+		gasPerByte: gasPerByte,
 	}
 }
 
 // EstimateGas returns gas required per byte for Cosmos-compatible chains. This
 // value is used for both the price and cap, because Cosmos-compatible chains do
-// not have a distinct concept of cap. As of now, Cosmos compatible chains do
-// not support transaction prioritisation in the mempool. Hence we use constant
-// gas price set in the micro-denomination (1e-6) of the underlying token.
-// However, the gas price as returned by the gas estimation API is a 32-byte
-// unsigned integer representing gas price in the pico-denomination (1e-12).
+// not have a distinct concept of cap.
 func (gasEstimator *GasEstimator) EstimateGas(ctx context.Context) (pack.U256, pack.U256, error) {
-	gasPrice := pack.NewU256FromUint64(uint64(gasEstimator.gasPrice * microToPico))
-	return gasPrice, gasPrice, nil
+	return gasEstimator.gasPerByte, gasEstimator.gasPerByte, nil
 }

chain/cosmos/gas_test.go

@@ -2,9 +2,7 @@ package cosmos_test
 
 import (
 	"context"
-	"math/rand"
 	"testing/quick"
-	"time"
 
 	"github.com/renproject/multichain/chain/cosmos"
 	"github.com/renproject/pack"
@@ -14,16 +12,13 @@ import (
 )
 
 var _ = Describe("Gas", func() {
-	r := rand.New(rand.NewSource(time.Now().UnixNano()))
 	Context("when estimating gas parameters", func() {
 		It("should work", func() {
-			f := func() bool {
-				gasPriceMicro := r.Float64()
-				gasEstimator := cosmos.NewGasEstimator(gasPriceMicro)
-				gasPricePico, _, err := gasEstimator.EstimateGas(context.Background())
+			f := func(gasPerByte pack.U256) bool {
+				gasEstimator := cosmos.NewGasEstimator(gasPerByte)
+				gasPrice, _, err := gasEstimator.EstimateGas(context.Background())
 				Expect(err).NotTo(HaveOccurred())
-				expectedGasPrice := pack.NewU256FromUint64(uint64(gasPriceMicro * 1000000))
-				Expect(gasPricePico).To(Equal(expectedGasPrice))
+				Expect(gasPrice).To(Equal(gasPerByte))
 				return true
 			}
 			Expect(quick.Check(f, nil)).To(Succeed())

chain/cosmos/tx.go

@@ -63,8 +63,7 @@ func NewTxBuilder(options TxBuilderOptions, client *Client) account.TxBuilder {
 
 // BuildTx consumes a list of MsgSend to build and return a cosmos transaction.
 // This transaction is unsigned, and must be signed before submitting to the
-// cosmos chain. Note that the gas price is represented in the pico-denomination
-// (1e-12) and must be converted back to the micro-denomination (1e-6).
+// cosmos chain.
 func (builder txBuilder) BuildTx(ctx context.Context, from, to address.Address, value, nonce, gasLimit, gasPrice, gasCap pack.U256, payload pack.Bytes) (account.Tx, error) {
 	types.GetConfig().SetBech32PrefixForAccount(builder.client.hrp, builder.client.hrp+"pub")
 
@@ -91,7 +90,7 @@ func (builder txBuilder) BuildTx(ctx context.Context, from, to address.Address,
 
 	fees := Coins{Coin{
 		Denom:  builder.client.opts.CoinDenom,
-		Amount: pack.NewU64(gasPrice.Mul(gasLimit).Div(pack.NewU256FromUint64(uint64(microToPico))).Int().Uint64()),
+		Amount: pack.NewU64(gasPrice.Mul(gasLimit).Int().Uint64()),
 	}}
 
 	accountNumber, err := builder.client.AccountNumber(ctx, from)

go.mod

@@ -5,7 +5,6 @@ go 1.14
 require (
 	github.com/btcsuite/btcd v0.21.0-beta
 	github.com/btcsuite/btcutil v1.0.2
-	github.com/centrifuge/go-substrate-rpc-client v1.1.0
 	github.com/codahale/blake2 v0.0.0-20150924215134-8d10d0420cbf
 	github.com/cosmos/cosmos-sdk v0.39.1
 	github.com/ethereum/go-ethereum v1.9.20