[CCIP-3376] move interceptor implementation under relay/evm

core/services/relay/evm/interceptors/mantle/interceptor.go

@@ -0,0 +1,80 @@
+package mantle
+
+import (
+	"context"
+	"fmt"
+	"math/big"
+	"strings"
+	"time"
+
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/common"
+
+	evmClient "github.com/smartcontractkit/chainlink/v2/core/chains/evm/client"
+	"github.com/smartcontractkit/chainlink/v2/core/chains/evm/gas/rollups"
+)
+
+const (
+	// tokenRatio is not volatile and can be requested not often.
+	tokenRatioUpdateInterval = 60 * time.Minute
+	// tokenRatio fetches the tokenRatio used for Mantle's gas price calculation
+	tokenRatioMethod          = "tokenRatio"
+	mantleTokenRatioAbiString = `[{"inputs":[],"name":"tokenRatio","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"}]`
+)
+
+type Interceptor struct {
+	client               evmClient.Client
+	tokenRatioCallData   []byte
+	tokenRatio           *big.Int
+	tokenRatioLastUpdate time.Time
+}
+
+func NewInterceptor(_ context.Context, client evmClient.Client) (*Interceptor, error) {
+	// Encode calldata for tokenRatio method
+	tokenRatioMethodAbi, err := abi.JSON(strings.NewReader(mantleTokenRatioAbiString))
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse GasPriceOracle %s() method ABI for Mantle; %v", tokenRatioMethod, err)
+	}
+	tokenRatioCallData, err := tokenRatioMethodAbi.Pack(tokenRatioMethod)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse GasPriceOracle %s() calldata for Mantle; %v", tokenRatioMethod, err)
+	}
+
+	return &Interceptor{
+		client:             client,
+		tokenRatioCallData: tokenRatioCallData,
+	}, nil
+}
+
+// ModifyGasPriceComponents returns modified gasPrice.
+func (i *Interceptor) ModifyGasPriceComponents(ctx context.Context, execGasPrice, daGasPrice *big.Int) (*big.Int, *big.Int, error) {
+	if time.Since(i.tokenRatioLastUpdate) > tokenRatioUpdateInterval {
+		mantleTokenRatio, err := i.getMantleTokenRatio(ctx)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		i.tokenRatio, i.tokenRatioLastUpdate = mantleTokenRatio, time.Now()
+	}
+
+	// multiply daGasPrice and execGas price by tokenRatio
+	newExecGasPrice := new(big.Int).Mul(execGasPrice, i.tokenRatio)
+	newDAGasPrice := new(big.Int).Mul(daGasPrice, i.tokenRatio)
+	return newExecGasPrice, newDAGasPrice, nil
+}
+
+// getMantleTokenRatio Requests and returns a token ratio value for the Mantle chain.
+func (i *Interceptor) getMantleTokenRatio(ctx context.Context) (*big.Int, error) {
+	precompile := common.HexToAddress(rollups.OPGasOracleAddress)
+	tokenRatio, err := i.client.CallContract(ctx, ethereum.CallMsg{
+		To:   &precompile,
+		Data: i.tokenRatioCallData,
+	}, nil)
+
+	if err != nil {
+		return nil, fmt.Errorf("getMantleTokenRatio call failed: %w", err)
+	}
+
+	return new(big.Int).SetBytes(tokenRatio), nil
+}

core/services/relay/evm/interceptors/mantle/interceptor_test.go

@@ -0,0 +1,96 @@
+package mantle
+
+import (
+	"context"
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
+
+	"github.com/smartcontractkit/chainlink/v2/core/chains/evm/client/mocks"
+)
+
+func TestInterceptor(t *testing.T) {
+	ethClient := mocks.NewClient(t)
+	ctx := context.Background()
+
+	tokenRatio := big.NewInt(10)
+	interceptor, err := NewInterceptor(ctx, ethClient)
+	require.NoError(t, err)
+
+	// request token ratio
+	ethClient.On("CallContract", ctx, mock.IsType(ethereum.CallMsg{}), mock.IsType(&big.Int{})).
+		Return(common.BigToHash(tokenRatio).Bytes(), nil).Once()
+
+	modExecGasPrice, modDAGasPrice, err := interceptor.ModifyGasPriceComponents(ctx, big.NewInt(1), big.NewInt(1))
+	require.NoError(t, err)
+	require.Equal(t, int64(10), modExecGasPrice.Int64())
+	require.Equal(t, int64(10), modDAGasPrice.Int64())
+
+	// second call won't invoke eth client
+	modExecGasPrice, modDAGasPrice, err = interceptor.ModifyGasPriceComponents(ctx, big.NewInt(2), big.NewInt(1))
+	require.NoError(t, err)
+	require.Equal(t, int64(20), modExecGasPrice.Int64())
+	require.Equal(t, int64(10), modDAGasPrice.Int64())
+}
+
+func TestModifyGasPriceComponents(t *testing.T) {
+	testCases := map[string]struct {
+		execGasPrice       *big.Int
+		daGasPrice         *big.Int
+		tokenRatio         *big.Int
+		resultExecGasPrice *big.Int
+		resultDAGasPrice   *big.Int
+	}{
+		"regular": {
+			execGasPrice:       big.NewInt(1000),
+			daGasPrice:         big.NewInt(100),
+			resultExecGasPrice: big.NewInt(2000),
+			resultDAGasPrice:   big.NewInt(200),
+			tokenRatio:         big.NewInt(2),
+		},
+		"zero DAGasPrice": {
+			execGasPrice:       big.NewInt(1000),
+			daGasPrice:         big.NewInt(0),
+			resultExecGasPrice: big.NewInt(5000),
+			resultDAGasPrice:   big.NewInt(0),
+			tokenRatio:         big.NewInt(5),
+		},
+		"zero ExecGasPrice": {
+			execGasPrice:       big.NewInt(0),
+			daGasPrice:         big.NewInt(10),
+			resultExecGasPrice: big.NewInt(0),
+			resultDAGasPrice:   big.NewInt(50),
+			tokenRatio:         big.NewInt(5),
+		},
+		"zero token ratio": {
+			execGasPrice:       big.NewInt(15),
+			daGasPrice:         big.NewInt(10),
+			resultExecGasPrice: big.NewInt(0),
+			resultDAGasPrice:   big.NewInt(0),
+			tokenRatio:         big.NewInt(0),
+		},
+	}
+
+	for tcName, tc := range testCases {
+		t.Run(tcName, func(t *testing.T) {
+			ethClient := mocks.NewClient(t)
+			ctx := context.Background()
+
+			interceptor, err := NewInterceptor(ctx, ethClient)
+			require.NoError(t, err)
+
+			// request token ratio
+			ethClient.On("CallContract", ctx, mock.IsType(ethereum.CallMsg{}), mock.IsType(&big.Int{})).
+				Return(common.BigToHash(tc.tokenRatio).Bytes(), nil).Once()
+
+			modExecGasPrice, modDAGasPrice, err := interceptor.ModifyGasPriceComponents(ctx, tc.execGasPrice, tc.daGasPrice)
+			require.NoError(t, err)
+			require.Equal(t, tc.resultExecGasPrice.Int64(), modExecGasPrice.Int64())
+			require.Equal(t, tc.resultDAGasPrice.Int64(), modDAGasPrice.Int64())
+		})
+	}
+}