From aca0684e231685cd1f1f9105ae93f93b335c1276 Mon Sep 17 00:00:00 2001
From: Conner Fromknecht <conner@alum.mit.edu>
Date: Tue, 8 Mar 2022 11:28:29 -0800
Subject: [PATCH] feat: extract gas limit estimation to driver, add 20% buffer

On mainnet we are seeing out of exceptions with some frequency. In all
of these cases it appears we are very, very close to being successful.
This commit extracts the internal calls performed by RawTransact into
the driver and then adds a buffer to limit the possibility of losing
money on the reverting transactions, since these very large transactions
are costly especially in the current fee market.
---
 .changeset/fair-bees-promise.md               |  5 ++
 .../drivers/sequencer/driver.go               | 65 +++++++++++++------
 2 files changed, 50 insertions(+), 20 deletions(-)
 create mode 100644 .changeset/fair-bees-promise.md

diff --git a/.changeset/fair-bees-promise.md b/.changeset/fair-bees-promise.md
new file mode 100644
index 0000000000000..243fbb7227dd5
--- /dev/null
+++ b/.changeset/fair-bees-promise.md
@@ -0,0 +1,5 @@
+---
+'@eth-optimism/batch-submitter-service': patch
+---
+
+Add 20% buffer to gas estimation on tx-batch submission to prevent OOG reverts
diff --git a/go/batch-submitter/drivers/sequencer/driver.go b/go/batch-submitter/drivers/sequencer/driver.go
index 0c5e7a8b74402..e9133d1ab290f 100644
--- a/go/batch-submitter/drivers/sequencer/driver.go
+++ b/go/batch-submitter/drivers/sequencer/driver.go
@@ -12,6 +12,7 @@ import (
 	"github.com/ethereum-optimism/optimism/go/bss-core/metrics"
 	"github.com/ethereum-optimism/optimism/go/bss-core/txmgr"
 	l2ethclient "github.com/ethereum-optimism/optimism/l2geth/ethclient"
+	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/accounts/abi"
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
@@ -267,6 +268,46 @@ func (d *Driver) UpdateGasPrice(
 	tx *types.Transaction,
 ) (*types.Transaction, error) {
 
+	gasTipCap, err := d.cfg.L1Client.SuggestGasTipCap(ctx)
+	if err != nil {
+		// If the transaction failed because the backend does not support
+		// eth_maxPriorityFeePerGas, fallback to using the default constant.
+		// Currently Alchemy is the only backend provider that exposes this
+		// method, so in the event their API is unreachable we can fallback to a
+		// degraded mode of operation. This also applies to our test
+		// environments, as hardhat doesn't support the query either.
+		if !drivers.IsMaxPriorityFeePerGasNotFoundError(err) {
+			return nil, err
+		}
+
+		log.Warn(d.cfg.Name + " eth_maxPriorityFeePerGas is unsupported " +
+			"by current backend, using fallback gasTipCap")
+		gasTipCap = drivers.FallbackGasTipCap
+	}
+
+	header, err := d.cfg.L1Client.HeaderByNumber(ctx, nil)
+	if err != nil {
+		return nil, err
+	}
+	gasFeeCap := txmgr.CalcGasFeeCap(header.BaseFee, gasTipCap)
+
+	// The estimated gas limits performed by RawTransact fail semi-regularly
+	// with out of gas exceptions. To remedy this we extract the internal calls
+	// to perform gas price/gas limit estimation here and add a buffer to
+	// account for any network variability.
+	gasLimit, err := d.cfg.L1Client.EstimateGas(ctx, ethereum.CallMsg{
+		From:      d.walletAddr,
+		To:        &d.cfg.CTCAddr,
+		GasPrice:  nil,
+		GasTipCap: gasTipCap,
+		GasFeeCap: gasFeeCap,
+		Value:     nil,
+		Data:      tx.Data(),
+	})
+	if err != nil {
+		return nil, err
+	}
+
 	opts, err := bind.NewKeyedTransactorWithChainID(
 		d.cfg.PrivKey, d.cfg.ChainID,
 	)
@@ -275,28 +316,12 @@ func (d *Driver) UpdateGasPrice(
 	}
 	opts.Context = ctx
 	opts.Nonce = new(big.Int).SetUint64(tx.Nonce())
+	opts.GasTipCap = gasTipCap
+	opts.GasFeeCap = gasFeeCap
+	opts.GasLimit = 6 * gasLimit / 5 // add 20% buffer to gas limit
 	opts.NoSend = true
 
-	finalTx, err := d.rawCtcContract.RawTransact(opts, tx.Data())
-	switch {
-	case err == nil:
-		return finalTx, nil
-
-	// If the transaction failed because the backend does not support
-	// eth_maxPriorityFeePerGas, fallback to using the default constant.
-	// Currently Alchemy is the only backend provider that exposes this method,
-	// so in the event their API is unreachable we can fallback to a degraded
-	// mode of operation. This also applies to our test environments, as hardhat
-	// doesn't support the query either.
-	case drivers.IsMaxPriorityFeePerGasNotFoundError(err):
-		log.Warn(d.cfg.Name + " eth_maxPriorityFeePerGas is unsupported " +
-			"by current backend, using fallback gasTipCap")
-		opts.GasTipCap = drivers.FallbackGasTipCap
-		return d.rawCtcContract.RawTransact(opts, tx.Data())
-
-	default:
-		return nil, err
-	}
+	return d.rawCtcContract.RawTransact(opts, tx.Data())
 }
 
 // SendTransaction injects a signed transaction into the pending pool for