From 773331bebb509ef66f3a9aab51a8927432e11dc3 Mon Sep 17 00:00:00 2001
From: jeff <113397187+cyberhorsey@users.noreply.github.com>
Date: Tue, 20 Jun 2023 15:35:41 -0700
Subject: [PATCH] feat(relayer): use gas tip cap if available (#14024)

---
 packages/relayer/message/errors.go          | 28 +++++++++++++++++++++
 packages/relayer/message/process_message.go | 19 ++++++++++----
 packages/relayer/message/processor.go       |  1 +
 packages/relayer/mock/eth_client.go         |  4 +++
 4 files changed, 47 insertions(+), 5 deletions(-)
 create mode 100644 packages/relayer/message/errors.go

diff --git a/packages/relayer/message/errors.go b/packages/relayer/message/errors.go
new file mode 100644
index 00000000000..0bf2d406aeb
--- /dev/null
+++ b/packages/relayer/message/errors.go
@@ -0,0 +1,28 @@
+package message
+
+import (
+	"math/big"
+	"strings"
+
+	"github.com/pkg/errors"
+)
+
+var (
+	//lint:ignore ST1005 allow `errMaxPriorityFeePerGasNotFound` to be capitalized.
+	errMaxPriorityFeePerGasNotFound = errors.New(
+		"Method eth_maxPriorityFeePerGas not found",
+	)
+
+	// FallbackGasTipCap is the default fallback gasTipCap used when we are
+	// unable to query an L1 backend for a suggested gasTipCap.
+	FallbackGasTipCap = big.NewInt(1500000000)
+)
+
+// IsMaxPriorityFeePerGasNotFoundError returns true if the provided error
+// signals that the backend does not support the eth_maxPrirorityFeePerGas
+// method. In this case, the caller should fallback to using the constant above.
+func IsMaxPriorityFeePerGasNotFoundError(err error) bool {
+	return strings.Contains(
+		err.Error(), errMaxPriorityFeePerGasNotFound.Error(),
+	)
+}
diff --git a/packages/relayer/message/process_message.go b/packages/relayer/message/process_message.go
index 84671a88930..b6b426fcb55 100644
--- a/packages/relayer/message/process_message.go
+++ b/packages/relayer/message/process_message.go
@@ -100,7 +100,7 @@ func (p *Processor) ProcessMessage(
 
 	relayer.EventsProcessed.Inc()
 
-	ctx, cancel := context.WithTimeout(ctx, 3*time.Minute)
+	ctx, cancel := context.WithTimeout(ctx, 4*time.Minute)
 
 	defer cancel()
 
@@ -205,12 +205,21 @@ func (p *Processor) sendProcessMessageCall(
 		}
 	}
 
-	gasPrice, err := p.destEthClient.SuggestGasPrice(context.Background())
+	gasTipCap, err := p.destEthClient.SuggestGasTipCap(ctx)
 	if err != nil {
-		return nil, errors.Wrap(err, "p.destBridge.SuggestGasPrice")
-	}
+		if IsMaxPriorityFeePerGasNotFoundError(err) {
+			auth.GasTipCap = FallbackGasTipCap
+		} else {
+			gasPrice, err := p.destEthClient.SuggestGasPrice(context.Background())
+			if err != nil {
+				return nil, errors.Wrap(err, "p.destBridge.SuggestGasPrice")
+			}
 
-	auth.GasPrice = gasPrice
+			auth.GasPrice = gasPrice
+		}
+	} else {
+		auth.GasTipCap = gasTipCap
+	}
 
 	if bool(p.profitableOnly) {
 		profitable, err := p.isProfitable(ctx, event.Message, cost)
diff --git a/packages/relayer/message/processor.go b/packages/relayer/message/processor.go
index 11a918bb06d..4eaddd7b5f6 100644
--- a/packages/relayer/message/processor.go
+++ b/packages/relayer/message/processor.go
@@ -19,6 +19,7 @@ type ethClient interface {
 	BlockNumber(ctx context.Context) (uint64, error)
 	HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
 	SuggestGasPrice(ctx context.Context) (*big.Int, error)
+	SuggestGasTipCap(ctx context.Context) (*big.Int, error)
 }
 
 type Processor struct {
diff --git a/packages/relayer/mock/eth_client.go b/packages/relayer/mock/eth_client.go
index 3e598886d20..774b36e8858 100644
--- a/packages/relayer/mock/eth_client.go
+++ b/packages/relayer/mock/eth_client.go
@@ -29,6 +29,10 @@ func (c *EthClient) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
 	return big.NewInt(100), nil
 }
 
+func (c *EthClient) SuggestGasTipCap(ctx context.Context) (*big.Int, error) {
+	return big.NewInt(100), nil
+}
+
 func (c *EthClient) ChainID(ctx context.Context) (*big.Int, error) {
 	return MockChainID, nil
 }