Add TTL value for UserOperations (#252)

Author: hazim-j

internal/config/values.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"math/big"
 	"strings"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/gin-gonic/gin"
@@ -20,6 +21,7 @@ type Values struct {
 	SupportedEntryPoints    []common.Address
 	MaxVerificationGas      *big.Int
 	MaxBatchGasLimit        *big.Int
+	MaxOpTTL                time.Duration
 	MaxOpsForUnstakedSender int
 	Beneficiary             string
 
@@ -73,6 +75,7 @@ func GetValues() *Values {
 	viper.SetDefault("erc4337_bundler_supported_entry_points", "0x5FF137D4b0FDCD49DcA30c7CF57E578a026d2789")
 	viper.SetDefault("erc4337_bundler_max_verification_gas", 3000000)
 	viper.SetDefault("erc4337_bundler_max_batch_gas_limit", 25000000)
+	viper.SetDefault("erc4337_bundler_max_op_ttl_seconds", 180)
 	viper.SetDefault("erc4337_bundler_max_ops_for_unstaked_sender", 4)
 	viper.SetDefault("erc4337_bundler_blocks_in_the_future", 25)
 	viper.SetDefault("erc4337_bundler_otel_insecure_mode", false)
@@ -101,6 +104,7 @@ func GetValues() *Values {
 	_ = viper.BindEnv("erc4337_bundler_beneficiary")
 	_ = viper.BindEnv("erc4337_bundler_max_verification_gas")
 	_ = viper.BindEnv("erc4337_bundler_max_batch_gas_limit")
+	_ = viper.BindEnv("erc4337_bundler_max_op_ttl_seconds")
 	_ = viper.BindEnv("erc4337_bundler_max_ops_for_unstaked_sender")
 	_ = viper.BindEnv("erc4337_bundler_eth_builder_url")
 	_ = viper.BindEnv("erc4337_bundler_blocks_in_the_future")
@@ -150,6 +154,7 @@ func GetValues() *Values {
 	beneficiary := viper.GetString("erc4337_bundler_beneficiary")
 	maxVerificationGas := big.NewInt(int64(viper.GetInt("erc4337_bundler_max_verification_gas")))
 	maxBatchGasLimit := big.NewInt(int64(viper.GetInt("erc4337_bundler_max_batch_gas_limit")))
+	maxOpTTL := time.Second * viper.GetDuration("erc4337_bundler_max_op_ttl_seconds")
 	maxOpsForUnstakedSender := viper.GetInt("erc4337_bundler_max_ops_for_unstaked_sender")
 	ethBuilderUrl := viper.GetString("erc4337_bundler_eth_builder_url")
 	blocksInTheFuture := viper.GetInt("erc4337_bundler_blocks_in_the_future")
@@ -168,6 +173,7 @@ func GetValues() *Values {
 		Beneficiary:             beneficiary,
 		MaxVerificationGas:      maxVerificationGas,
 		MaxBatchGasLimit:        maxBatchGasLimit,
+		MaxOpTTL:                maxOpTTL,
 		MaxOpsForUnstakedSender: maxOpsForUnstakedSender,
 		EthBuilderUrl:           ethBuilderUrl,
 		BlocksInTheFuture:       blocksInTheFuture,

internal/start/private.go

@@ -22,6 +22,7 @@ import (
 	"github.com/stackup-wallet/stackup-bundler/pkg/mempool"
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/batch"
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/checks"
+	"github.com/stackup-wallet/stackup-bundler/pkg/modules/expire"
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/gasprice"
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/paymaster"
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/relay"
@@ -107,6 +108,8 @@ func PrivateMode() {
 		conf.MaxOpsForUnstakedSender,
 	)
 
+	exp := expire.New(conf.MaxOpTTL)
+
 	relayer := relay.New(eoa, eth, chain, beneficiary, logr)
 
 	paymaster := paymaster.New(db)
@@ -134,6 +137,7 @@ func PrivateMode() {
 		log.Fatal(err)
 	}
 	b.UseModules(
+		exp.DropExpired(),
 		gasprice.SortByGasPrice(),
 		gasprice.FilterUnderpriced(),
 		batch.SortByNonce(),

internal/start/searcher.go

@@ -24,6 +24,7 @@ import (
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/batch"
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/builder"
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/checks"
+	"github.com/stackup-wallet/stackup-bundler/pkg/modules/expire"
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/gasprice"
 	"github.com/stackup-wallet/stackup-bundler/pkg/modules/paymaster"
 	"github.com/stackup-wallet/stackup-bundler/pkg/signer"
@@ -104,6 +105,9 @@ func SearcherMode() {
 		conf.MaxBatchGasLimit,
 		conf.MaxOpsForUnstakedSender,
 	)
+
+	exp := expire.New(conf.MaxOpTTL)
+
 	// TODO: Create separate go-routine for tracking transactions sent to the block builder.
 	builder := builder.New(eoa, eth, fb, beneficiary, conf.BlocksInTheFuture)
 	paymaster := paymaster.New(db)
@@ -132,6 +136,7 @@ func SearcherMode() {
 		log.Fatal(err)
 	}
 	b.UseModules(
+		exp.DropExpired(),
 		gasprice.SortByGasPrice(),
 		gasprice.FilterUnderpriced(),
 		batch.SortByNonce(),

pkg/modules/expire/expire.go

@@ -0,0 +1,39 @@
+package expire
+
+import (
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/stackup-wallet/stackup-bundler/pkg/modules"
+)
+
+type ExpireHandler struct {
+	seenAt map[common.Hash]time.Time
+	ttl    time.Duration
+}
+
+// New returns an ExpireHandler which contains a BatchHandlerFunc to track and drop UserOperations that have
+// been in the mempool for longer than the TTL duration.
+func New(ttl time.Duration) *ExpireHandler {
+	return &ExpireHandler{
+		seenAt: make(map[common.Hash]time.Time),
+		ttl:    ttl,
+	}
+}
+
+// DropExpired returns a BatchHandlerFunc that will drop UserOperations from the mempool if it has been around
+// for longer than the TTL duration.
+func (e *ExpireHandler) DropExpired() modules.BatchHandlerFunc {
+	return func(ctx *modules.BatchHandlerCtx) error {
+		end := len(ctx.Batch) - 1
+		for i := end; i >= 0; i-- {
+			hash := ctx.Batch[i].GetUserOpHash(ctx.EntryPoint, ctx.ChainID)
+			if seenAt, ok := e.seenAt[hash]; !ok {
+				e.seenAt[hash] = time.Now()
+			} else if seenAt.Add(e.ttl).Before(time.Now()) {
+				ctx.MarkOpIndexForRemoval(i)
+			}
+		}
+		return nil
+	}
+}

pkg/modules/expire/expire_test.go

@@ -0,0 +1,45 @@
+package expire
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/stackup-wallet/stackup-bundler/internal/testutils"
+	"github.com/stackup-wallet/stackup-bundler/pkg/modules"
+	"github.com/stackup-wallet/stackup-bundler/pkg/userop"
+)
+
+// TestDropExpired calls (*ExpireHandler).DropExpired and verifies that it marks old UserOperations for
+// pending removal.
+func TestDropExpired(t *testing.T) {
+	exp := New(time.Second * 30)
+	op1 := testutils.MockValidInitUserOp()
+	op2 := testutils.MockValidInitUserOp()
+	op2.CallData = common.Hex2Bytes("0xdead")
+	exp.seenAt = map[common.Hash]time.Time{
+		op1.GetUserOpHash(testutils.ValidAddress1, common.Big1): time.Now().Add(time.Second * -45),
+		op2.GetUserOpHash(testutils.ValidAddress1, common.Big1): time.Now().Add(time.Second * -15),
+	}
+
+	ctx := modules.NewBatchHandlerContext(
+		[]*userop.UserOperation{op1, op2},
+		testutils.ValidAddress1,
+		testutils.ChainID,
+		nil,
+		nil,
+		nil,
+	)
+	if err := exp.DropExpired()(ctx); err != nil {
+		t.Fatalf("got %v, want nil", err)
+	} else if len(ctx.Batch) != 1 {
+		t.Fatalf("got batch length %d, want 1", len(ctx.Batch))
+	} else if len(ctx.PendingRemoval) != 1 {
+		t.Fatalf("got pending removal length %d, want 1", len(ctx.Batch))
+	} else if !testutils.IsOpsEqual(ctx.Batch[0], op2) {
+		t.Fatal("incorrect batch: Dropped legit op")
+	} else if !testutils.IsOpsEqual(ctx.PendingRemoval[0], op1) {
+		t.Fatal("incorrect pending removal: Didn't drop bad op")
+	}
+
+}