refactor(execution_deposits_exporter): cache exported deposits by mer…

…kleTreeIndex

backend/pkg/exporter/modules/execution_deposits_exporter.go

@@ -20,6 +20,7 @@ import (
 	"github.com/ethereum/go-ethereum/ethclient"
 	gethrpc "github.com/ethereum/go-ethereum/rpc"
 	"github.com/go-redis/redis/v8"
+	lru "github.com/hashicorp/golang-lru/v2"
 	"golang.org/x/exp/maps"
 
 	"github.com/gobitfly/beaconchain/pkg/commons/contracts/deposit_contract"
@@ -51,6 +52,7 @@ type executionDepositsExporter struct {
 	CurrentHeadBlock                   atomic.Uint64
 	Signer                             gethtypes.Signer
 	DepositMethod                      abi.Method
+	exportedCache                      *lru.Cache[string, bool] // cache for exported deposits by merkle-tree-index
 }
 
 func NewExecutionDepositsExporter(moduleContext ModuleContext) ModuleInterface {
@@ -64,6 +66,12 @@ func NewExecutionDepositsExporter(moduleContext ModuleContext) ModuleInterface {
 }
 
 func (d *executionDepositsExporter) Init() error {
+	exportedCache, err := lru.New[string, bool](2048)
+	if err != nil {
+		log.Fatal(err, "error creating exportedCache", 0)
+	}
+	d.exportedCache = exportedCache
+
 	d.Signer = gethtypes.NewCancunSigner(big.NewInt(0).SetUint64(utils.Config.Chain.ClConfig.DepositChainID))
 
 	d.LastExportedFinalizedBlockRedisKey = fmt.Sprintf("%d:execution_deposits_exporter:last_exported_finalized_block", utils.Config.Chain.ClConfig.DepositChainID)
@@ -311,6 +319,11 @@ func (d *executionDepositsExporter) fetchDeposits(fromBlock, toBlock uint64) (de
 		}
 
 		depositLog := depositLogIterator.Event
+
+		if d.exportedCache.Contains(hexutil.Encode(depositLog.Index)) {
+			continue
+		}
+
 		err = utils.VerifyDepositSignature(&phase0.DepositData{
 			PublicKey:             phase0.BLSPubKey(depositLog.Pubkey),
 			WithdrawalCredentials: depositLog.WithdrawalCredentials,
@@ -490,6 +503,10 @@ func (d *executionDepositsExporter) saveDeposits(depositsToSave []*types.ELDepos
 		return fmt.Errorf("error committing db-tx for execution layer deposits: %w", err)
 	}
 
+	for _, dd := range depositsToSave {
+		d.exportedCache.Add(hexutil.Encode(dd.MerkletreeIndex), true)
+	}
+
 	return nil
 }