indexer: Don't spam the backend (#2441)

.changeset/serious-tables-jam.md

+---
+'@eth-optimism/indexer': patch
+---
+
+Don't spam the backend

go/indexer/indexer.go

@@ -9,6 +9,8 @@ import (
 	"strconv"
 	"time"
 
+	l2rpc "github.com/ethereum-optimism/optimism/l2geth/rpc"
+
 	"github.com/ethereum-optimism/optimism/go/indexer/metrics"
 	"github.com/ethereum-optimism/optimism/go/indexer/server"
 	"github.com/rs/cors"
@@ -128,7 +130,7 @@ func NewIndexer(cfg Config, gitVersion string) (*Indexer, error) {
 		return nil, err
 	}
 
-	l2Client, err := dialL2EthClientWithTimeout(ctx, cfg.L2EthRpc)
+	l2Client, l2RPC, err := dialL2EthClientWithTimeout(ctx, cfg.L2EthRpc)
 	if err != nil {
 		return nil, err
 	}
@@ -180,6 +182,7 @@ func NewIndexer(cfg Config, gitVersion string) (*Indexer, error) {
 	l2IndexingService, err := l2.NewService(l2.ServiceConfig{
 		Context:            ctx,
 		Metrics:            m,
+		L2RPC:              l2RPC,
 		L2Client:           l2Client,
 		DB:                 db,
 		ConfDepth:          cfg.ConfDepth,
@@ -277,12 +280,17 @@ func dialL1EthClientWithTimeout(ctx context.Context, url string) (
 // provided URL. If the dial doesn't complete within defaultDialTimeout seconds,
 // this method will return an error.
 func dialL2EthClientWithTimeout(ctx context.Context, url string) (
-	*l2ethclient.Client, error) {
+	*l2ethclient.Client, *l2rpc.Client, error) {
 
 	ctxt, cancel := context.WithTimeout(ctx, defaultDialTimeout)
 	defer cancel()
 
-	return l2ethclient.DialContext(ctxt, url)
+	rpc, err := l2rpc.DialContext(ctxt, url)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return l2ethclient.NewClient(rpc), rpc, nil
 }
 
 // traceRateToFloat64 converts a time.Duration into a valid float64 for the

go/indexer/services/l1/confirmed_headers.go

@@ -5,10 +5,10 @@ import (
 	"encoding/json"
 	"errors"
 	"math/big"
-	"sync"
 	"time"
 
-	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum-optimism/optimism/go/indexer/services/util"
+
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -17,9 +17,9 @@ import (
 )
 
 const (
-	DefaultConnectionTimeout        = 20 * time.Second
+	DefaultConnectionTimeout        = 30 * time.Second
 	DefaultConfDepth         uint64 = 20
-	DefaultMaxBatchSize      uint64 = 100
+	DefaultMaxBatchSize             = 100
 )
 
 type NewHeader struct {
@@ -128,24 +128,34 @@ type ConfirmedHeaderSelector struct {
 	cfg HeaderSelectorConfig
 }
 
-func toBlockNumArg(number *big.Int) string {
-	if number == nil {
-		return "latest"
+func HeadersByRange(ctx context.Context, client *rpc.Client, startHeight uint64, count int) ([]*NewHeader, error) {
+	height := startHeight
+	batchElems := make([]rpc.BatchElem, count)
+	for i := 0; i < count; i++ {
+		batchElems[i] = rpc.BatchElem{
+			Method: "eth_getBlockByNumber",
+			Args: []interface{}{
+				util.ToBlockNumArg(new(big.Int).SetUint64(height + uint64(i))),
+				false,
+			},
+			Result: new(NewHeader),
+			Error:  nil,
 		}
-	pending := big.NewInt(-1)
-	if number.Cmp(pending) == 0 {
-		return "pending"
 	}
-	return hexutil.EncodeBig(number)
-}
 
-func HeaderByNumber(ctx context.Context, client *rpc.Client, height *big.Int) (*NewHeader, error) {
-	var head *NewHeader
-	err := client.CallContext(ctx, &head, "eth_getBlockByNumber", toBlockNumArg(height), false)
-	if err == nil && head == nil {
-		err = ethereum.NotFound
+	if err := client.BatchCallContext(ctx, batchElems); err != nil {
+		return nil, err
+	}
+
+	out := make([]*NewHeader, count)
+	for i := 0; i < len(batchElems); i++ {
+		if batchElems[i].Error != nil {
+			return nil, batchElems[i].Error
+		}
+		out[i] = batchElems[i].Result.(*NewHeader)
 	}
-	return head, err
+
+	return out, nil
 }
 
 func (f *ConfirmedHeaderSelector) NewHead(
@@ -153,7 +163,7 @@ func (f *ConfirmedHeaderSelector) NewHead(
 	lowest uint64,
 	header *types.Header,
 	client *rpc.Client,
-) []*NewHeader {
+) ([]*NewHeader, error) {
 
 	number := header.Number.Uint64()
 	blockHash := header.Hash
@@ -161,14 +171,14 @@ func (f *ConfirmedHeaderSelector) NewHead(
 	logger.Info("New block", "block", number, "hash", blockHash)
 
 	if number < f.cfg.ConfDepth {
-		return nil
+		return nil, nil
 	}
 	endHeight := number - f.cfg.ConfDepth + 1
 
 	minNextHeight := lowest + f.cfg.ConfDepth
 	if minNextHeight > number {
 		log.Info("Fork block ", "block", number, "hash", blockHash)
-		return nil
+		return nil, nil
 	}
 	startHeight := lowest + 1
 
@@ -177,34 +187,35 @@ func (f *ConfirmedHeaderSelector) NewHead(
 		endHeight = startHeight + f.cfg.MaxBatchSize - 1
 	}
 
-	nHeaders := endHeight - startHeight + 1
+	nHeaders := int(endHeight - startHeight + 1)
 	if nHeaders > 1 {
-		logger.Info("Loading block batch ",
+		logger.Info("Loading blocks",
 			"startHeight", startHeight, "endHeight", endHeight)
 	}
 
-	headers := make([]*NewHeader, nHeaders)
-	var wg sync.WaitGroup
-	for i := uint64(0); i < nHeaders; i++ {
-		wg.Add(1)
-		go func(ii uint64) {
-			defer wg.Done()
+	headers := make([]*NewHeader, 0)
+	height := startHeight
+	left := nHeaders - len(headers)
+	for left > 0 {
+		count := DefaultMaxBatchSize
+		if count > left {
+			count = left
+		}
 
-			ctxt, cancel := context.WithTimeout(ctx, DefaultConnectionTimeout)
-			defer cancel()
+		logger.Info("Loading block batch",
+			"height", height, "count", count)
 
-			height := startHeight + ii
-			bigHeight := new(big.Int).SetUint64(height)
-			header, err := HeaderByNumber(ctxt, client, bigHeight)
+		ctxt, cancel := context.WithTimeout(ctx, DefaultConnectionTimeout)
+		fetched, err := HeadersByRange(ctxt, client, height, count)
+		cancel()
 		if err != nil {
-				log.Error("Unable to load block ", "block", height, "err", err)
-				return
+			return nil, err
 		}
 
-			headers[ii] = header
-		}(i)
+		headers = append(headers, fetched...)
+		left = nHeaders - len(headers)
+		height += uint64(count)
 	}
-	wg.Wait()
 
 	logger.Debug("Verifying block range ",
 		"startHeight", startHeight, "endHeight", endHeight)
@@ -233,7 +244,7 @@ func (f *ConfirmedHeaderSelector) NewHead(
 			"block", header.Number.Uint64(), "hash", header.Hash)
 	}
 
-	return headers
+	return headers, nil
 }
 
 func NewConfirmedHeaderSelector(cfg HeaderSelectorConfig) (*ConfirmedHeaderSelector,

go/indexer/services/l1/service.go

@@ -215,7 +215,10 @@ func (s *Service) Update(newHeader *types.Header) error {
 		lowest = *highestConfirmed
 	}
 
-	headers := s.headerSelector.NewHead(s.ctx, lowest.Number, newHeader, s.cfg.RawL1Client)
+	headers, err := s.headerSelector.NewHead(s.ctx, lowest.Number, newHeader, s.cfg.RawL1Client)
+	if err != nil {
+		return err
+	}
 	if len(headers) == 0 {
 		return errNoNewBlocks
 	}

go/indexer/services/l2/confirmed_headers.go

@@ -4,18 +4,20 @@ import (
 	"context"
 	"errors"
 	"math/big"
-	"sync"
 	"time"
 
+	"github.com/ethereum-optimism/optimism/go/indexer/services/util"
+	"github.com/ethereum-optimism/optimism/l2geth/rpc"
+
 	"github.com/ethereum-optimism/optimism/l2geth/core/types"
-	l2ethclient "github.com/ethereum-optimism/optimism/l2geth/ethclient"
 	"github.com/ethereum-optimism/optimism/l2geth/log"
+	l2rpc "github.com/ethereum-optimism/optimism/l2geth/rpc"
 )
 
 const (
 	DefaultConnectionTimeout        = 20 * time.Second
 	DefaultConfDepth         uint64 = 20
-	DefaultMaxBatchSize      uint64 = 100
+	DefaultMaxBatchSize             = 50
 )
 
 type HeaderSelectorConfig struct {
@@ -27,12 +29,42 @@ type ConfirmedHeaderSelector struct {
 	cfg HeaderSelectorConfig
 }
 
+func HeadersByRange(ctx context.Context, client *l2rpc.Client, startHeight uint64, count int) ([]*types.Header, error) {
+	height := startHeight
+	batchElems := make([]rpc.BatchElem, count)
+	for i := 0; i < count; i++ {
+		batchElems[i] = rpc.BatchElem{
+			Method: "eth_getBlockByNumber",
+			Args: []interface{}{
+				util.ToBlockNumArg(new(big.Int).SetUint64(height + uint64(i))),
+				false,
+			},
+			Result: new(types.Header),
+			Error:  nil,
+		}
+	}
+
+	if err := client.BatchCallContext(ctx, batchElems); err != nil {
+		return nil, err
+	}
+
+	out := make([]*types.Header, count)
+	for i := 0; i < len(batchElems); i++ {
+		if batchElems[i].Error != nil {
+			return nil, batchElems[i].Error
+		}
+		out[i] = batchElems[i].Result.(*types.Header)
+	}
+
+	return out, nil
+}
+
 func (f *ConfirmedHeaderSelector) NewHead(
 	ctx context.Context,
 	lowest uint64,
 	header *types.Header,
-	client *l2ethclient.Client,
-) []*types.Header {
+	client *l2rpc.Client,
+) ([]*types.Header, error) {
 
 	number := header.Number.Uint64()
 	blockHash := header.Hash()
@@ -40,14 +72,14 @@ func (f *ConfirmedHeaderSelector) NewHead(
 	logger.Info("New block", "block", number, "hash", blockHash)
 
 	if number < f.cfg.ConfDepth {
-		return nil
+		return nil, nil
 	}
 	endHeight := number - f.cfg.ConfDepth + 1
 
 	minNextHeight := lowest + f.cfg.ConfDepth
 	if minNextHeight > number {
 		log.Info("Fork block=%d hash=%s", number, blockHash)
-		return nil
+		return nil, nil
 	}
 	startHeight := lowest + 1
 
@@ -56,34 +88,35 @@ func (f *ConfirmedHeaderSelector) NewHead(
 		endHeight = startHeight + f.cfg.MaxBatchSize - 1
 	}
 
-	nHeaders := endHeight - startHeight + 1
+	nHeaders := int(endHeight - startHeight + 1)
 	if nHeaders > 1 {
-		logger.Info("Loading block batch ",
+		logger.Info("Loading blocks",
 			"startHeight", startHeight, "endHeight", endHeight)
 	}
 
-	headers := make([]*types.Header, nHeaders)
-	var wg sync.WaitGroup
-	for i := uint64(0); i < nHeaders; i++ {
-		wg.Add(1)
-		go func(ii uint64) {
-			defer wg.Done()
+	headers := make([]*types.Header, 0)
+	height := startHeight
+	left := nHeaders - len(headers)
+	for left > 0 {
+		count := DefaultMaxBatchSize
+		if count > left {
+			count = left
+		}
 
-			ctxt, cancel := context.WithTimeout(ctx, DefaultConnectionTimeout)
-			defer cancel()
+		logger.Info("Loading block batch",
+			"height", height, "count", count)
 
-			height := startHeight + ii
-			bigHeight := new(big.Int).SetUint64(height)
-			header, err := client.HeaderByNumber(ctxt, bigHeight)
+		ctxt, cancel := context.WithTimeout(ctx, DefaultConnectionTimeout)
+		fetched, err := HeadersByRange(ctxt, client, height, count)
+		cancel()
 		if err != nil {
-				log.Error("Unable to load block ", "block", height, "err", err)
-				return
+			return nil, err
 		}
 
-			headers[ii] = header
-		}(i)
+		headers = append(headers, fetched...)
+		left = nHeaders - len(headers)
+		height += uint64(count)
 	}
-	wg.Wait()
 
 	logger.Debug("Verifying block range ",
 		"startHeight", startHeight, "endHeight", endHeight)
@@ -112,7 +145,7 @@ func (f *ConfirmedHeaderSelector) NewHead(
 			"block", header.Number.Uint64(), "hash", header.Hash())
 	}
 
-	return headers
+	return headers, nil
 }
 
 func NewConfirmedHeaderSelector(cfg HeaderSelectorConfig) (*ConfirmedHeaderSelector,

go/indexer/services/l2/service.go

@@ -10,6 +10,8 @@ import (
 	"sync"
 	"time"
 
+	l2rpc "github.com/ethereum-optimism/optimism/l2geth/rpc"
+
 	"github.com/ethereum-optimism/optimism/go/indexer/metrics"
 	"github.com/ethereum-optimism/optimism/go/indexer/server"
 	"github.com/prometheus/client_golang/prometheus"
@@ -58,6 +60,7 @@ func HeaderByNumberWithRetry(ctx context.Context,
 type ServiceConfig struct {
 	Context            context.Context
 	Metrics            *metrics.Metrics
+	L2RPC              *l2rpc.Client
 	L2Client           *l2ethclient.Client
 	ChainID            *big.Int
 	ConfDepth          uint64
@@ -190,7 +193,10 @@ func (s *Service) Update(newHeader *types.Header) error {
 		lowest = *highestConfirmed
 	}
 
-	headers := s.headerSelector.NewHead(s.ctx, lowest.Number, newHeader, s.cfg.L2Client)
+	headers, err := s.headerSelector.NewHead(s.ctx, lowest.Number, newHeader, s.cfg.L2RPC)
+	if err != nil {
+		return err
+	}
 	if len(headers) == 0 {
 		return errNoNewBlocks
 	}

go/indexer/services/util/util.go

+package util
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
+)
+
+func ToBlockNumArg(number *big.Int) string {
+	if number == nil {
+		return "latest"
+	}
+	pending := big.NewInt(-1)
+	if number.Cmp(pending) == 0 {
+		return "pending"
+	}
+	return hexutil.EncodeBig(number)
+}