fix: syncer spamming RPC and reaching tip of chain (cherry-pick from CDK)

README.md

@@ -74,3 +74,4 @@ Licensed under either of
 at your option. 
 
 The SPDX license identifier for this project is `MIT OR Apache-2.0`.
+

sync/evmdownloader.go

@@ -39,8 +39,9 @@ type LogAppenderMap map[common.Hash]func(b *EVMBlock, l types.Log) error
 type EVMDownloader struct {
 	syncBlockChunkSize uint64
 	EVMDownloaderInterface
-	log                *log.Logger
-	finalizedBlockType etherman.BlockNumberFinality
+	log                        *log.Logger
+	finalizedBlockType         etherman.BlockNumberFinality
+	stopDownloaderOnIterationN int
 }
 
 func NewEVMDownloader(
@@ -101,9 +102,16 @@ func NewEVMDownloader(
 	}, nil
 }
 
+// setStopDownloaderOnIterationN sets the block number to stop the downloader (just for unittest)
+func (d *EVMDownloader) setStopDownloaderOnIterationN(iteration int) {
+	d.stopDownloaderOnIterationN = iteration
+}
+
 func (d *EVMDownloader) Download(ctx context.Context, fromBlock uint64, downloadedCh chan EVMBlock) {
 	lastBlock := d.WaitForNewBlocks(ctx, 0)
-
+	toBlock := fromBlock + d.syncBlockChunkSize
+	iteration := 0
+	reachTop := false
 	for {
 		select {
 		case <-ctx.Done():
@@ -112,53 +120,68 @@ func (d *EVMDownloader) Download(ctx context.Context, fromBlock uint64, download
 			return
 		default:
 		}
+		d.log.Debugf("range: %d to %d, last block: %d", fromBlock, toBlock, lastBlock)
 
-		toBlock := fromBlock + d.syncBlockChunkSize
-		if toBlock > lastBlock {
-			toBlock = lastBlock
-		}
-
-		if fromBlock > toBlock {
+		if fromBlock > lastBlock || (reachTop && toBlock >= lastBlock) {
 			d.log.Debugf(
-				"waiting for new blocks, last block processed: %d, last block seen on L1: %d",
-				fromBlock-1, lastBlock,
+				"waiting for new blocks, current range: [%d to %d], last block seen: %d",
+				fromBlock, toBlock, lastBlock,
 			)
-			lastBlock = d.WaitForNewBlocks(ctx, fromBlock-1)
-			continue
-		}
+			lastBlock = d.WaitForNewBlocks(ctx, lastBlock)
+			d.log.Debugf("new last block seen: %d", lastBlock)
 
+			if fromBlock-toBlock < d.syncBlockChunkSize {
+				toBlock = fromBlock + d.syncBlockChunkSize
+			}
+		}
+		reachTop = false
 		lastFinalizedBlock, err := d.GetLastFinalizedBlock(ctx)
 		if err != nil {
 			d.log.Error("error getting last finalized block: ", err)
 			continue
 		}
+		// lastFinalizedBlock can't be > lastBlock
+		lastFinalizedBlockNumber := min(lastBlock, lastFinalizedBlock.Number.Uint64())
 
-		lastFinalizedBlockNumber := lastFinalizedBlock.Number.Uint64()
-
-		d.log.Debugf("getting events from blocks %d to  %d. lastFinalizedBlock: %d",
-			fromBlock, toBlock, lastFinalizedBlockNumber)
-		blocks := d.GetEventsByBlockRange(ctx, fromBlock, toBlock)
-
+		requestToBlock := toBlock
+		if toBlock >= lastBlock {
+			requestToBlock = lastBlock
+			reachTop = true
+		}
+		d.log.Debugf("getting events from blocks [%d to  %d] toBlock: %d. lastFinalizedBlock: %d lastBlock: %d",
+			fromBlock, requestToBlock, toBlock, lastFinalizedBlockNumber, lastBlock)
+		blocks := d.GetEventsByBlockRange(ctx, fromBlock, requestToBlock)
+		d.log.Debugf("result events from blocks [%d to  %d] -> len(blocks)=%d",
+			fromBlock, requestToBlock, len(blocks))
 		if toBlock <= lastFinalizedBlockNumber {
 			d.reportBlocks(downloadedCh, blocks, lastFinalizedBlockNumber)
-			fromBlock = toBlock + 1
-
 			if blocks.Len() == 0 || blocks[blocks.Len()-1].Num < toBlock {
 				d.reportEmptyBlock(ctx, downloadedCh, toBlock, lastFinalizedBlockNumber)
 			}
+			fromBlock = toBlock + 1
+			toBlock = fromBlock + d.syncBlockChunkSize
 		} else {
-			d.reportBlocks(downloadedCh, blocks, lastFinalizedBlockNumber)
-
 			if blocks.Len() == 0 {
-				if lastFinalizedBlockNumber > fromBlock &&
-					lastFinalizedBlockNumber-fromBlock > d.syncBlockChunkSize {
-					d.reportEmptyBlock(ctx, downloadedCh, fromBlock+d.syncBlockChunkSize, lastFinalizedBlockNumber)
-					fromBlock += d.syncBlockChunkSize + 1
+				if lastFinalizedBlockNumber >= fromBlock {
+					emptyBlock := lastFinalizedBlockNumber
+					d.reportEmptyBlock(ctx, downloadedCh, emptyBlock, lastFinalizedBlockNumber)
+					fromBlock = emptyBlock + 1
+					toBlock = fromBlock + d.syncBlockChunkSize
+				} else {
+					// Extend range until find logs or reach the last finalized block
+					toBlock += d.syncBlockChunkSize
 				}
 			} else {
+				d.reportBlocks(downloadedCh, blocks, lastFinalizedBlockNumber)
 				fromBlock = blocks[blocks.Len()-1].Num + 1
+				toBlock = fromBlock + d.syncBlockChunkSize
 			}
 		}
+		iteration++
+		if d.stopDownloaderOnIterationN != 0 && iteration >= d.stopDownloaderOnIterationN {
+			d.log.Infof("stop downloader on iteration %d", iteration)
+			return
+		}
 	}
 }