From 4f06a3f0935598ca156c288f37a562b7a66961bf Mon Sep 17 00:00:00 2001
From: "F. Eugene Aumson" <feuGeneA@users.noreply.github.com>
Date: Wed, 15 Nov 2023 03:03:34 +0000
Subject: [PATCH] paginate eth_getLogs calls

---
 vms/evm/subscriber.go      | 35 ++++++++++++++++++++---------------
 vms/evm/subscriber_test.go |  9 ++++++++-
 2 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/vms/evm/subscriber.go b/vms/evm/subscriber.go
index 9a6266ce..854ca947 100644
--- a/vms/evm/subscriber.go
+++ b/vms/evm/subscriber.go
@@ -129,8 +129,8 @@ func (s *subscriber) forwardLogs() {
 }
 
 // Process logs from the given block height to the latest block
-// Cap the number of blocks requested from the client to MaxBlocksToProcess,
-// counting back from the current block.
+// Paginates ethClient.FilterLogs requests into block ranges spanning
+// MaxBlocksToProcess, counting back from the current block.
 func (s *subscriber) ProcessFromHeight(height *big.Int) error {
 	s.logger.Info(
 		"Processing historical logs",
@@ -156,18 +156,6 @@ func (s *subscriber) ProcessFromHeight(height *big.Int) error {
 		return err
 	}
 
-	// Cap the number of blocks to process to MaxBlocksToProcess
-	toBlock := big.NewInt(0).SetUint64(latestBlock)
-	if height.Cmp(big.NewInt(0).Sub(toBlock, big.NewInt(MaxBlocksToProcess))) < 0 {
-		s.logger.Warn(
-			fmt.Sprintf("Requested to process too many blocks. Processing only the most recent %d blocks", MaxBlocksToProcess),
-			zap.String("requestedBlockHeight", height.String()),
-			zap.String("latestBlockHeight", toBlock.String()),
-			zap.String("chainID", s.chainID.String()),
-		)
-		height = big.NewInt(0).Add(toBlock, big.NewInt(-MaxBlocksToProcess))
-	}
-
 	// Filter logs from the latest processed block to the latest block
 	// Since initializationFilterQuery does not modify existing fields of warpFilterQuery,
 	// we can safely reuse warpFilterQuery with only a shallow copy
@@ -218,7 +206,24 @@ func (s *subscriber) ProcessFromHeight(height *big.Int) error {
 		return nil
 	}
 
-	return processBlockRange(height, toBlock)
+	bigLatestBlock := big.NewInt(0).SetUint64(latestBlock)
+
+	for fromBlock := height; fromBlock.Cmp(bigLatestBlock) <= 0; /*see post statement in body*/ {
+		toBlock := big.NewInt(0).Add(fromBlock, big.NewInt(MaxBlocksToProcess))
+		if toBlock.Cmp(bigLatestBlock) > 0 {
+			toBlock = bigLatestBlock
+		}
+
+		err = processBlockRange(fromBlock, toBlock)
+		if err != nil {
+			return err
+		}
+
+		// loop post statement:
+		fromBlock.Add(toBlock, big.NewInt(1))
+	}
+
+	return nil
 }
 
 func (s *subscriber) SetProcessedBlockHeightToLatest() error {
diff --git a/vms/evm/subscriber_test.go b/vms/evm/subscriber_test.go
index 4236c284..009d9276 100644
--- a/vms/evm/subscriber_test.go
+++ b/vms/evm/subscriber_test.go
@@ -111,7 +111,14 @@ func TestCatchingUpOn300Blocks(t *testing.T) {
 	mockEthClient.EXPECT().FilterLogs(
 		gomock.Any(),
 		makeWarpBlockFilterQuery(
-			big.NewInt(800),
+			big.NewInt(700),
+			big.NewInt(900),
+		),
+	).Return([]types.Log{}, nil).Times(1)
+	mockEthClient.EXPECT().FilterLogs(
+		gomock.Any(),
+		makeWarpBlockFilterQuery(
+			big.NewInt(901),
 			big.NewInt(0).SetUint64(latestBlock),
 		),
 	).Return([]types.Log{}, nil).Times(1)