add finality depth contraint in block subscriber

core/services/ocr2/plugins/ocr2keeper/evm21/block_subscriber.go

@@ -50,12 +50,13 @@ type BlockSubscriber struct {
 	latestBlock      atomic.Pointer[ocr2keepers.BlockKey]
 	blockHistorySize int64
 	blockSize        int64
+	finalityDepth    uint32
 	lggr             logger.Logger
 }
 
 var _ ocr2keepers.BlockSubscriber = &BlockSubscriber{}
 
-func NewBlockSubscriber(hb httypes.HeadBroadcaster, lp logpoller.LogPoller, lggr logger.Logger) *BlockSubscriber {
+func NewBlockSubscriber(hb httypes.HeadBroadcaster, lp logpoller.LogPoller, finalityDepth uint32, lggr logger.Logger) *BlockSubscriber {
 	return &BlockSubscriber{
 		threadCtrl:       utils.NewThreadControl(),
 		hb:               hb,
@@ -65,6 +66,7 @@ func NewBlockSubscriber(hb httypes.HeadBroadcaster, lp logpoller.LogPoller, lggr
 		blocks:           map[int64]string{},
 		blockHistorySize: blockHistorySize,
 		blockSize:        lookbackDepth,
+		finalityDepth:    finalityDepth,
 		latestBlock:      atomic.Pointer[ocr2keepers.BlockKey]{},
 		lggr:             lggr.Named("BlockSubscriber"),
 	}
@@ -226,10 +228,13 @@ func (bs *BlockSubscriber) processHead(h *evmtypes.Head) {
 	// head parent is a linked list with EVM finality depth
 	// when re-org happens, new heads will have pointers to the new blocks
 	i := int64(0)
-	for cp := h; ; cp = cp.Parent {
-		if cp == nil || bs.blocks[cp.Number] == cp.Hash.Hex() {
-			break
-		}
+	for cp := h; cp != nil; cp = cp.Parent {
+		// we don't stop when a matching (block number/hash) entry is seen in the map because parent linked list may be
+		// cut short during a re-org if head broadcaster backfill is not complete. This can cause some re-orged blocks
+		// left in the map. for example, re-org happens for block 98, 99, 100. next head 101 from broadcaster has parent list
+		// of 100, so block 100 and 101 are updated. when next head 102 arrives, it has full parent history of finality depth.
+		// if we stop when we see a block number/hash match, we won't look back and correct block 98 and 99.
+		// hence, we make a compromise here and check previous max(finality depth, blockSize) blocks and update the map.
 		existingHash, ok := bs.blocks[cp.Number]
 		if !ok {
 			bs.lggr.Debugf("filling block %d with new hash %s", cp.Number, cp.Hash.Hex())
@@ -238,7 +243,7 @@ func (bs *BlockSubscriber) processHead(h *evmtypes.Head) {
 		}
 		bs.blocks[cp.Number] = cp.Hash.Hex()
 		i++
-		if i > bs.blockSize {
+		if i > int64(bs.finalityDepth) || i > bs.blockSize {
 			break
 		}
 	}

core/services/ocr2/plugins/ocr2keeper/evm21/block_subscriber_test.go

@@ -22,13 +22,14 @@ import (
 
 const historySize = 4
 const blockSize = int64(4)
+const finality = uint32(4)
 
 func TestBlockSubscriber_Subscribe(t *testing.T) {
 	lggr := logger.TestLogger(t)
 	var hb types.HeadBroadcaster
 	var lp logpoller.LogPoller
 
-	bs := NewBlockSubscriber(hb, lp, lggr)
+	bs := NewBlockSubscriber(hb, lp, finality, lggr)
 	bs.blockHistorySize = historySize
 	bs.blockSize = blockSize
 	subId, _, err := bs.Subscribe()
@@ -47,7 +48,7 @@ func TestBlockSubscriber_Unsubscribe(t *testing.T) {
 	var hb types.HeadBroadcaster
 	var lp logpoller.LogPoller
 
-	bs := NewBlockSubscriber(hb, lp, lggr)
+	bs := NewBlockSubscriber(hb, lp, finality, lggr)
 	bs.blockHistorySize = historySize
 	bs.blockSize = blockSize
 	subId, _, err := bs.Subscribe()
@@ -65,7 +66,7 @@ func TestBlockSubscriber_Unsubscribe_Failure(t *testing.T) {
 	var hb types.HeadBroadcaster
 	var lp logpoller.LogPoller
 
-	bs := NewBlockSubscriber(hb, lp, lggr)
+	bs := NewBlockSubscriber(hb, lp, finality, lggr)
 	bs.blockHistorySize = historySize
 	bs.blockSize = blockSize
 	err := bs.Unsubscribe(2)
@@ -97,7 +98,7 @@ func TestBlockSubscriber_GetBlockRange(t *testing.T) {
 		t.Run(tc.Name, func(t *testing.T) {
 			lp := new(mocks.LogPoller)
 			lp.On("LatestBlock", mock.Anything).Return(tc.LatestBlock, tc.LatestBlockErr)
-			bs := NewBlockSubscriber(hb, lp, lggr)
+			bs := NewBlockSubscriber(hb, lp, finality, lggr)
 			bs.blockHistorySize = historySize
 			bs.blockSize = blockSize
 			blocks, err := bs.getBlockRange(testutils.Context(t))
@@ -155,7 +156,7 @@ func TestBlockSubscriber_InitializeBlocks(t *testing.T) {
 		t.Run(tc.Name, func(t *testing.T) {
 			lp := new(mocks.LogPoller)
 			lp.On("GetBlocksRange", mock.Anything, tc.Blocks, mock.Anything).Return(tc.PollerBlocks, tc.Error)
-			bs := NewBlockSubscriber(hb, lp, lggr)
+			bs := NewBlockSubscriber(hb, lp, finality, lggr)
 			bs.blockHistorySize = historySize
 			bs.blockSize = blockSize
 			err := bs.initializeBlocks(testutils.Context(t), tc.Blocks)
@@ -213,7 +214,7 @@ func TestBlockSubscriber_BuildHistory(t *testing.T) {
 
 	for _, tc := range tests {
 		t.Run(tc.Name, func(t *testing.T) {
-			bs := NewBlockSubscriber(hb, lp, lggr)
+			bs := NewBlockSubscriber(hb, lp, finality, lggr)
 			bs.blockHistorySize = historySize
 			bs.blockSize = blockSize
 			bs.blocks = tc.Blocks
@@ -258,7 +259,7 @@ func TestBlockSubscriber_Cleanup(t *testing.T) {
 
 	for _, tc := range tests {
 		t.Run(tc.Name, func(t *testing.T) {
-			bs := NewBlockSubscriber(hb, lp, lggr)
+			bs := NewBlockSubscriber(hb, lp, finality, lggr)
 			bs.blockHistorySize = historySize
 			bs.blockSize = blockSize
 			bs.blocks = tc.Blocks
@@ -300,7 +301,7 @@ func TestBlockSubscriber_Start(t *testing.T) {
 
 	lp.On("GetBlocksRange", mock.Anything, blocks, mock.Anything).Return(pollerBlocks, nil)
 
-	bs := NewBlockSubscriber(hb, lp, lggr)
+	bs := NewBlockSubscriber(hb, lp, finality, lggr)
 	bs.blockHistorySize = historySize
 	bs.blockSize = blockSize
 	err := bs.Start(context.Background())

core/services/ocr2/plugins/ocr2keeper/evm21/registry_check_pipeline.go

@@ -99,20 +99,21 @@ func (r *EvmRegistry) getBlockHash(blockNumber *big.Int) (common.Hash, error) {
 
 // verifyCheckBlock checks that the check block and hash are valid, returns the pipeline execution state and retryable
 func (r *EvmRegistry) verifyCheckBlock(_ context.Context, checkBlock, upkeepId *big.Int, checkHash common.Hash) (state encoding.PipelineExecutionState, retryable bool) {
-	var h string
-	var ok bool
 	// verify check block number and hash are valid
-	h, ok = r.bs.queryBlocksMap(checkBlock.Int64())
-	if !ok {
-		r.lggr.Warnf("check block %s does not exist in block subscriber for upkeepId %s, querying eth client", checkBlock, upkeepId)
-		b, err := r.getBlockHash(checkBlock)
-		if err != nil {
-			r.lggr.Warnf("failed to query block %s: %s", checkBlock, err.Error())
-			return encoding.RpcFlakyFailure, true
-		}
-		h = b.Hex()
+	h, ok := r.bs.queryBlocksMap(checkBlock.Int64())
+	// if this block number/hash combo exists in block subscriber, this check block and hash still exist on chain and are valid
+	// the block hash in block subscriber might be slightly outdated, if it doesn't match then we fetch the latest from RPC.
+	if ok && h == checkHash.Hex() {
+		r.lggr.Debugf("check block hash %s exists on chain at block number %d for upkeepId %s", checkHash.Hex(), checkBlock, upkeepId)
+		return encoding.NoPipelineError, false
+	}
+	r.lggr.Warnf("check block %s does not exist in block subscriber or hash does not match for upkeepId %s. this may be caused by block subscriber outdated due to re-org, querying eth client to confirm", checkBlock, upkeepId)
+	b, err := r.getBlockHash(checkBlock)
+	if err != nil {
+		r.lggr.Warnf("failed to query block %s: %s", checkBlock, err.Error())
+		return encoding.RpcFlakyFailure, true
 	}
-	if checkHash.Hex() != h {
+	if checkHash.Hex() != b.Hex() {
 		r.lggr.Warnf("check block %s hash do not match. %s from block subscriber vs %s from trigger for upkeepId %s", checkBlock, h, checkHash.Hex(), upkeepId)
 		return encoding.CheckBlockInvalid, false
 	}
@@ -126,11 +127,15 @@ func (r *EvmRegistry) verifyLogExists(upkeepId *big.Int, p ocr2keepers.UpkeepPay
 	// if log block number is populated, check log block number and block hash
 	if logBlockNumber != 0 {
 		h, ok := r.bs.queryBlocksMap(logBlockNumber)
+		// if this block number/hash combo exists in block subscriber, this block and tx still exists on chain and is valid
+		// the block hash in block subscriber might be slightly outdated, if it doesn't match then we fetch the latest from RPC.
 		if ok && h == logBlockHash.Hex() {
 			r.lggr.Debugf("tx hash %s exists on chain at block number %d, block hash %s for upkeepId %s", hexutil.Encode(p.Trigger.LogTriggerExtension.TxHash[:]), logBlockHash.Hex(), logBlockNumber, upkeepId)
 			return encoding.UpkeepFailureReasonNone, encoding.NoPipelineError, false
 		}
-		r.lggr.Debugf("log block %d does not exist in block subscriber for upkeepId %s, querying eth client", logBlockNumber, upkeepId)
+		// if this block does not exist in the block subscriber, the block which this log lived on was probably re-orged
+		// hence, check eth client for this log's tx hash to confirm
+		r.lggr.Debugf("log block %d does not exist in block subscriber or block hash does not match for upkeepId %s. this may be caused by block subscriber outdated due to re-org, querying eth client to confirm", logBlockNumber, upkeepId)
 	} else {
 		r.lggr.Debugf("log block not provided, querying eth client for tx hash %s for upkeepId %s", hexutil.Encode(p.Trigger.LogTriggerExtension.TxHash[:]), upkeepId)
 	}

core/services/ocr2/plugins/ocr2keeper/evm21/registry_check_pipeline_test.go

@@ -144,6 +144,15 @@ func TestRegistry_VerifyCheckBlock(t *testing.T) {
 				Trigger:  ocr2keepers.NewTrigger(500, common.HexToHash("0x5bff03de234fe771ac0d685f9ee0fb0b757ea02ec9e6f10e8e2ee806db1b6b83")),
 				WorkID:   "work",
 			},
+			poller: &mockLogPoller{
+				GetBlocksRangeFn: func(ctx context.Context, numbers []uint64, qopts ...pg.QOpt) ([]logpoller.LogPollerBlock, error) {
+					return []logpoller.LogPollerBlock{
+						{
+							BlockHash: common.HexToHash("0xcba5cf9e2bb32373c76015384e1098912d9510a72481c78057fcb088209167de"),
+						},
+					}, nil
+				},
+			},
 			blocks: map[int64]string{
 				500: "0xa518faeadcc423338c62572da84dda35fe44b34f521ce88f6081b703b250cca4",
 			},

core/services/ocr2/plugins/ocr2keeper/evm21/registry_test.go

@@ -501,7 +501,7 @@ func TestRegistry_refreshLogTriggerUpkeeps(t *testing.T) {
 			var hb types3.HeadBroadcaster
 			var lp logpoller.LogPoller
 
-			bs := NewBlockSubscriber(hb, lp, lggr)
+			bs := NewBlockSubscriber(hb, lp, 1000, lggr)
 
 			registry := &EvmRegistry{
 				addr:             common.BigToAddress(big.NewInt(1)),

core/services/ocr2/plugins/ocr2keeper/evm21/services.go

@@ -78,7 +78,7 @@ func New(addr common.Address, client evm.Chain, mc *models.MercuryCredentials, k
 	logProvider, logRecoverer := logprovider.New(lggr, client.LogPoller(), client.Client(), utilsABI, services.upkeepState, finalityDepth)
 	services.logProvider = logProvider
 	services.logRecoverer = logRecoverer
-	services.blockSub = NewBlockSubscriber(client.HeadBroadcaster(), client.LogPoller(), lggr)
+	services.blockSub = NewBlockSubscriber(client.HeadBroadcaster(), client.LogPoller(), finalityDepth, lggr)
 
 	services.keyring = NewOnchainKeyringV3Wrapper(keyring)