Add logs to identify when assumptions of log queuing behaviour are violated

.changeset/heavy-mails-rule.md

@@ -0,0 +1,5 @@
+---
+"chainlink": patch
+---
+
+Add logs for when the assumptions of how the log buffer will be used are violated #internal

core/services/ocr2/plugins/ocr2keeper/evmregistry/v21/logprovider/buffer_v1.go

@@ -76,38 +76,80 @@ type logBuffer struct {
 	lastBlockSeen *atomic.Int64
 	// map of upkeep id to its queue
 	queues map[string]*upkeepLogQueue
-	lock   sync.RWMutex
+	// map for then number of times we have enqueued logs for a block number
+	enqueuedBlocks map[int64]map[string]int
+	lock           sync.RWMutex
 }
 
 func NewLogBuffer(lggr logger.Logger, lookback, blockRate, logLimit uint32) LogBuffer {
 	return &logBuffer{
-		lggr:          lggr.Named("KeepersRegistry.LogEventBufferV1"),
-		opts:          newLogBufferOptions(lookback, blockRate, logLimit),
-		lastBlockSeen: new(atomic.Int64),
-		queues:        make(map[string]*upkeepLogQueue),
+		lggr:           lggr.Named("KeepersRegistry.LogEventBufferV1"),
+		opts:           newLogBufferOptions(lookback, blockRate, logLimit),
+		lastBlockSeen:  new(atomic.Int64),
+		enqueuedBlocks: map[int64]map[string]int{},
+		queues:         make(map[string]*upkeepLogQueue),
 	}
 }
 
 // Enqueue adds logs to the buffer and might also drop logs if the limit for the
 // given upkeep was exceeded. It will create a new buffer if it does not exist.
+// Logs are expected to be enqueued in increasing order of block number.
+// All logs for an upkeep on a particular block will be enqueued in a single Enqueue call.
 // Returns the number of logs that were added and number of logs that were  dropped.
 func (b *logBuffer) Enqueue(uid *big.Int, logs ...logpoller.Log) (int, int) {
 	buf, ok := b.getUpkeepQueue(uid)
 	if !ok || buf == nil {
 		buf = newUpkeepLogQueue(b.lggr, uid, b.opts)
 		b.setUpkeepQueue(uid, buf)
 	}
-	latestBlock := latestBlockNumber(logs...)
-	if b.lastBlockSeen.Load() < latestBlock {
-		b.lastBlockSeen.Store(latestBlock)
+
+	latestLogBlock, uniqueBlocks := blockStatistics(logs...)
+	if lastBlockSeen := b.lastBlockSeen.Load(); lastBlockSeen < latestLogBlock {
+		b.lastBlockSeen.Store(latestLogBlock)
+	} else if latestLogBlock < lastBlockSeen {
+		b.lggr.Debugw("enqueuing logs from a block older than latest seen block", "logBlock", latestLogBlock, "lastBlockSeen", lastBlockSeen)
 	}
+
+	b.trackBlockNumbersForUpkeep(uid, uniqueBlocks)
+
 	blockThreshold := b.lastBlockSeen.Load() - int64(b.opts.lookback.Load())
 	if blockThreshold <= 0 {
 		blockThreshold = 1
 	}
+
+	// clean up enqueued block counts
+	for block := range b.enqueuedBlocks {
+		if block < blockThreshold {
+			delete(b.enqueuedBlocks, block)
+		}
+	}
+
 	return buf.enqueue(blockThreshold, logs...)
 }
 
+// trackBlockNumbersForUpkeep keeps track of the number of times we enqueue logs for an upkeep,
+// for a specific block number. The expectation is that we will only enqueue logs for an upkeep for a
+// specific block number once, i.e. all logs for an upkeep for a block, will be enqueued in a single
+// enqueue call. In the event that we see upkeep logs enqueued for a particular block more than once,
+// we log a message.
+func (b *logBuffer) trackBlockNumbersForUpkeep(uid *big.Int, uniqueBlocks map[int64]bool) {
+	for blockNumber := range uniqueBlocks {
+		if blockNumbers, ok := b.enqueuedBlocks[blockNumber]; ok {
+			if upkeepBlockInstances, ok := blockNumbers[uid.String()]; ok {
+				blockNumbers[uid.String()] = upkeepBlockInstances + 1
+				b.lggr.Debugw("enqueuing logs again for a previously seen block for this upkeep", "blockNumber", blockNumber, "numberOfEnqueues", b.enqueuedBlocks[blockNumber], "upkeepID", uid.String())
+			} else {
+				blockNumbers[uid.String()] = 1
+			}
+			b.enqueuedBlocks[blockNumber] = blockNumbers
+		} else {
+			b.enqueuedBlocks[blockNumber] = map[string]int{
+				uid.String(): 1,
+			}
+		}
+	}
+}
+
 // Dequeue greedly pulls logs from the buffers.
 // Returns logs and the number of remaining logs in the buffer.
 func (b *logBuffer) Dequeue(block int64, blockRate, upkeepLimit, maxResults int, upkeepSelector func(id *big.Int) bool) ([]BufferedLog, int) {

core/services/ocr2/plugins/ocr2keeper/evmregistry/v21/logprovider/buffer_v1_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"github.com/smartcontractkit/chainlink/v2/core/chains/evm/logpoller"
@@ -50,6 +51,96 @@ func TestLogEventBufferV1_SyncFilters(t *testing.T) {
 	require.Equal(t, 1, buf.NumOfUpkeeps())
 }
 
+type readableLogger struct {
+	logger.Logger
+	DebugwFn func(msg string, keysAndValues ...interface{})
+	NamedFn  func(name string) logger.Logger
+	WithFn   func(args ...interface{}) logger.Logger
+}
+
+func (l *readableLogger) Debugw(msg string, keysAndValues ...interface{}) {
+	l.DebugwFn(msg, keysAndValues...)
+}
+
+func (l *readableLogger) Named(name string) logger.Logger {
+	return l
+}
+
+func (l *readableLogger) With(args ...interface{}) logger.Logger {
+	return l
+}
+
+func TestLogEventBufferV1_Enqueueviolations(t *testing.T) {
+	t.Run("enqueuing logs for a block older than latest seen logs a message", func(t *testing.T) {
+		logReceived := false
+		readableLogger := &readableLogger{
+			DebugwFn: func(msg string, keysAndValues ...interface{}) {
+				if msg == "enqueuing logs from a block older than latest seen block" {
+					logReceived = true
+					assert.Equal(t, "logBlock", keysAndValues[0])
+					assert.Equal(t, int64(1), keysAndValues[1])
+					assert.Equal(t, "lastBlockSeen", keysAndValues[2])
+					assert.Equal(t, int64(2), keysAndValues[3])
+				}
+			},
+		}
+
+		logBufferV1 := NewLogBuffer(readableLogger, 10, 20, 1)
+
+		buf := logBufferV1.(*logBuffer)
+
+		buf.Enqueue(big.NewInt(1),
+			logpoller.Log{BlockNumber: 2, TxHash: common.HexToHash("0x1"), LogIndex: 0},
+			logpoller.Log{BlockNumber: 2, TxHash: common.HexToHash("0x1"), LogIndex: 1},
+		)
+		buf.Enqueue(big.NewInt(2),
+			logpoller.Log{BlockNumber: 1, TxHash: common.HexToHash("0x2"), LogIndex: 0},
+		)
+
+		assert.Equal(t, 1, buf.enqueuedBlocks[2]["1"])
+		assert.Equal(t, 1, buf.enqueuedBlocks[1]["2"])
+		assert.True(t, true, logReceived)
+	})
+
+	t.Run("enqueuing logs for the same block over multiple calls logs a message", func(t *testing.T) {
+		logReceived := false
+		readableLogger := &readableLogger{
+			DebugwFn: func(msg string, keysAndValues ...interface{}) {
+				if msg == "enqueuing logs again for a previously seen block" {
+					logReceived = true
+					assert.Equal(t, "blockNumber", keysAndValues[0])
+					assert.Equal(t, int64(3), keysAndValues[1])
+					assert.Equal(t, "numberOfEnqueues", keysAndValues[2])
+					assert.Equal(t, 2, keysAndValues[3])
+				}
+			},
+		}
+
+		logBufferV1 := NewLogBuffer(readableLogger, 10, 20, 1)
+
+		buf := logBufferV1.(*logBuffer)
+
+		buf.Enqueue(big.NewInt(1),
+			logpoller.Log{BlockNumber: 1, TxHash: common.HexToHash("0x1"), LogIndex: 0},
+			logpoller.Log{BlockNumber: 1, TxHash: common.HexToHash("0x1"), LogIndex: 1},
+		)
+		buf.Enqueue(big.NewInt(2),
+			logpoller.Log{BlockNumber: 2, TxHash: common.HexToHash("0x2"), LogIndex: 0},
+		)
+		buf.Enqueue(big.NewInt(3),
+			logpoller.Log{BlockNumber: 3, TxHash: common.HexToHash("0x3a"), LogIndex: 0},
+		)
+		buf.Enqueue(big.NewInt(3),
+			logpoller.Log{BlockNumber: 3, TxHash: common.HexToHash("0x3b"), LogIndex: 0},
+		)
+
+		assert.Equal(t, 1, buf.enqueuedBlocks[2]["2"])
+		assert.Equal(t, 1, buf.enqueuedBlocks[1]["1"])
+		assert.Equal(t, 2, buf.enqueuedBlocks[3]["3"])
+		assert.True(t, true, logReceived)
+	})
+}
+
 func TestLogEventBufferV1_Dequeue(t *testing.T) {
 	tests := []struct {
 		name         string

core/services/ocr2/plugins/ocr2keeper/evmregistry/v21/logprovider/log.go

@@ -8,7 +8,7 @@ import (
 	"github.com/smartcontractkit/chainlink/v2/core/chains/evm/logpoller"
 )
 
-// LogSorter sorts the logs based on block number, tx hash and log index.
+// LogSorter sorts the logs primarily by block number, then by log index, and finally by tx hash.
 // returns true if b should come before a.
 func LogSorter(a, b logpoller.Log) bool {
 	return LogComparator(a, b) > 0
@@ -57,13 +57,17 @@ func logID(l logpoller.Log) string {
 	return hex.EncodeToString(ext.LogIdentifier())
 }
 
-// latestBlockNumber returns the latest block number from the given logs
-func latestBlockNumber(logs ...logpoller.Log) int64 {
+// blockStatistics returns the latest block number from the given logs, and a map of unique block numbers
+func blockStatistics(logs ...logpoller.Log) (int64, map[int64]bool) {
 	var latest int64
+	uniqueBlocks := map[int64]bool{}
+
 	for _, l := range logs {
 		if l.BlockNumber > latest {
 			latest = l.BlockNumber
 		}
+		uniqueBlocks[l.BlockNumber] = true
 	}
-	return latest
+
+	return latest, uniqueBlocks
 }