combine booststrap and blockevent handle

monitor/btcscanner/block_handler.go

@@ -7,9 +7,28 @@ import (
 	"github.com/lightningnetwork/lnd/chainntnfs"
 )
 
-// blockEventHandler handles connected and disconnected blocks from the BTC client.
-func (bs *BtcScanner) blockEventHandler(blockNotifier *chainntnfs.BlockEpochEvent) {
+// bootstrapAndBlockEventHandler handles connected and disconnected blocks from the BTC client.
+func (bs *BtcScanner) bootstrapAndBlockEventHandler() {
 	defer bs.wg.Done()
+
+	bs.Bootstrap()
+
+	var blockEpoch *chainntnfs.BlockEpoch
+	bestKnownBlock := bs.UnconfirmedBlockCache.Tip()
+	if bestKnownBlock != nil {
+		hash := bestKnownBlock.BlockHash()
+		blockEpoch = &chainntnfs.BlockEpoch{
+			Hash:        &hash,
+			Height:      bestKnownBlock.Height,
+			BlockHeader: bestKnownBlock.Header,
+		}
+	}
+	// register the notifier with the best known tip
+	blockNotifier, err := bs.btcNotifier.RegisterBlockEpochNtfn(blockEpoch)
+	if err != nil {
+		bs.logger.Errorf("Failed registering block epoch notifier")
+		return
+	}
 	defer blockNotifier.Cancel()
 
 	for {
@@ -26,9 +45,7 @@ func (bs *BtcScanner) blockEventHandler(blockNotifier *chainntnfs.BlockEpochEven
 			if err := bs.handleNewBlock(epoch.Height, epoch.BlockHeader); err != nil {
 				bs.logger.Warnf("failed to handle block at height %d: %s, "+
 					"need to restart the bootstrapping process", epoch.Height, err.Error())
-				if bs.Synced.Swap(false) {
-					bs.Bootstrap()
-				}
+				bs.Bootstrap()
 			}
 		}
 	}
@@ -37,10 +54,6 @@ func (bs *BtcScanner) blockEventHandler(blockNotifier *chainntnfs.BlockEpochEven
 // handleNewBlock handles blocks from the BTC client
 // if new confirmed blocks are found, send them through the channel
 func (bs *BtcScanner) handleNewBlock(height int32, header *wire.BlockHeader) error {
-	if !bs.Synced.Load() {
-		return errors.New("the btc scanner is not synced")
-	}
-
 	// get cache tip
 	cacheTip := bs.UnconfirmedBlockCache.Tip()
 	if cacheTip == nil {
@@ -71,7 +84,7 @@ func (bs *BtcScanner) handleNewBlock(height int32, header *wire.BlockHeader) err
 	ib, _, err := bs.BtcClient.GetBlockByHash(&blockHash)
 	if err != nil {
 		// failing to request the block, which means a bug
-		panic(err)
+		panic(fmt.Errorf("failed to request block by hash: %s", blockHash.String()))
 	}
 
 	// otherwise, add the block to the cache

monitor/btcscanner/btc_scanner.go

@@ -40,8 +40,6 @@ type BtcScanner struct {
 	blockHeaderChan chan *wire.BlockHeader
 	checkpointsChan chan *types.CheckpointRecord
 
-	Synced *atomic.Bool
-
 	wg      sync.WaitGroup
 	Started *atomic.Bool
 	quit    chan struct{}
@@ -75,7 +73,6 @@ func New(
 		ConfirmedBlocksChan:   confirmedBlocksChan,
 		blockHeaderChan:       headersChan,
 		checkpointsChan:       ckptsChan,
-		Synced:                atomic.NewBool(false),
 		Started:               atomic.NewBool(false),
 		quit:                  make(chan struct{}),
 	}, nil
@@ -88,9 +85,6 @@ func (bs *BtcScanner) Start() {
 		return
 	}
 
-	// the bootstrapping should not block the main thread
-	go bs.Bootstrap()
-
 	bs.Started.Store(true)
 	bs.logger.Info("the BTC scanner is started")
 
@@ -99,15 +93,9 @@ func (bs *BtcScanner) Start() {
 		return
 	}
 
-	blockNotifier, err := bs.btcNotifier.RegisterBlockEpochNtfn(nil)
-	if err != nil {
-		bs.logger.Errorf("Failed registering block epoch notifier")
-		return
-	}
-
 	// start handling new blocks
 	bs.wg.Add(1)
-	go bs.blockEventHandler(blockNotifier)
+	go bs.bootstrapAndBlockEventHandler()
 
 	for bs.Started.Load() {
 		select {
@@ -141,12 +129,6 @@ func (bs *BtcScanner) Bootstrap() {
 		err                    error
 	)
 
-	if bs.Synced.Load() {
-		// the scanner is already synced
-		return
-	}
-	defer bs.Synced.Store(true)
-
 	if bs.confirmedTipBlock != nil {
 		firstUnconfirmedHeight = uint64(bs.confirmedTipBlock.Height + 1)
 	} else {

monitor/btcscanner/btc_scanner_test.go

@@ -5,15 +5,13 @@ import (
 	"testing"
 
 	"github.com/babylonlabs-io/babylon/testutil/datagen"
-	"github.com/golang/mock/gomock"
-	"github.com/stretchr/testify/require"
-	"go.uber.org/atomic"
-
 	"github.com/babylonlabs-io/vigilante/config"
 	"github.com/babylonlabs-io/vigilante/monitor/btcscanner"
 	vdatagen "github.com/babylonlabs-io/vigilante/testutil/datagen"
 	"github.com/babylonlabs-io/vigilante/testutil/mocks"
 	"github.com/babylonlabs-io/vigilante/types"
+	"github.com/golang/mock/gomock"
+	"github.com/stretchr/testify/require"
 )
 
 func FuzzBootStrap(f *testing.F) {
@@ -44,7 +42,6 @@ func FuzzBootStrap(f *testing.F) {
 			K:                     k,
 			ConfirmedBlocksChan:   make(chan *types.IndexedBlock),
 			UnconfirmedBlockCache: cache,
-			Synced:                atomic.NewBool(false),
 		}
 		logger, err := config.NewRootLogger("auto", "debug")
 		require.NoError(t, err)
@@ -57,6 +54,5 @@ func FuzzBootStrap(f *testing.F) {
 			}
 		}()
 		btcScanner.Bootstrap()
-		require.True(t, btcScanner.Synced.Load())
 	})
 }