blockchain/v0: relax termination conditions and increase sync timeout (#5741)

Closes: #5718
2026-01-05 21:14:53 +00:00 · 2020-12-08 11:33:03 +04:00
parent 8e80c26e80
commit 89e908e340
6 changed files with 170 additions and 131 deletions
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -37,6 +37,7 @@ Friendly reminder, we have a [bug bounty program](https://hackerone.com/tendermi
 - [mempool] \#5673 Cancel `CheckTx` requests if RPC client disconnects or times out (@melekes)
 - [abci] \#5706 Added `AbciVersion` to `RequestInfo` allowing applications to check ABCI version when connecting to Tendermint. (@marbar3778)
 - [blockchain/v1] \#5728 Remove in favor of v2 (@melekes)
+- [blockchain/v0] \#5741 Relax termination conditions and increase sync timeout (@melekes)

 ### BUG FIXES

--- a/blockchain/doc.go
+++ b/blockchain/doc.go
@@ -0,0 +1,17 @@
+/*
+Package blockchain provides two implementations of the fast-sync protocol.
+
+- v0 was the very first implementation. it's battle tested, but does not have a
+lot of test coverage.
+- v2 is the newest implementation, with a focus on testability and readability.
+
+Check out ADR-40 for the formal model and requirements.
+
+# Termination criteria
+
+1. the maximum peer height is reached
+2. termination timeout is triggered, which is set if the peer set is empty or
+there are no pending requests.
+
+*/
+package blockchain
--- a/blockchain/v0/pool.go
+++ b/blockchain/v0/pool.go
@@ -58,12 +58,19 @@ var peerTimeout = 15 * time.Second // not const so we can override with tests
 	are not at peer limits, we can probably switch to consensus reactor
 */

+// BlockRequest stores a block request identified by the block Height and the
+// PeerID responsible for delivering the block.
+type BlockRequest struct {
+	Height int64
+	PeerID p2p.ID
+}
+
 // BlockPool keeps track of the fast sync peers, block requests and block responses.
 type BlockPool struct {
 	service.BaseService
-	startTime time.Time
+	lastAdvance time.Time

-	mtx tmsync.Mutex
+	mtx tmsync.RWMutex
 	// block requests
 	requesters map[int64]*bpRequester
 	height     int64 // the lowest key in requesters.
@@ -98,8 +105,8 @@ func NewBlockPool(start int64, requestsCh chan<- BlockRequest, errorsCh chan<- p
 // OnStart implements service.Service by spawning requesters routine and recording
 // pool's start time.
 func (pool *BlockPool) OnStart() error {
+	pool.lastAdvance = time.Now()
 	go pool.makeRequestersRoutine()
-	pool.startTime = time.Now()
 	return nil
 }

@@ -134,6 +141,7 @@ func (pool *BlockPool) removeTimedoutPeers() {
 	defer pool.mtx.Unlock()

 	for _, peer := range pool.peers {
+		// check if peer timed out
 		if !peer.didTimeout && peer.numPending > 0 {
 			curRate := peer.recvMonitor.Status().CurRate
 			// curRate can be 0 on start
@@ -147,6 +155,7 @@ func (pool *BlockPool) removeTimedoutPeers() {
 				peer.didTimeout = true
 			}
 		}
+
 		if peer.didTimeout {
 			pool.removePeer(peer.id)
 		}
@@ -156,33 +165,24 @@ func (pool *BlockPool) removeTimedoutPeers() {
 // GetStatus returns pool's height, numPending requests and the number of
 // requesters.
 func (pool *BlockPool) GetStatus() (height int64, numPending int32, lenRequesters int) {
-	pool.mtx.Lock()
-	defer pool.mtx.Unlock()
+	pool.mtx.RLock()
+	defer pool.mtx.RUnlock()

 	return pool.height, atomic.LoadInt32(&pool.numPending), len(pool.requesters)
 }

 // IsCaughtUp returns true if this node is caught up, false - otherwise.
-// TODO: relax conditions, prevent abuse.
 func (pool *BlockPool) IsCaughtUp() bool {
-	pool.mtx.Lock()
-	defer pool.mtx.Unlock()
+	pool.mtx.RLock()
+	defer pool.mtx.RUnlock()

 	// Need at least 1 peer to be considered caught up.
 	if len(pool.peers) == 0 {
-		pool.Logger.Debug("Blockpool has no peers")
 		return false
 	}
-
-	// Some conditions to determine if we're caught up.
-	// Ensures we've either received a block or waited some amount of time,
-	// and that we're synced to the highest known height.
-	// Note we use maxPeerHeight - 1 because to sync block H requires block H+1
+	// NOTE: we use maxPeerHeight - 1 because to sync block H requires block H+1
 	// to verify the LastCommit.
-	receivedBlockOrTimedOut := pool.height > 0 || time.Since(pool.startTime) > 5*time.Second
-	ourChainIsLongestAmongPeers := pool.maxPeerHeight == 0 || pool.height >= (pool.maxPeerHeight-1)
-	isCaughtUp := receivedBlockOrTimedOut && ourChainIsLongestAmongPeers
-	return isCaughtUp
+	return pool.height >= (pool.maxPeerHeight - 1)
 }

 // PeekTwoBlocks returns blocks at pool.height and pool.height+1.
@@ -190,8 +190,8 @@ func (pool *BlockPool) IsCaughtUp() bool {
 // So we peek two blocks at a time.
 // The caller will verify the commit.
 func (pool *BlockPool) PeekTwoBlocks() (first *types.Block, second *types.Block) {
-	pool.mtx.Lock()
-	defer pool.mtx.Unlock()
+	pool.mtx.RLock()
+	defer pool.mtx.RUnlock()

 	if r := pool.requesters[pool.height]; r != nil {
 		first = r.getBlock()
@@ -209,16 +209,12 @@ func (pool *BlockPool) PopRequest() {
 	defer pool.mtx.Unlock()

 	if r := pool.requesters[pool.height]; r != nil {
-		/*  The block can disappear at any time, due to removePeer().
-		if r := pool.requesters[pool.height]; r == nil || r.block == nil {
-			PanicSanity("PopRequest() requires a valid block")
-		}
-		*/
 		if err := r.Stop(); err != nil {
 			pool.Logger.Error("Error stopping requester", "err", err)
 		}
 		delete(pool.requesters, pool.height)
 		pool.height++
+		pool.lastAdvance = time.Now()
 	} else {
 		panic(fmt.Sprintf("Expected requester to pop, got nothing at height %v", pool.height))
 	}
@@ -248,14 +244,8 @@ func (pool *BlockPool) AddBlock(peerID p2p.ID, block *types.Block, blockSize int

 	requester := pool.requesters[block.Height]
 	if requester == nil {
-		pool.Logger.Info(
-			"peer sent us a block we didn't expect",
-			"peer",
-			peerID,
-			"curHeight",
-			pool.height,
-			"blockHeight",
-			block.Height)
+		pool.Logger.Error("peer sent us a block we didn't expect",
+			"peer", peerID, "curHeight", pool.height, "blockHeight", block.Height)
 		diff := pool.height - block.Height
 		if diff < 0 {
 			diff *= -1
@@ -273,18 +263,27 @@ func (pool *BlockPool) AddBlock(peerID p2p.ID, block *types.Block, blockSize int
 			peer.decrPending(blockSize)
 		}
 	} else {
-		pool.Logger.Info("invalid peer", "peer", peerID, "blockHeight", block.Height)
-		pool.sendError(errors.New("invalid peer"), peerID)
+		err := errors.New("requester is different or block already exists")
+		pool.Logger.Error(err.Error(), "peer", peerID, "requester", requester.getPeerID(), "blockHeight", block.Height)
+		pool.sendError(err, peerID)
 	}
 }

 // MaxPeerHeight returns the highest reported height.
 func (pool *BlockPool) MaxPeerHeight() int64 {
-	pool.mtx.Lock()
-	defer pool.mtx.Unlock()
+	pool.mtx.RLock()
+	defer pool.mtx.RUnlock()
 	return pool.maxPeerHeight
 }

+// LastAdvance returns the time when the last block was processed (or start
+// time if no blocks were processed).
+func (pool *BlockPool) LastAdvance() time.Time {
+	pool.mtx.RLock()
+	defer pool.mtx.RUnlock()
+	return pool.lastAdvance
+}
+
 // SetPeerRange sets the peer's alleged blockchain base and height.
 func (pool *BlockPool) SetPeerRange(peerID p2p.ID, base int64, height int64) {
 	pool.mtx.Lock()
@@ -601,7 +600,6 @@ OUTER_LOOP:
 			}
 			peer = bpr.pool.pickIncrAvailablePeer(bpr.height)
 			if peer == nil {
-				// log.Info("No peers available", "height", height)
 				time.Sleep(requestIntervalMS * time.Millisecond)
 				continue PICK_PEER_LOOP
 			}
@@ -638,10 +636,3 @@ OUTER_LOOP:
 		}
 	}
 }
-
-// BlockRequest stores a block request identified by the block Height and the PeerID responsible for
-// delivering the block
-type BlockRequest struct {
-	Height int64
-	PeerID p2p.ID
-}
--- a/blockchain/v0/reactor.go
+++ b/blockchain/v0/reactor.go
@@ -28,6 +28,9 @@ const (
 	statusUpdateIntervalSeconds = 10
 	// check if we should switch to consensus reactor
 	switchToConsensusIntervalSeconds = 1
+
+	// switch to consensus after this duration of inactivity
+	syncTimeout = 60 * time.Second
 )

 type consensusReactor interface {
@@ -158,7 +161,7 @@ func (bcR *BlockchainReactor) AddPeer(peer p2p.Peer) {
 		return
 	}

-	peer.Send(BlockchainChannel, msgBytes)
+	_ = peer.Send(BlockchainChannel, msgBytes)
 	// it's OK if send fails. will try later in poolRoutine

 	// peer is added to the pool once we receive the first
@@ -207,20 +210,22 @@ func (bcR *BlockchainReactor) respondToPeer(msg *bcproto.BlockRequest,
 // XXX: do not call any methods that can block or incur heavy processing.
 // https://github.com/tendermint/tendermint/issues/2888
 func (bcR *BlockchainReactor) Receive(chID byte, src p2p.Peer, msgBytes []byte) {
+	logger := bcR.Logger.With("src", src, "chId", chID)
+
 	msg, err := bc.DecodeMsg(msgBytes)
 	if err != nil {
-		bcR.Logger.Error("Error decoding message", "src", src, "chId", chID, "err", err)
+		logger.Error("Error decoding message", "err", err)
 		bcR.Switch.StopPeerForError(src, err)
 		return
 	}

 	if err = bc.ValidateMsg(msg); err != nil {
-		bcR.Logger.Error("Peer sent us invalid msg", "peer", src, "msg", msg, "err", err)
+		logger.Error("Peer sent us invalid msg", "msg", msg, "err", err)
 		bcR.Switch.StopPeerForError(src, err)
 		return
 	}

-	bcR.Logger.Debug("Receive", "src", src, "chID", chID, "msg", msg)
+	logger.Debug("Receive", "msg", msg)

 	switch msg := msg.(type) {
 	case *bcproto.BlockRequest:
@@ -228,7 +233,7 @@ func (bcR *BlockchainReactor) Receive(chID byte, src p2p.Peer, msgBytes []byte)
 	case *bcproto.BlockResponse:
 		bi, err := types.BlockFromProto(msg.Block)
 		if err != nil {
-			bcR.Logger.Error("Block content is invalid", "err", err)
+			logger.Error("Block content is invalid", "err", err)
 			bcR.Switch.StopPeerForError(src, err)
 			return
 		}
@@ -240,7 +245,7 @@ func (bcR *BlockchainReactor) Receive(chID byte, src p2p.Peer, msgBytes []byte)
 			Base:   bcR.store.Base(),
 		})
 		if err != nil {
-			bcR.Logger.Error("could not convert msg to protobut", "err", err)
+			logger.Error("could not convert msg to protobut", "err", err)
 			return
 		}
 		src.TrySend(BlockchainChannel, msgBytes)
@@ -248,45 +253,50 @@ func (bcR *BlockchainReactor) Receive(chID byte, src p2p.Peer, msgBytes []byte)
 		// Got a peer status. Unverified.
 		bcR.pool.SetPeerRange(src.ID(), msg.Base, msg.Height)
 	case *bcproto.NoBlockResponse:
-		bcR.Logger.Debug("Peer does not have requested block", "peer", src, "height", msg.Height)
+		logger.Debug("Peer does not have requested block", "height", msg.Height)
 	default:
-		bcR.Logger.Error(fmt.Sprintf("Unknown message type %v", reflect.TypeOf(msg)))
+		logger.Error(fmt.Sprintf("Unknown message type %v", reflect.TypeOf(msg)))
 	}
 }

 // Handle messages from the poolReactor telling the reactor what to do.
 // NOTE: Don't sleep in the FOR_LOOP or otherwise slow it down!
 func (bcR *BlockchainReactor) poolRoutine(stateSynced bool) {
+	var (
+		trySyncTicker           = time.NewTicker(trySyncIntervalMS * time.Millisecond)
+		statusUpdateTicker      = time.NewTicker(statusUpdateIntervalSeconds * time.Second)
+		switchToConsensusTicker = time.NewTicker(switchToConsensusIntervalSeconds * time.Second)

-	trySyncTicker := time.NewTicker(trySyncIntervalMS * time.Millisecond)
-	statusUpdateTicker := time.NewTicker(statusUpdateIntervalSeconds * time.Second)
-	switchToConsensusTicker := time.NewTicker(switchToConsensusIntervalSeconds * time.Second)
+		blocksSynced = uint64(0)

-	blocksSynced := uint64(0)
+		chainID = bcR.initialState.ChainID
+		state   = bcR.initialState

-	chainID := bcR.initialState.ChainID
-	state := bcR.initialState
+		lastHundred = time.Now()
+		lastRate    = 0.0

-	lastHundred := time.Now()
-	lastRate := 0.0
-
-	didProcessCh := make(chan struct{}, 1)
+		didProcessCh = make(chan struct{}, 1)
+	)

 	go func() {
 		for {
 			select {
+
 			case <-bcR.Quit():
 				return
+
 			case <-bcR.pool.Quit():
 				return
+
 			case request := <-bcR.requestsCh:
 				peer := bcR.Switch.Peers().Get(request.PeerID)
 				if peer == nil {
+					bcR.Logger.Debug("Can't send request: no peer", "peer_id", request.PeerID)
 					continue
 				}
 				msgBytes, err := bc.EncodeMsg(&bcproto.BlockRequest{Height: request.Height})
 				if err != nil {
-					bcR.Logger.Error("could not convert msg to proto", "err", err)
+					bcR.Logger.Error("could not convert BlockRequest to proto", "err", err)
 					continue
 				}

@@ -294,6 +304,7 @@ func (bcR *BlockchainReactor) poolRoutine(stateSynced bool) {
 				if !queued {
 					bcR.Logger.Debug("Send queue is full, drop block request", "peer", peer.ID(), "height", request.Height)
 				}
+
 			case err := <-bcR.errorsCh:
 				peer := bcR.Switch.Peers().Get(err.peerID)
 				if peer != nil {
@@ -302,8 +313,7 @@ func (bcR *BlockchainReactor) poolRoutine(stateSynced bool) {

 			case <-statusUpdateTicker.C:
 				// ask for status updates
-				go bcR.BroadcastStatusRequest() // nolint: errcheck
-
+				go bcR.BroadcastStatusRequest()
 			}
 		}
 	}()
@@ -311,27 +321,41 @@ func (bcR *BlockchainReactor) poolRoutine(stateSynced bool) {
 FOR_LOOP:
 	for {
 		select {
-		case <-switchToConsensusTicker.C:
-			height, numPending, lenRequesters := bcR.pool.GetStatus()
-			outbound, inbound, _ := bcR.Switch.NumPeers()
-			bcR.Logger.Debug("Consensus ticker", "numPending", numPending, "total", lenRequesters,
-				"outbound", outbound, "inbound", inbound)
-			if bcR.pool.IsCaughtUp() {
-				bcR.Logger.Info("Time to switch to consensus reactor!", "height", height)
-				if err := bcR.pool.Stop(); err != nil {
-					bcR.Logger.Error("Error stopping pool", "err", err)
-				}
-				conR, ok := bcR.Switch.Reactor("CONSENSUS").(consensusReactor)
-				if ok {
-					conR.SwitchToConsensus(state, blocksSynced > 0 || stateSynced)
-				}
-				// else {
-				// should only happen during testing
-				// }

-				break FOR_LOOP
+		case <-switchToConsensusTicker.C:
+			var (
+				height, numPending, lenRequesters = bcR.pool.GetStatus()
+				outbound, inbound, _              = bcR.Switch.NumPeers()
+				lastAdvance                       = bcR.pool.LastAdvance()
+			)
+
+			bcR.Logger.Debug("Consensus ticker",
+				"numPending", numPending,
+				"total", lenRequesters)
+
+			switch {
+			case bcR.pool.IsCaughtUp():
+				bcR.Logger.Info("Time to switch to consensus reactor!", "height", height)
+			case time.Since(lastAdvance) > syncTimeout:
+				bcR.Logger.Error(fmt.Sprintf("No progress since last advance: %v", lastAdvance))
+			default:
+				bcR.Logger.Info("Not caught up yet",
+					"height", height, "max_peer_height", bcR.pool.MaxPeerHeight(),
+					"num_peers", outbound+inbound,
+					"timeout_in", syncTimeout-time.Since(lastAdvance))
+				continue
 			}

+			if err := bcR.pool.Stop(); err != nil {
+				bcR.Logger.Error("Error stopping pool", "err", err)
+			}
+			conR, ok := bcR.Switch.Reactor("CONSENSUS").(consensusReactor)
+			if ok {
+				conR.SwitchToConsensus(state, blocksSynced > 0 || stateSynced)
+			}
+
+			break FOR_LOOP
+
 		case <-trySyncTicker.C: // chan time
 			select {
 			case didProcessCh <- struct{}{}:
@@ -358,31 +382,37 @@ FOR_LOOP:
 				didProcessCh <- struct{}{}
 			}

-			firstParts := first.MakePartSet(types.BlockPartSizeBytes)
-			firstPartSetHeader := firstParts.Header()
-			firstID := types.BlockID{Hash: first.Hash(), PartSetHeader: firstPartSetHeader}
+			var (
+				firstParts         = first.MakePartSet(types.BlockPartSizeBytes)
+				firstPartSetHeader = firstParts.Header()
+				firstID            = types.BlockID{Hash: first.Hash(), PartSetHeader: firstPartSetHeader}
+			)
+
 			// Finally, verify the first block using the second's commit
 			// NOTE: we can probably make this more efficient, but note that calling
 			// first.Hash() doesn't verify the tx contents, so MakePartSet() is
 			// currently necessary.
-			err := state.Validators.VerifyCommitLight(
-				chainID, firstID, first.Height, second.LastCommit)
+			err := state.Validators.VerifyCommitLight(chainID, firstID, first.Height, second.LastCommit)
 			if err != nil {
-				bcR.Logger.Error("Error in validation", "err", err)
+				err = fmt.Errorf("invalid last commit: %w", err)
+				bcR.Logger.Error(err.Error(),
+					"last_commit", second.LastCommit, "block_id", firstID, "height", first.Height)
+
 				peerID := bcR.pool.RedoRequest(first.Height)
 				peer := bcR.Switch.Peers().Get(peerID)
 				if peer != nil {
-					// NOTE: we've already removed the peer's request, but we
-					// still need to clean up the rest.
-					bcR.Switch.StopPeerForError(peer, fmt.Errorf("blockchainReactor validation error: %v", err))
+					// NOTE: we've already removed the peer's request, but we still need
+					// to clean up the rest.
+					bcR.Switch.StopPeerForError(peer, err)
 				}
+
 				peerID2 := bcR.pool.RedoRequest(second.Height)
-				peer2 := bcR.Switch.Peers().Get(peerID2)
-				if peer2 != nil && peer2 != peer {
-					// NOTE: we've already removed the peer's request, but we
-					// still need to clean up the rest.
-					bcR.Switch.StopPeerForError(peer2, fmt.Errorf("blockchainReactor validation error: %v", err))
+				if peerID2 != peerID {
+					if peer2 := bcR.Switch.Peers().Get(peerID2); peer2 != nil {
+						bcR.Switch.StopPeerForError(peer2, err)
+					}
 				}
+
 				continue FOR_LOOP
 			} else {
 				bcR.pool.PopRequest()
@@ -390,8 +420,8 @@ FOR_LOOP:
 				// TODO: batch saves so we dont persist to disk every block
 				bcR.store.SaveBlock(first, firstParts, second.LastCommit)

-				// TODO: same thing for app - but we would need a way to
-				// get the hash without persisting the state
+				// TODO: same thing for app - but we would need a way to get the hash
+				// without persisting the state.
 				var err error
 				state, _, err = bcR.blockExec.ApplyBlock(state, firstID, first)
 				if err != nil {
@@ -402,8 +432,8 @@ FOR_LOOP:

 				if blocksSynced%100 == 0 {
 					lastRate = 0.9*lastRate + 0.1*(100/time.Since(lastHundred).Seconds())
-					bcR.Logger.Info("Fast Sync Rate", "height", bcR.pool.height,
-						"max_peer_height", bcR.pool.MaxPeerHeight(), "blocks/s", lastRate)
+					bcR.Logger.Info("Fast Sync Rate",
+						"height", bcR.pool.height, "max_peer_height", bcR.pool.MaxPeerHeight(), "blocks/s", lastRate)
 					lastHundred = time.Now()
 				}
 			}
@@ -416,14 +446,13 @@ FOR_LOOP:
 }

 // BroadcastStatusRequest broadcasts `BlockStore` base and height.
-func (bcR *BlockchainReactor) BroadcastStatusRequest() error {
+func (bcR *BlockchainReactor) BroadcastStatusRequest() {
 	bm, err := bc.EncodeMsg(&bcproto.StatusRequest{})
 	if err != nil {
-		bcR.Logger.Error("could not convert msg to proto", "err", err)
-		return fmt.Errorf("could not convert msg to proto: %w", err)
+		bcR.Logger.Error("could not convert StatusRequest to proto", "err", err)
+		return
 	}

-	bcR.Switch.Broadcast(BlockchainChannel, bm)
-
-	return nil
+	// We don't care about whenever broadcast is successful or not.
+	_ = bcR.Switch.Broadcast(BlockchainChannel, bm)
 }
--- a/blockchain/v2/io.go
+++ b/blockchain/v2/io.go
@@ -1,7 +1,7 @@
 package v2

 import (
-	"fmt"
+	"errors"

 	bc "github.com/tendermint/tendermint/blockchain"
 	"github.com/tendermint/tendermint/p2p"
@@ -10,6 +10,11 @@ import (
 	"github.com/tendermint/tendermint/types"
 )

+var (
+	errPeerQueueFull = errors.New("peer queue full")
+	errNoPeer        = errors.New("peer not found")
+)
+
 type iIO interface {
 	sendBlockRequest(peerID p2p.ID, height int64) error
 	sendBlockToPeer(block *types.Block, peerID p2p.ID) error
@@ -45,7 +50,7 @@ type consensusReactor interface {
 func (sio *switchIO) sendBlockRequest(peerID p2p.ID, height int64) error {
 	peer := sio.sw.Peers().Get(peerID)
 	if peer == nil {
-		return fmt.Errorf("peer not found")
+		return errNoPeer
 	}
 	msgBytes, err := bc.EncodeMsg(&bcproto.BlockRequest{Height: height})
 	if err != nil {
@@ -54,7 +59,7 @@ func (sio *switchIO) sendBlockRequest(peerID p2p.ID, height int64) error {

 	queued := peer.TrySend(BlockchainChannel, msgBytes)
 	if !queued {
-		return fmt.Errorf("send queue full")
+		return errPeerQueueFull
 	}
 	return nil
 }
@@ -62,7 +67,7 @@ func (sio *switchIO) sendBlockRequest(peerID p2p.ID, height int64) error {
 func (sio *switchIO) sendStatusResponse(base int64, height int64, peerID p2p.ID) error {
 	peer := sio.sw.Peers().Get(peerID)
 	if peer == nil {
-		return fmt.Errorf("peer not found")
+		return errNoPeer
 	}

 	msgBytes, err := bc.EncodeMsg(&bcproto.StatusResponse{Height: height, Base: base})
@@ -71,7 +76,7 @@ func (sio *switchIO) sendStatusResponse(base int64, height int64, peerID p2p.ID)
 	}

 	if queued := peer.TrySend(BlockchainChannel, msgBytes); !queued {
-		return fmt.Errorf("peer queue full")
+		return errPeerQueueFull
 	}

 	return nil
@@ -80,7 +85,7 @@ func (sio *switchIO) sendStatusResponse(base int64, height int64, peerID p2p.ID)
 func (sio *switchIO) sendBlockToPeer(block *types.Block, peerID p2p.ID) error {
 	peer := sio.sw.Peers().Get(peerID)
 	if peer == nil {
-		return fmt.Errorf("peer not found")
+		return errNoPeer
 	}
 	if block == nil {
 		panic("trying to send nil block")
@@ -96,7 +101,7 @@ func (sio *switchIO) sendBlockToPeer(block *types.Block, peerID p2p.ID) error {
 		return err
 	}
 	if queued := peer.TrySend(BlockchainChannel, msgBytes); !queued {
-		return fmt.Errorf("peer queue full")
+		return errPeerQueueFull
 	}

 	return nil
@@ -105,7 +110,7 @@ func (sio *switchIO) sendBlockToPeer(block *types.Block, peerID p2p.ID) error {
 func (sio *switchIO) sendBlockNotFound(height int64, peerID p2p.ID) error {
 	peer := sio.sw.Peers().Get(peerID)
 	if peer == nil {
-		return fmt.Errorf("peer not found")
+		return errNoPeer
 	}
 	msgBytes, err := bc.EncodeMsg(&bcproto.NoBlockResponse{Height: height})
 	if err != nil {
@@ -113,7 +118,7 @@ func (sio *switchIO) sendBlockNotFound(height int64, peerID p2p.ID) error {
 	}

 	if queued := peer.TrySend(BlockchainChannel, msgBytes); !queued {
-		return fmt.Errorf("peer queue full")
+		return errPeerQueueFull
 	}

 	return nil
--- a/blockchain/v2/reactor.go
+++ b/blockchain/v2/reactor.go
@@ -47,11 +47,6 @@ type BlockchainReactor struct {
 	store    blockStore
 }

-//nolint:unused,deadcode
-type blockVerifier interface {
-	VerifyCommit(chainID string, blockID types.BlockID, height int64, commit *types.Commit) error
-}
-
 type blockApplier interface {
 	ApplyBlock(state state.State, blockID types.BlockID, block *types.Block) (state.State, int64, error)
 }
@@ -458,39 +453,40 @@ func (r *BlockchainReactor) Stop() error {
 // XXX: do not call any methods that can block or incur heavy processing.
 // https://github.com/tendermint/tendermint/issues/2888
 func (r *BlockchainReactor) Receive(chID byte, src p2p.Peer, msgBytes []byte) {
+	logger := r.logger.With("src", src.ID(), "chID", chID)
+
 	msg, err := bc.DecodeMsg(msgBytes)
 	if err != nil {
-		r.logger.Error("error decoding message",
-			"src", src.ID(), "chId", chID, "msg", msg, "err", err)
+		logger.Error("error decoding message", "err", err)
 		_ = r.reporter.Report(behaviour.BadMessage(src.ID(), err.Error()))
 		return
 	}

 	if err = bc.ValidateMsg(msg); err != nil {
-		r.logger.Error("peer sent us invalid msg", "peer", src, "msg", msg, "err", err)
+		logger.Error("peer sent us invalid msg", "msg", msg, "err", err)
 		_ = r.reporter.Report(behaviour.BadMessage(src.ID(), err.Error()))
 		return
 	}

-	r.logger.Debug("Receive", "src", src.ID(), "chID", chID, "msg", msg)
+	r.logger.Debug("Receive", "msg", msg)

 	switch msg := msg.(type) {
 	case *bcproto.StatusRequest:
 		if err := r.io.sendStatusResponse(r.store.Base(), r.store.Height(), src.ID()); err != nil {
-			r.logger.Error("Could not send status message to peer", "src", src)
+			logger.Error("Could not send status message to src peer")
 		}

 	case *bcproto.BlockRequest:
 		block := r.store.LoadBlock(msg.Height)
 		if block != nil {
 			if err = r.io.sendBlockToPeer(block, src.ID()); err != nil {
-				r.logger.Error("Could not send block message to peer: ", err)
+				logger.Error("Could not send block message to src peer", "err", err)
 			}
 		} else {
-			r.logger.Info("peer asking for a block we don't have", "src", src, "height", msg.Height)
+			logger.Info("peer asking for a block we don't have", "height", msg.Height)
 			peerID := src.ID()
 			if err = r.io.sendBlockNotFound(msg.Height, peerID); err != nil {
-				r.logger.Error("Couldn't send block not found: ", err)
+				logger.Error("Couldn't send block not found msg", "err", err)
 			}
 		}

@@ -505,7 +501,7 @@ func (r *BlockchainReactor) Receive(chID byte, src p2p.Peer, msgBytes []byte) {
 		r.mtx.RLock()
 		bi, err := types.BlockFromProto(msg.Block)
 		if err != nil {
-			r.logger.Error("error transitioning block from protobuf", "err", err)
+			logger.Error("error transitioning block from protobuf", "err", err)
 			_ = r.reporter.Report(behaviour.BadMessage(src.ID(), err.Error()))
 			return
 		}