Publish last accepted height through chits

This commit adds the last accepted height to the Chits message.

The intention is that by receiving the latest accepted height of each node,
a node can know whether it is straggling behind the majority of the nodes in the chain.

I ran a build with the commit on a Fuji testnet node and verified the log matches the commit.

```
[10-02|19:59:48.312] VERBO <P Chain> snowman/engine.go:362 called Chits for the block {"nodeID": "NodeID-1AFBjE7UUM1AWWA1HtMGreRrvKwTh9Su", "requestID": 335, "preferredID": "zmoZ2RPy2mkx1ozSbhen9Ggh9boTewBCa6bgc5FnQu7d2umrf", "preferredIDAtHeight": "zmoZ2RPy2mkx1ozSbhen9Ggh9boTewBCa6bgc5FnQu7d2umrf", "acceptedID": "zmoZ2RPy2mkx1ozSbhen9Ggh9boTewBCa6bgc5FnQu7d2umrf", "acceptedHeight": 0}
```

Also verified on its grafana dashboard that it participates in consensus and that there are no failing health checks.

Signed-off-by: Yacov Manevich <yacov.manevich@avalabs.org>

message/outbound_msg_builder.go

@@ -154,6 +154,7 @@ type OutboundMsgBuilder interface {
 		preferredID ids.ID,
 		preferredIDAtHeight ids.ID,
 		acceptedID ids.ID,
+		acceptedHeight uint64,
 	) (OutboundMessage, error)
 
 	AppRequest(
@@ -639,6 +640,7 @@ func (b *outMsgBuilder) Chits(
 	preferredID ids.ID,
 	preferredIDAtHeight ids.ID,
 	acceptedID ids.ID,
+	acceptedHeight uint64,
 ) (OutboundMessage, error) {
 	return b.builder.createOutbound(
 		&p2p.Message{
@@ -649,6 +651,7 @@ func (b *outMsgBuilder) Chits(
 					PreferredId:         preferredID[:],
 					PreferredIdAtHeight: preferredIDAtHeight[:],
 					AcceptedId:          acceptedID[:],
+					AcceptedHeight:      acceptedHeight,
 				},
 			},
 		},

proto/p2p/p2p.proto

@@ -371,6 +371,8 @@ message Chits {
   bytes accepted_id = 4;
   // Currently preferred block at the requested height
   bytes preferred_id_at_height = 5;
+  // Last accepted block's height
+  uint64 accepted_height = 6;
 }
 
 // AppRequest is a VM-defined request.

snow/engine/common/engine.go

@@ -330,6 +330,7 @@ type ChitsHandler interface {
 		preferredID ids.ID,
 		preferredIDAtHeight ids.ID,
 		acceptedID ids.ID,
+		acceptedHeight uint64,
 	) error
 
 	// Notify this engine that a Query request it issued has failed.

snow/engine/common/no_ops_handlers.go

@@ -237,7 +237,7 @@ func NewNoOpChitsHandler(log logging.Logger) ChitsHandler {
 	return &noOpChitsHandler{log: log}
 }
 
-func (nop *noOpChitsHandler) Chits(_ context.Context, nodeID ids.NodeID, requestID uint32, preferredID, preferredIDAtHeight, acceptedID ids.ID) error {
+func (nop *noOpChitsHandler) Chits(_ context.Context, nodeID ids.NodeID, requestID uint32, preferredID, preferredIDAtHeight, acceptedID ids.ID, acceptedHeight uint64) error {
 	nop.log.Debug("dropping request",
 		zap.String("reason", "unhandled by this gear"),
 		zap.Stringer("messageOp", message.ChitsOp),
@@ -246,6 +246,7 @@ func (nop *noOpChitsHandler) Chits(_ context.Context, nodeID ids.NodeID, request
 		zap.Stringer("preferredID", preferredID),
 		zap.Stringer("preferredIDAtHeight", preferredIDAtHeight),
 		zap.Stringer("acceptedID", acceptedID),
+		zap.Uint64("acceptedHeight", acceptedHeight),
 	)
 	return nil
 }

snow/engine/common/sender.go

@@ -161,6 +161,7 @@ type QuerySender interface {
 		preferredID ids.ID,
 		preferredIDAtHeight ids.ID,
 		acceptedID ids.ID,
+		acceptedHeight uint64,
 	)
 }
 

snow/engine/common/traced_engine.go

@@ -245,7 +245,7 @@ func (e *tracedEngine) PushQuery(ctx context.Context, nodeID ids.NodeID, request
 	return e.engine.PushQuery(ctx, nodeID, requestID, container, requestedHeight)
 }
 
-func (e *tracedEngine) Chits(ctx context.Context, nodeID ids.NodeID, requestID uint32, preferredID ids.ID, preferredIDAtHeight ids.ID, acceptedID ids.ID) error {
+func (e *tracedEngine) Chits(ctx context.Context, nodeID ids.NodeID, requestID uint32, preferredID ids.ID, preferredIDAtHeight ids.ID, acceptedID ids.ID, acceptedHeight uint64) error {
 	ctx, span := e.tracer.Start(ctx, "tracedEngine.Chits", oteltrace.WithAttributes(
 		attribute.Stringer("nodeID", nodeID),
 		attribute.Int64("requestID", int64(requestID)),
@@ -255,7 +255,7 @@ func (e *tracedEngine) Chits(ctx context.Context, nodeID ids.NodeID, requestID u
 	))
 	defer span.End()
 
-	return e.engine.Chits(ctx, nodeID, requestID, preferredID, preferredIDAtHeight, acceptedID)
+	return e.engine.Chits(ctx, nodeID, requestID, preferredID, preferredIDAtHeight, acceptedID, acceptedHeight)
 }
 
 func (e *tracedEngine) QueryFailed(ctx context.Context, nodeID ids.NodeID, requestID uint32) error {

snow/engine/common/tracker/accepted.go

@@ -18,22 +18,28 @@ type Accepted interface {
 	validators.SetCallbackListener
 
 	// SetLastAccepted updates the latest accepted block for [nodeID] to
-	// [blockID]. If [nodeID] is not currently a validator, this is a noop.
-	SetLastAccepted(nodeID ids.NodeID, blockID ids.ID)
+	// [blockID], with a corresponding height.
+	// If [nodeID] is not currently a validator, this is a noop.
+	SetLastAccepted(nodeID ids.NodeID, blockID ids.ID, height uint64)
 	// LastAccepted returns the latest known accepted block of [nodeID]. If
 	// [nodeID]'s last accepted block was never unknown, false will be returned.
-	LastAccepted(nodeID ids.NodeID) (ids.ID, bool)
+	LastAccepted(nodeID ids.NodeID) (ids.ID, uint64, bool)
+}
+
+type idHeight struct {
+	id     ids.ID
+	height uint64
 }
 
 type accepted struct {
-	lock       sync.RWMutex
-	validators set.Set[ids.NodeID]
-	frontier   map[ids.NodeID]ids.ID
+	lock         sync.RWMutex
+	validators   set.Set[ids.NodeID]
+	lastAccepted map[ids.NodeID]idHeight
 }
 
 func NewAccepted() Accepted {
 	return &accepted{
-		frontier: make(map[ids.NodeID]ids.ID),
+		lastAccepted: make(map[ids.NodeID]idHeight),
 	}
 }
 
@@ -49,24 +55,27 @@ func (a *accepted) OnValidatorRemoved(nodeID ids.NodeID, _ uint64) {
 	defer a.lock.Unlock()
 
 	a.validators.Remove(nodeID)
-	delete(a.frontier, nodeID)
+	delete(a.lastAccepted, nodeID)
 }
 
 func (*accepted) OnValidatorWeightChanged(_ ids.NodeID, _, _ uint64) {}
 
-func (a *accepted) SetLastAccepted(nodeID ids.NodeID, frontier ids.ID) {
+func (a *accepted) SetLastAccepted(nodeID ids.NodeID, frontier ids.ID, height uint64) {
 	a.lock.Lock()
 	defer a.lock.Unlock()
 
 	if a.validators.Contains(nodeID) {
-		a.frontier[nodeID] = frontier
+		a.lastAccepted[nodeID] = idHeight{
+			id:     frontier,
+			height: height,
+		}
 	}
 }
 
-func (a *accepted) LastAccepted(nodeID ids.NodeID) (ids.ID, bool) {
+func (a *accepted) LastAccepted(nodeID ids.NodeID) (ids.ID, uint64, bool) {
 	a.lock.RLock()
 	defer a.lock.RUnlock()
 
-	acceptedID, ok := a.frontier[nodeID]
-	return acceptedID, ok
+	acceptedAndHeight, ok := a.lastAccepted[nodeID]
+	return acceptedAndHeight.id, acceptedAndHeight.height, ok
 }

snow/engine/common/tracker/accepted_test.go

@@ -20,30 +20,32 @@ func TestAccepted(t *testing.T) {
 
 	a := NewAccepted()
 
-	_, ok := a.LastAccepted(nodeID)
+	_, _, ok := a.LastAccepted(nodeID)
 	require.False(ok)
 
-	a.SetLastAccepted(nodeID, blkID0)
-	_, ok = a.LastAccepted(nodeID)
+	a.SetLastAccepted(nodeID, blkID0, 13)
+	_, _, ok = a.LastAccepted(nodeID)
 	require.False(ok)
 
 	a.OnValidatorAdded(nodeID, nil, ids.GenerateTestID(), 1)
 
-	_, ok = a.LastAccepted(nodeID)
+	_, _, ok = a.LastAccepted(nodeID)
 	require.False(ok)
 
-	a.SetLastAccepted(nodeID, blkID0)
-	blkID, ok := a.LastAccepted(nodeID)
+	a.SetLastAccepted(nodeID, blkID0, 11)
+	blkID, height, ok := a.LastAccepted(nodeID)
 	require.True(ok)
 	require.Equal(blkID0, blkID)
+	require.Equal(uint64(11), height)
 
-	a.SetLastAccepted(nodeID, blkID1)
-	blkID, ok = a.LastAccepted(nodeID)
+	a.SetLastAccepted(nodeID, blkID1, 12)
+	blkID, height, ok = a.LastAccepted(nodeID)
 	require.True(ok)
 	require.Equal(blkID1, blkID)
+	require.Equal(uint64(12), height)
 
 	a.OnValidatorRemoved(nodeID, 1)
 
-	_, ok = a.LastAccepted(nodeID)
+	_, _, ok = a.LastAccepted(nodeID)
 	require.False(ok)
 }