Refactor head info for better usages for lock

beacon-chain/blockchain/chain_info.go

@@ -97,7 +97,10 @@ func (s *Service) PreviousJustifiedCheckpt() *ethpb.Checkpoint {
 
 // HeadSlot returns the slot of the head of the chain.
 func (s *Service) HeadSlot() uint64 {
-	if !s.HasHeadState() {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	if !s.hasHeadState() {
 		return 0
 	}
 
@@ -106,6 +109,9 @@ func (s *Service) HeadSlot() uint64 {
 
 // HeadRoot returns the root of the head of the chain.
 func (s *Service) HeadRoot(ctx context.Context) ([]byte, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if s.headRoot() != params.BeaconConfig().ZeroHash {
 		r := s.headRoot()
 		return r[:], nil
@@ -131,7 +137,10 @@ func (s *Service) HeadRoot(ctx context.Context) ([]byte, error) {
 // If the head is nil from service struct,
 // it will attempt to get the head block from DB.
 func (s *Service) HeadBlock(ctx context.Context) (*ethpb.SignedBeaconBlock, error) {
-	if s.HasHeadState() {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	if s.hasHeadState() {
 		return s.headBlock(), nil
 	}
 
@@ -144,8 +153,10 @@ func (s *Service) HeadBlock(ctx context.Context) (*ethpb.SignedBeaconBlock, erro
 func (s *Service) HeadState(ctx context.Context) (*state.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.HeadState")
 	defer span.End()
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
 
-	ok := s.HasHeadState()
+	ok := s.hasHeadState()
 	span.AddAttributes(trace.BoolAttribute("cache_hit", ok))
 
 	if ok {
@@ -157,15 +168,21 @@ func (s *Service) HeadState(ctx context.Context) (*state.BeaconState, error) {
 
 // HeadValidatorsIndices returns a list of active validator indices from the head view of a given epoch.
 func (s *Service) HeadValidatorsIndices(ctx context.Context, epoch uint64) ([]uint64, error) {
-	if !s.HasHeadState() {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	if !s.hasHeadState() {
 		return []uint64{}, nil
 	}
 	return helpers.ActiveValidatorIndices(s.headState(ctx), epoch)
 }
 
 // HeadSeed returns the seed from the head view of a given epoch.
 func (s *Service) HeadSeed(ctx context.Context, epoch uint64) ([32]byte, error) {
-	if !s.HasHeadState() {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	if !s.hasHeadState() {
 		return [32]byte{}, nil
 	}
 
@@ -174,7 +191,10 @@ func (s *Service) HeadSeed(ctx context.Context, epoch uint64) ([32]byte, error)
 
 // HeadGenesisValidatorRoot returns genesis validator root of the head state.
 func (s *Service) HeadGenesisValidatorRoot() [32]byte {
-	if !s.HasHeadState() {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
+	if !s.hasHeadState() {
 		return [32]byte{}
 	}
 

beacon-chain/blockchain/chain_info_test.go

@@ -103,13 +103,15 @@ func TestHeadSlot_CanRetrieve(t *testing.T) {
 	s, err := state.InitializeFromProto(&pb.BeaconState{})
 	require.NoError(t, err)
 	c.head = &head{slot: 100, state: s}
-	assert.Equal(t, uint64(100), c.headSlot())
+	assert.Equal(t, uint64(100), c.HeadSlot())
 }
 
 func TestHeadRoot_CanRetrieve(t *testing.T) {
 	c := &Service{}
 	c.head = &head{root: [32]byte{'A'}}
-	assert.Equal(t, [32]byte{'A'}, c.headRoot())
+	r, err := c.HeadRoot(context.Background())
+	require.NoError(t, err)
+	assert.Equal(t, [32]byte{'A'}, bytesutil.ToBytes32(r))
 }
 
 func TestHeadBlock_CanRetrieve(t *testing.T) {

beacon-chain/blockchain/head.go

@@ -72,7 +72,11 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 	defer span.End()
 
 	// Do nothing if head hasn't changed.
-	if headRoot == s.headRoot() {
+	r, err := s.HeadRoot(ctx)
+	if err != nil {
+		return err
+	}
+	if headRoot == bytesutil.ToBytes32(r) {
 		return nil
 	}
 
@@ -101,16 +105,17 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 	}
 
 	// A chain re-org occurred, so we fire an event notifying the rest of the services.
-	if bytesutil.ToBytes32(newHeadBlock.Block.ParentRoot) != s.headRoot() {
+	headSlot := s.HeadSlot()
+	if bytesutil.ToBytes32(newHeadBlock.Block.ParentRoot) != bytesutil.ToBytes32(r) {
 		log.WithFields(logrus.Fields{
 			"newSlot": fmt.Sprintf("%d", newHeadBlock.Block.Slot),
-			"oldSlot": fmt.Sprintf("%d", s.headSlot()),
+			"oldSlot": fmt.Sprintf("%d", headSlot),
 		}).Debug("Chain reorg occurred")
 		s.stateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.Reorg,
 			Data: &statefeed.ReorgData{
 				NewSlot: newHeadBlock.Block.Slot,
-				OldSlot: s.headSlot(),
+				OldSlot: headSlot,
 			},
 		})
 
@@ -179,52 +184,42 @@ func (s *Service) setHeadInitialSync(root [32]byte, block *ethpb.SignedBeaconBlo
 }
 
 // This returns the head slot.
+// This is a lock free version.
 func (s *Service) headSlot() uint64 {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
 	return s.head.slot
 }
 
 // This returns the head root.
 // It does a full copy on head root for immutability.
+// This is a lock free version.
 func (s *Service) headRoot() [32]byte {
 	if s.head == nil {
 		return params.BeaconConfig().ZeroHash
 	}
 
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
 	return s.head.root
 }
 
 // This returns the head block.
 // It does a full copy on head block for immutability.
+// This is a lock free version.
 func (s *Service) headBlock() *ethpb.SignedBeaconBlock {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
 	return stateTrie.CopySignedBeaconBlock(s.head.block)
 }
 
 // This returns the head state.
 // It does a full copy on head state for immutability.
+// This is a lock free version.
 func (s *Service) headState(ctx context.Context) *stateTrie.BeaconState {
 	ctx, span := trace.StartSpan(ctx, "blockChain.headState")
 	defer span.End()
 
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
 	return s.head.state.Copy()
 }
 
 // This returns the genesis validator root of the head state.
+// This is a lock free version.
 func (s *Service) headGenesisValidatorRoot() [32]byte {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
 	return bytesutil.ToBytes32(s.head.state.GenesisValidatorRoot())
 }
 

beacon-chain/blockchain/info.go

@@ -34,7 +34,12 @@ const template = `<html>
 
 // TreeHandler is a handler to serve /tree page in metrics.
 func (s *Service) TreeHandler(w http.ResponseWriter, r *http.Request) {
-	if s.headState(r.Context()) == nil {
+	headState, err := s.HeadState(r.Context())
+	if err != nil {
+		log.WithError(err).Error("Could not get head state")
+		return
+	}
+	if headState == nil {
 		if _, err := w.Write([]byte("Unavailable during initial syncing")); err != nil {
 			log.WithError(err).Error("Failed to render p2p info page")
 		}
@@ -47,7 +52,7 @@ func (s *Service) TreeHandler(w http.ResponseWriter, r *http.Request) {
 	graph.Attr("labeljust", "l")
 
 	dotNodes := make([]*dot.Node, len(nodes))
-	avgBalance := uint64(averageBalance(s.headState(r.Context()).Balances()))
+	avgBalance := uint64(averageBalance(headState.Balances()))
 
 	for i := len(nodes) - 1; i >= 0; i-- {
 		// Construct label for each node.
@@ -63,7 +68,7 @@ func (s *Service) TreeHandler(w http.ResponseWriter, r *http.Request) {
 			dotN = graph.Node(index).Box().Attr("label", label)
 		}
 
-		if nodes[i].Slot() == s.headSlot() &&
+		if nodes[i].Slot() == s.HeadSlot() &&
 			nodes[i].BestDescendant() == ^uint64(0) &&
 			nodes[i].Parent() != ^uint64(0) {
 			dotN = dotN.Attr("color", "green")

beacon-chain/blockchain/receive_block.go

@@ -59,7 +59,7 @@ func (s *Service) ReceiveBlock(ctx context.Context, block *ethpb.SignedBeaconBlo
 	}
 
 	// Reports on block and fork choice metrics.
-	reportSlotMetrics(blockCopy.Block.Slot, s.headSlot(), s.CurrentSlot(), s.finalizedCheckpt)
+	reportSlotMetrics(blockCopy.Block.Slot, s.HeadSlot(), s.CurrentSlot(), s.finalizedCheckpt)
 
 	// Log block sync status.
 	logBlockSyncStatus(blockCopy.Block, blockRoot, s.finalizedCheckpt)
@@ -95,7 +95,7 @@ func (s *Service) ReceiveBlockInitialSync(ctx context.Context, block *ethpb.Sign
 	})
 
 	// Reports on blockCopy and fork choice metrics.
-	reportSlotMetrics(blockCopy.Block.Slot, s.headSlot(), s.CurrentSlot(), s.finalizedCheckpt)
+	reportSlotMetrics(blockCopy.Block.Slot, s.HeadSlot(), s.CurrentSlot(), s.finalizedCheckpt)
 
 	// Log state transition data.
 	log.WithFields(logrus.Fields{
@@ -139,7 +139,7 @@ func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []*ethpb.SignedB
 		})
 
 		// Reports on blockCopy and fork choice metrics.
-		reportSlotMetrics(blockCopy.Block.Slot, s.headSlot(), s.CurrentSlot(), s.finalizedCheckpt)
+		reportSlotMetrics(blockCopy.Block.Slot, s.HeadSlot(), s.CurrentSlot(), s.finalizedCheckpt)
 	}
 
 	if err := s.VerifyWeakSubjectivityRoot(s.ctx); err != nil {

beacon-chain/blockchain/service_test.go

@@ -218,7 +218,9 @@ func TestChainService_InitializeBeaconChain(t *testing.T) {
 	if headBlk == nil {
 		t.Error("Head state can't be nil after initialize beacon chain")
 	}
-	if bc.headRoot() == params.BeaconConfig().ZeroHash {
+	r, err := bc.HeadRoot(ctx)
+	require.NoError(t, err)
+	if bytesutil.ToBytes32(r) == params.BeaconConfig().ZeroHash {
 		t.Error("Canonical root for slot 0 can't be zeros after initialize beacon chain")
 	}
 }

beacon-chain/main.go

@@ -19,9 +19,9 @@ import (
 	_ "github.com/prysmaticlabs/prysm/shared/maxprocs"
 	"github.com/prysmaticlabs/prysm/shared/version"
 	"github.com/sirupsen/logrus"
-	"github.com/wercker/journalhook"
 	"github.com/urfave/cli/v2"
 	"github.com/urfave/cli/v2/altsrc"
+	"github.com/wercker/journalhook"
 	prefixed "github.com/x-cray/logrus-prefixed-formatter"
 )
 

slasher/main.go

@@ -17,9 +17,9 @@ import (
 	"github.com/prysmaticlabs/prysm/slasher/flags"
 	"github.com/prysmaticlabs/prysm/slasher/node"
 	"github.com/sirupsen/logrus"
-	"github.com/wercker/journalhook"
 	"github.com/urfave/cli/v2"
 	"github.com/urfave/cli/v2/altsrc"
+	"github.com/wercker/journalhook"
 	prefixed "github.com/x-cray/logrus-prefixed-formatter"
 )
 

validator/main.go

@@ -27,9 +27,9 @@ import (
 	"github.com/prysmaticlabs/prysm/validator/flags"
 	"github.com/prysmaticlabs/prysm/validator/node"
 	"github.com/sirupsen/logrus"
-	"github.com/wercker/journalhook"
 	"github.com/urfave/cli/v2"
 	"github.com/urfave/cli/v2/altsrc"
+	"github.com/wercker/journalhook"
 	prefixed "github.com/x-cray/logrus-prefixed-formatter"
 	"google.golang.org/grpc"
 )