Beacon Node Determines Slot From Genesis Block if ChainState Detected (#606)

beacon-chain/blockchain/service.go

@@ -61,7 +61,6 @@ func NewChainService(ctx context.Context, cfg *Config) (*ChainService, error) {
 	ctx, cancel := context.WithCancel(ctx)
 	return &ChainService{
 		ctx:                            ctx,
-		genesisTimestamp:               params.GetConfig().GenesisTime,
 		chain:                          cfg.Chain,
 		cancel:                         cancel,
 		beaconDB:                       cfg.BeaconDB,
@@ -85,6 +84,15 @@ func (c *ChainService) Start() {
 	// to truly continue across sessions.
 	log.Info("Starting service")
 
+	genesis, err := c.GenesisBlock()
+	if err != nil {
+		log.Fatalf("Could not get genesis block: %v", err)
+	}
+	c.genesisTimestamp, err = genesis.Timestamp()
+	if err != nil {
+		log.Fatalf("Could not get genesis timestamp: %v", err)
+	}
+
 	// If the genesis time was at 12:00:00PM and the current time is 12:00:03PM,
 	// the next slot should tick at 12:00:08PM. We can accomplish this
 	// using utils.BlockingWait and passing in the desired
@@ -373,7 +381,14 @@ func (c *ChainService) blockProcessing() {
 			aState := c.chain.ActiveState()
 			cState := c.chain.CrystallizedState()
 
-			if valid := block.IsValid(c, aState, cState, parent.SlotNumber(), c.enableAttestationValidity); !valid {
+			if valid := block.IsValid(
+				c,
+				aState,
+				cState,
+				parent.SlotNumber(),
+				c.enableAttestationValidity,
+				c.genesisTimestamp,
+			); !valid {
 				log.Debugf("Block failed validity conditions: %v", err)
 				continue
 			}

beacon-chain/rpc/BUILD.bazel

@@ -13,7 +13,6 @@ go_library(
         "//proto/beacon/rpc/v1:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_ethereum_go_ethereum//event:go_default_library",
-        "@com_github_golang_protobuf//ptypes:go_default_library_gen",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@io_bazel_rules_go//proto/wkt:empty_go_proto",
         "@org_golang_google_grpc//:go_default_library",

beacon-chain/rpc/service.go

@@ -11,7 +11,6 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/event"
-	"github.com/golang/protobuf/ptypes"
 	"github.com/golang/protobuf/ptypes/empty"
 	"github.com/prysmaticlabs/prysm/beacon-chain/casper"
 	"github.com/prysmaticlabs/prysm/beacon-chain/params"
@@ -46,6 +45,7 @@ type canonicalFetcher interface {
 type chainService interface {
 	IncomingBlockFeed() *event.Feed
 	CurrentCrystallizedState() *types.CrystallizedState
+	GenesisBlock() (*types.Block, error)
 }
 
 type attestationService interface {
@@ -178,8 +178,12 @@ func (s *Service) CurrentAssignmentsAndGenesisTime(ctx context.Context, req *pb.
 	// This error is safe to ignore as we are initializing a proto timestamp
 	// from a constant value (genesis time is constant in the protocol
 	// and defined in the params.GetConfig().package).
-	// #nosec G104
-	protoGenesis, _ := ptypes.TimestampProto(params.GetConfig().GenesisTime)
+	// Get the genesis timestamp from persistent storage.
+	genesis, err := s.chainService.GenesisBlock()
+	if err != nil {
+		return nil, fmt.Errorf("could not get genesis block: %v", err)
+	}
+
 	cState := s.chainService.CurrentCrystallizedState()
 	var keys []*pb.PublicKey
 	if req.AllValidators {
@@ -198,7 +202,7 @@ func (s *Service) CurrentAssignmentsAndGenesisTime(ctx context.Context, req *pb.
 	}
 
 	return &pb.CurrentAssignmentsResponse{
-		GenesisTimestamp: protoGenesis,
+		GenesisTimestamp: genesis.Proto().GetTimestamp(),
 		Assignments:      assignments,
 	}, nil
 }

beacon-chain/rpc/service_test.go

@@ -50,6 +50,10 @@ func (f *faultyChainService) CanonicalCrystallizedStateFeed() *event.Feed {
 	return nil
 }
 
+func (f *faultyChainService) GenesisBlock() (*types.Block, error) {
+	return nil, errors.New("failed")
+}
+
 type mockChainService struct {
 	blockFeed       *event.Feed
 	stateFeed       *event.Feed
@@ -96,6 +100,10 @@ func (m *mockChainService) CanonicalCrystallizedState() *types.CrystallizedState
 	return types.NewCrystallizedState(data)
 }
 
+func (m *mockChainService) GenesisBlock() (*types.Block, error) {
+	return types.NewGenesisBlock([32]byte{}, [32]byte{}), nil
+}
+
 func newMockChainService() *mockChainService {
 	return &mockChainService{
 		blockFeed:       new(event.Feed),

beacon-chain/types/block.go

@@ -138,9 +138,9 @@ func (b *Block) Timestamp() (time.Time, error) {
 }
 
 // isSlotValid compares the slot to the system clock to determine if the block is valid.
-func (b *Block) isSlotValid() bool {
+func (b *Block) isSlotValid(genesisTimestamp time.Time) bool {
 	slotDuration := time.Duration(b.SlotNumber()*params.GetConfig().SlotDuration) * time.Second
-	validTimeThreshold := params.GetConfig().GenesisTime.Add(slotDuration)
+	validTimeThreshold := genesisTimestamp.Add(slotDuration)
 	return clock.Now().After(validTimeThreshold)
 }
 
@@ -152,7 +152,8 @@ func (b *Block) IsValid(
 	aState *ActiveState,
 	cState *CrystallizedState,
 	parentSlot uint64,
-	enableAttestationValidity bool) bool {
+	enableAttestationValidity bool,
+	genesisTimestamp time.Time) bool {
 	_, err := b.Hash()
 	if err != nil {
 		log.Errorf("Could not hash incoming block: %v", err)
@@ -164,7 +165,7 @@ func (b *Block) IsValid(
 		return false
 	}
 
-	if !b.isSlotValid() {
+	if !b.isSlotValid(genesisTimestamp) {
 		log.Errorf("Slot of block is too high: %d", b.SlotNumber())
 		return false
 	}

beacon-chain/types/block_test.go

@@ -107,10 +107,11 @@ func TestBlockValidity(t *testing.T) {
 		t.Fatalf("failed attestation validation")
 	}
 
-	if !b.IsValid(chainService, aState, cState, parentSlot, false) {
+	genesisTime := params.GetConfig().GenesisTime
+	if !b.IsValid(chainService, aState, cState, parentSlot, false, genesisTime) {
 		t.Fatalf("failed block validation")
 	}
-	if !b.IsValid(chainService, aState, cState, parentSlot, true) {
+	if !b.IsValid(chainService, aState, cState, parentSlot, true, genesisTime) {
 		t.Fatalf("failed block validation")
 	}
 }