add db functions for last checkpoint

beacon-chain/db/kv/BUILD.bazel

@@ -25,6 +25,7 @@ go_library(
         "state_summary.go",
         "state_summary_cache.go",
         "utils.go",
+        "validated_checkpoint.go",
         "wss.go",
     ],
     importpath = "github.com/prysmaticlabs/prysm/beacon-chain/db/kv",
@@ -91,6 +92,7 @@ go_test(
         "state_summary_test.go",
         "state_test.go",
         "utils_test.go",
+        "validated_checkpoint_test.go",
     ],
     data = glob(["testdata/**"]),
     embed = [":go_default_library"],

beacon-chain/db/kv/kv.go

@@ -175,7 +175,7 @@ func NewKVStore(ctx context.Context, dirPath string, config *Config) (*Store, er
 			powchainBucket,
 			stateSummaryBucket,
 			stateValidatorsBucket,
-			validatedTips,
+			lastValidatedCheckpoint,
 			// Indices buckets.
 			attestationHeadBlockRootBucket,
 			attestationSourceRootIndicesBucket,

beacon-chain/db/kv/schema.go

@@ -19,7 +19,7 @@ var (
 	powchainBucket          = []byte("powchain")
 	stateValidatorsBucket   = []byte("state-validators")
 	feeRecipientBucket      = []byte("fee-recipient")
-	validatedTips           = []byte("validated-synced-tips")
+	lastValidatedCheckpoint = []byte("last-validated-checkpoint")
 
 	// Deprecated: This bucket was migrated in PR 6461. Do not use, except for migrations.
 	slotsHasObjectBucket = []byte("slots-has-objects")

beacon-chain/db/kv/validated_checkpoint.go

@@ -0,0 +1,47 @@
+package kv
+
+import (
+	"context"
+	"encoding/binary"
+
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
+	bolt "go.etcd.io/bbolt"
+	"go.opencensus.io/trace"
+)
+
+func (s *Store) LastValidatedCheckpoint(ctx context.Context) ([32]byte, types.Slot, error) {
+	ctx, span := trace.StartSpan(ctx, "BeaconDB.LastValidatedCheckpoint")
+	defer span.End()
+
+	var lastChkPoint [32]byte
+	var slot types.Slot
+	err := s.db.View(func(tx *bolt.Tx) error {
+		bkt := tx.Bucket(lastValidatedCheckpoint)
+		val := bkt.Get([]byte("lastChkPoint"))
+		if len(val) != 40 {
+			return errors.New("invalid checkpoint point")
+		}
+		lastChkPoint = bytesutil.ToBytes32(val[:32])
+		slot = types.Slot(binary.LittleEndian.Uint64(val[32:]))
+		return nil
+	})
+	return lastChkPoint, slot, err
+}
+
+func (s *Store) saveLastValidatedCheckpoint(ctx context.Context, checkPoint [32]byte, slot types.Slot) error {
+	ctx, span := trace.StartSpan(ctx, "BeaconDB.saveLastValidatedCheckpoint")
+	defer span.End()
+
+	updateErr := s.db.Update(func(tx *bolt.Tx) error {
+		value := make([]byte, 40)
+		copy(value[:32], checkPoint[:])
+		binary.LittleEndian.PutUint64(value[32:], uint64(slot))
+		bkt := tx.Bucket(lastValidatedCheckpoint)
+		err := bkt.Put([]byte("lastChkPoint"), value)
+		return err
+	})
+
+	return updateErr
+}

beacon-chain/db/kv/validated_checkpoint_test.go

@@ -0,0 +1,39 @@
+package kv
+
+import (
+	"bytes"
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/testing/require"
+)
+
+func TestValidateCheckpoint(t *testing.T) {
+	ctx := context.Background()
+	db := setupDB(t)
+
+	checkpointA := [32]byte{'A'}
+	slotA := types.Slot(1)
+
+	checkpointB := [32]byte{'B'}
+	slotB := types.Slot(2)
+
+	// add first checkpoint
+	require.NoError(t, db.saveLastValidatedCheckpoint(ctx, checkpointA, slotA))
+
+	rcvdRoot, rcvdSlot, err := db.LastValidatedCheckpoint(ctx)
+	require.NoError(t, err)
+
+	require.Equal(t, 0, bytes.Compare(checkpointA[:], rcvdRoot[:]))
+	require.Equal(t, true, uint64(slotA) == uint64(rcvdSlot))
+
+	// update the checkpoint and slot
+	require.NoError(t, db.saveLastValidatedCheckpoint(ctx, checkpointB, slotB))
+
+	rcvdRoot, rcvdSlot, err = db.LastValidatedCheckpoint(ctx)
+	require.NoError(t, err)
+
+	require.Equal(t, 0, bytes.Compare(checkpointB[:], rcvdRoot[:]))
+	require.Equal(t, true, uint64(slotB) == uint64(rcvdSlot))
+}