Refactor blockchain database for modularity

blockchain/blockchain.go

@@ -3,13 +3,11 @@ package blockchain
 import (
 	"bytes"
 	"context"
-	"encoding/binary"
-	"encoding/hex"
-	"errors"
 	"fmt"
-	"os"
 	"sync"
 
+	"github.com/Secured-Finance/dione/blockchain/database"
+
 	drand2 "github.com/Secured-Finance/dione/beacon/drand"
 
 	"github.com/Secured-Finance/dione/beacon"
@@ -26,105 +24,30 @@ import (
 
 	types2 "github.com/Secured-Finance/dione/blockchain/types"
 	"github.com/fxamacker/cbor/v2"
-
-	"github.com/ledgerwatch/lmdb-go/lmdb"
-)
-
-const (
-	DefaultBlockDataPrefix   = "blockdata_"
-	DefaultBlockHeaderPrefix = "header_"
-	DefaultMetadataIndexName = "metadata"
-	LatestBlockHeightKey     = "latest_block_height"
-)
-
-var (
-	ErrBlockNotFound   = errors.New("block isn't found")
-	ErrLatestHeightNil = errors.New("latest block height is nil")
 )
 
 type BlockChain struct {
-	// db-related
-	dbEnv         *lmdb.Env
-	db            lmdb.DBI
-	metadataIndex *utils.Index
-	heightIndex   *utils.Index
-
+	db          database.Database
 	bus         EventBus.Bus
 	miner       *Miner
 	drandBeacon *drand2.DrandBeacon
 }
 
-func NewBlockChain(path string, bus EventBus.Bus, miner *Miner, db *drand2.DrandBeacon) (*BlockChain, error) {
+func NewBlockChain(db database.Database, bus EventBus.Bus, miner *Miner, drand *drand2.DrandBeacon) (*BlockChain, error) {
 	chain := &BlockChain{
+		db:          db,
 		bus:         bus,
 		miner:       miner,
-		drandBeacon: db,
+		drandBeacon: drand,
 	}
 
-	// configure lmdb env
-	env, err := lmdb.NewEnv()
-	if err != nil {
-		return nil, err
-	}
-
-	err = env.SetMaxDBs(1)
-	if err != nil {
-		return nil, err
-	}
-	err = env.SetMapSize(100 * 1024 * 1024 * 1024) // 100 GB
-	if err != nil {
-		return nil, err
-	}
-
-	err = os.MkdirAll(path, 0755)
-	if err != nil {
-		return nil, err
-	}
-
-	err = env.Open(path, 0, 0755)
-	if err != nil {
-		return nil, err
-	}
-
-	chain.dbEnv = env
-
-	var dbi lmdb.DBI
-	err = env.Update(func(txn *lmdb.Txn) error {
-		dbi, err = txn.OpenDBI("blocks", lmdb.Create)
-		return err
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	chain.db = dbi
-
-	// create index instances
-	metadataIndex := utils.NewIndex(DefaultMetadataIndexName, env, dbi)
-	heightIndex := utils.NewIndex("height", env, dbi)
-	chain.metadataIndex = metadataIndex
-	chain.heightIndex = heightIndex
+	logrus.Info("Blockchain has been successfully initialized!")
 
 	return chain, nil
 }
 
-func (bc *BlockChain) setLatestBlockHeight(height uint64) error {
-	err := bc.metadataIndex.PutUint64([]byte(LatestBlockHeightKey), height)
-	if err != nil {
-		return err
-	}
-	return nil
-}
-
 func (bc *BlockChain) GetLatestBlockHeight() (uint64, error) {
-	height, err := bc.metadataIndex.GetUint64([]byte(LatestBlockHeightKey))
-	if err != nil {
-		if err == utils.ErrIndexKeyNotFound {
-			return 0, ErrLatestHeightNil
-		}
-		return 0, err
-	}
-	return height, nil
+	return bc.db.GetLatestBlockHeight()
 }
 
 func (bc *BlockChain) StoreBlock(block *types2.Block) error {
@@ -142,43 +65,18 @@ func (bc *BlockChain) StoreBlock(block *types2.Block) error {
 		}
 	}
 
-	err := bc.dbEnv.Update(func(txn *lmdb.Txn) error {
-		data, err := cbor.Marshal(block.Data)
-		if err != nil {
-			return err
-		}
-		headerData, err := cbor.Marshal(block.Header)
-		if err != nil {
-			return err
-		}
-		blockHash := hex.EncodeToString(block.Header.Hash)
-		err = txn.Put(bc.db, []byte(DefaultBlockDataPrefix+blockHash), data, 0)
-		if err != nil {
-			return err
-		}
-		err = txn.Put(bc.db, []byte(DefaultBlockHeaderPrefix+blockHash), headerData, 0) // store header separately for easy fetching
-		return err
-	})
-	if err != nil {
-		return err
-	}
-
-	// update index "height -> block hash"
-	heightBytes := make([]byte, 8)
-	binary.LittleEndian.PutUint64(heightBytes, block.Header.Height)
-	err = bc.heightIndex.PutBytes(heightBytes, block.Header.Hash)
-	if err != nil {
+	if err := bc.db.StoreBlock(block); err != nil {
 		return err
 	}
 
 	// update latest block height
 	height, err := bc.GetLatestBlockHeight()
-	if err != nil && err != ErrLatestHeightNil {
+	if err != nil && err != database.ErrLatestHeightNil {
 		return err
 	}
 
-	if err == ErrLatestHeightNil || block.Header.Height > height {
-		if err = bc.setLatestBlockHeight(block.Header.Height); err != nil {
+	if err == database.ErrLatestHeightNil || block.Header.Height > height {
+		if err = bc.db.SetLatestBlockHeight(block.Header.Height); err != nil {
 			return err
 		}
 		bc.bus.Publish("blockchain:latestBlockHeightUpdated", block)
@@ -188,114 +86,27 @@ func (bc *BlockChain) StoreBlock(block *types2.Block) error {
 }
 
 func (bc *BlockChain) HasBlock(blockHash []byte) (bool, error) {
-	var blockExists bool
-	err := bc.dbEnv.View(func(txn *lmdb.Txn) error {
-		h := hex.EncodeToString(blockHash)
-		_, err := txn.Get(bc.db, []byte(DefaultBlockHeaderPrefix+h)) // try to fetch block header
-		if err != nil {
-			if lmdb.IsNotFound(err) {
-				blockExists = false
-				return nil
-			}
-			return err
-		}
-		blockExists = true
-		return nil
-	})
-	if err != nil {
-		return false, err
-	}
-	return blockExists, nil
+	return bc.db.HasBlock(blockHash)
 }
 
 func (bc *BlockChain) FetchBlockData(blockHash []byte) ([]*types2.Transaction, error) {
-	var data []*types2.Transaction
-	err := bc.dbEnv.View(func(txn *lmdb.Txn) error {
-		h := hex.EncodeToString(blockHash)
-		blockData, err := txn.Get(bc.db, []byte(DefaultBlockDataPrefix+h))
-		if err != nil {
-			if lmdb.IsNotFound(err) {
-				return ErrBlockNotFound
-			}
-			return err
-		}
-		err = cbor.Unmarshal(blockData, &data)
-		return err
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	return data, nil
+	return bc.db.FetchBlockData(blockHash)
 }
 
 func (bc *BlockChain) FetchBlockHeader(blockHash []byte) (*types2.BlockHeader, error) {
-	var blockHeader types2.BlockHeader
-	err := bc.dbEnv.View(func(txn *lmdb.Txn) error {
-		h := hex.EncodeToString(blockHash)
-		data, err := txn.Get(bc.db, []byte(DefaultBlockHeaderPrefix+h))
-		if err != nil {
-			if lmdb.IsNotFound(err) {
-				return ErrBlockNotFound
-			}
-			return err
-		}
-		err = cbor.Unmarshal(data, &blockHeader)
-		return err
-	})
-	if err != nil {
-		return nil, err
-	}
-	return &blockHeader, nil
+	return bc.db.FetchBlockHeader(blockHash)
 }
 
 func (bc *BlockChain) FetchBlock(blockHash []byte) (*types2.Block, error) {
-	var block types2.Block
-	header, err := bc.FetchBlockHeader(blockHash)
-	if err != nil {
-		return nil, err
-	}
-	block.Header = header
-
-	data, err := bc.FetchBlockData(blockHash)
-	if err != nil {
-		return nil, err
-	}
-	block.Data = data
-
-	return &block, nil
+	return bc.db.FetchBlock(blockHash)
 }
 
 func (bc *BlockChain) FetchBlockByHeight(height uint64) (*types2.Block, error) {
-	var heightBytes = make([]byte, 8)
-	binary.LittleEndian.PutUint64(heightBytes, height)
-	blockHash, err := bc.heightIndex.GetBytes(heightBytes)
-	if err != nil {
-		if err == utils.ErrIndexKeyNotFound {
-			return nil, ErrBlockNotFound
-		}
-	}
-	block, err := bc.FetchBlock(blockHash)
-	if err != nil {
-		return nil, err
-	}
-	return block, nil
+	return bc.db.FetchBlockByHeight(height)
 }
 
 func (bc *BlockChain) FetchBlockHeaderByHeight(height uint64) (*types2.BlockHeader, error) {
-	var heightBytes = make([]byte, 8)
-	binary.LittleEndian.PutUint64(heightBytes, height)
-	blockHash, err := bc.heightIndex.GetBytes(heightBytes)
-	if err != nil {
-		if err == utils.ErrIndexKeyNotFound {
-			return nil, ErrBlockNotFound
-		}
-	}
-	blockHeader, err := bc.FetchBlockHeader(blockHash)
-	if err != nil {
-		return nil, err
-	}
-	return blockHeader, nil
+	return bc.db.FetchBlockHeaderByHeight(height)
 }
 
 func (bc *BlockChain) ValidateBlock(block *types2.Block) error {

blockchain/database/database.go

@@ -0,0 +1,25 @@
+package database
+
+import (
+	"errors"
+
+	"github.com/Secured-Finance/dione/blockchain/types"
+	types2 "github.com/Secured-Finance/dione/blockchain/types"
+)
+
+var (
+	ErrBlockNotFound   = errors.New("block isn't found")
+	ErrLatestHeightNil = errors.New("latest block height is nil")
+)
+
+type Database interface {
+	StoreBlock(block *types.Block) error
+	HasBlock(blockhash []byte) (bool, error)
+	FetchBlockData(blockHash []byte) ([]*types2.Transaction, error)
+	FetchBlockHeader(blockHash []byte) (*types2.BlockHeader, error)
+	FetchBlock(blockHash []byte) (*types2.Block, error)
+	FetchBlockByHeight(height uint64) (*types2.Block, error)
+	FetchBlockHeaderByHeight(height uint64) (*types2.BlockHeader, error)
+	GetLatestBlockHeight() (uint64, error)
+	SetLatestBlockHeight(height uint64) error
+}

blockchain/database/lmdb/database.go

@@ -0,0 +1,239 @@
+package lmdb
+
+import (
+	"encoding/binary"
+	"encoding/hex"
+	"os"
+
+	"github.com/Secured-Finance/dione/blockchain/database"
+	types2 "github.com/Secured-Finance/dione/blockchain/types"
+	"github.com/fxamacker/cbor/v2"
+	"github.com/ledgerwatch/lmdb-go/lmdb"
+)
+
+const (
+	DefaultBlockDataPrefix   = "blockdata_"
+	DefaultBlockHeaderPrefix = "header_"
+	DefaultMetadataIndexName = "metadata"
+	LatestBlockHeightKey     = "latest_block_height"
+)
+
+type Database struct {
+	dbEnv         *lmdb.Env
+	db            lmdb.DBI
+	metadataIndex *Index
+	heightIndex   *Index
+}
+
+func NewDatabase(path string) (*Database, error) {
+	db := &Database{}
+
+	// configure lmdb env
+	env, err := lmdb.NewEnv()
+	if err != nil {
+		return nil, err
+	}
+
+	err = env.SetMaxDBs(1)
+	if err != nil {
+		return nil, err
+	}
+	err = env.SetMapSize(100 * 1024 * 1024 * 1024) // 100 GB
+	if err != nil {
+		return nil, err
+	}
+
+	err = os.MkdirAll(path, 0755)
+	if err != nil {
+		return nil, err
+	}
+
+	err = env.Open(path, 0, 0755)
+	if err != nil {
+		return nil, err
+	}
+
+	db.dbEnv = env
+
+	var dbi lmdb.DBI
+	err = env.Update(func(txn *lmdb.Txn) error {
+		dbi, err = txn.OpenDBI("blocks", lmdb.Create)
+		return err
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	db.db = dbi
+
+	// create index instances
+	metadataIndex := NewIndex(DefaultMetadataIndexName, env, dbi)
+	heightIndex := NewIndex("height", env, dbi)
+	db.metadataIndex = metadataIndex
+	db.heightIndex = heightIndex
+
+	return db, nil
+}
+
+func (d *Database) StoreBlock(block *types2.Block) error {
+	err := d.dbEnv.Update(func(txn *lmdb.Txn) error {
+		data, err := cbor.Marshal(block.Data)
+		if err != nil {
+			return err
+		}
+		headerData, err := cbor.Marshal(block.Header)
+		if err != nil {
+			return err
+		}
+		blockHash := hex.EncodeToString(block.Header.Hash)
+		err = txn.Put(d.db, []byte(DefaultBlockDataPrefix+blockHash), data, 0)
+		if err != nil {
+			return err
+		}
+		err = txn.Put(d.db, []byte(DefaultBlockHeaderPrefix+blockHash), headerData, 0) // store header separately for easy fetching
+		return err
+	})
+	if err != nil {
+		return err
+	}
+
+	// update index "height -> block hash"
+	heightBytes := make([]byte, 8)
+	binary.LittleEndian.PutUint64(heightBytes, block.Header.Height)
+	err = d.heightIndex.PutBytes(heightBytes, block.Header.Hash)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (d *Database) HasBlock(blockHash []byte) (bool, error) {
+	var blockExists bool
+	err := d.dbEnv.View(func(txn *lmdb.Txn) error {
+		h := hex.EncodeToString(blockHash)
+		_, err := txn.Get(d.db, []byte(DefaultBlockHeaderPrefix+h)) // try to fetch block header
+		if err != nil {
+			if lmdb.IsNotFound(err) {
+				blockExists = false
+				return nil
+			}
+			return err
+		}
+		blockExists = true
+		return nil
+	})
+	if err != nil {
+		return false, err
+	}
+	return blockExists, nil
+}
+
+func (d *Database) FetchBlockData(blockHash []byte) ([]*types2.Transaction, error) {
+	var data []*types2.Transaction
+	err := d.dbEnv.View(func(txn *lmdb.Txn) error {
+		h := hex.EncodeToString(blockHash)
+		blockData, err := txn.Get(d.db, []byte(DefaultBlockDataPrefix+h))
+		if err != nil {
+			if lmdb.IsNotFound(err) {
+				return database.ErrBlockNotFound
+			}
+			return err
+		}
+		err = cbor.Unmarshal(blockData, &data)
+		return err
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return data, nil
+}
+
+func (d *Database) FetchBlockHeader(blockHash []byte) (*types2.BlockHeader, error) {
+	var blockHeader types2.BlockHeader
+	err := d.dbEnv.View(func(txn *lmdb.Txn) error {
+		h := hex.EncodeToString(blockHash)
+		data, err := txn.Get(d.db, []byte(DefaultBlockHeaderPrefix+h))
+		if err != nil {
+			if lmdb.IsNotFound(err) {
+				return database.ErrBlockNotFound
+			}
+			return err
+		}
+		err = cbor.Unmarshal(data, &blockHeader)
+		return err
+	})
+	if err != nil {
+		return nil, err
+	}
+	return &blockHeader, nil
+}
+
+func (d *Database) FetchBlock(blockHash []byte) (*types2.Block, error) {
+	var block types2.Block
+	header, err := d.FetchBlockHeader(blockHash)
+	if err != nil {
+		return nil, err
+	}
+	block.Header = header
+
+	data, err := d.FetchBlockData(blockHash)
+	if err != nil {
+		return nil, err
+	}
+	block.Data = data
+
+	return &block, nil
+}
+
+func (d *Database) FetchBlockByHeight(height uint64) (*types2.Block, error) {
+	var heightBytes = make([]byte, 8)
+	binary.LittleEndian.PutUint64(heightBytes, height)
+	blockHash, err := d.heightIndex.GetBytes(heightBytes)
+	if err != nil {
+		if err == ErrIndexKeyNotFound {
+			return nil, database.ErrBlockNotFound
+		}
+	}
+	block, err := d.FetchBlock(blockHash)
+	if err != nil {
+		return nil, err
+	}
+	return block, nil
+}
+
+func (d *Database) FetchBlockHeaderByHeight(height uint64) (*types2.BlockHeader, error) {
+	var heightBytes = make([]byte, 8)
+	binary.LittleEndian.PutUint64(heightBytes, height)
+	blockHash, err := d.heightIndex.GetBytes(heightBytes)
+	if err != nil {
+		if err == ErrIndexKeyNotFound {
+			return nil, database.ErrBlockNotFound
+		}
+	}
+	blockHeader, err := d.FetchBlockHeader(blockHash)
+	if err != nil {
+		return nil, err
+	}
+	return blockHeader, nil
+}
+
+func (d *Database) GetLatestBlockHeight() (uint64, error) {
+	height, err := d.metadataIndex.GetUint64([]byte(LatestBlockHeightKey))
+	if err != nil {
+		if err == ErrIndexKeyNotFound {
+			return 0, database.ErrLatestHeightNil
+		}
+		return 0, err
+	}
+	return height, nil
+}
+
+func (d *Database) SetLatestBlockHeight(height uint64) error {
+	err := d.metadataIndex.PutUint64([]byte(LatestBlockHeightKey), height)
+	if err != nil {
+		return err
+	}
+	return nil
+}

blockchain/database/lmdb/index.go

@@ -1,4 +1,4 @@
-package utils
+package lmdb
 
 import (
 	"encoding/binary"

blockchain/database/memory/database.go

@@ -0,0 +1,90 @@
+package memory
+
+import (
+	"encoding/hex"
+	"fmt"
+
+	"github.com/Secured-Finance/dione/blockchain/database"
+
+	types2 "github.com/Secured-Finance/dione/blockchain/types"
+	"github.com/patrickmn/go-cache"
+)
+
+const (
+	LatestBlockHeightKey = "latest_block_height"
+)
+
+type Database struct {
+	db *cache.Cache
+}
+
+func NewDatabase() *Database {
+	return &Database{
+		db: cache.New(cache.NoExpiration, 0),
+	}
+}
+
+func (d *Database) StoreBlock(block *types2.Block) error {
+	h := hex.EncodeToString(block.Header.Hash)
+	d.db.SetDefault(h, block)
+	d.db.SetDefault(fmt.Sprintf("height/%d", block.Header.Height), block)
+	return nil
+}
+
+func (d *Database) HasBlock(blockHash []byte) (bool, error) {
+	_, ok := d.db.Get(hex.EncodeToString(blockHash))
+	return ok, nil
+}
+
+func (d *Database) FetchBlockData(blockHash []byte) ([]*types2.Transaction, error) {
+	b, err := d.FetchBlock(blockHash)
+	if err != nil {
+		return nil, err
+	}
+	return b.Data, nil
+}
+
+func (d *Database) FetchBlockHeader(blockHash []byte) (*types2.BlockHeader, error) {
+	b, err := d.FetchBlock(blockHash)
+	if err != nil {
+		return nil, err
+	}
+	return b.Header, nil
+}
+
+func (d *Database) FetchBlock(blockHash []byte) (*types2.Block, error) {
+	b, ok := d.db.Get(hex.EncodeToString(blockHash))
+	if !ok {
+		return nil, database.ErrBlockNotFound
+	}
+	return b.(*types2.Block), nil
+}
+
+func (d *Database) FetchBlockByHeight(height uint64) (*types2.Block, error) {
+	b, ok := d.db.Get(fmt.Sprintf("height/%d", height))
+	if !ok {
+		return nil, database.ErrBlockNotFound
+	}
+	return b.(*types2.Block), nil
+}
+
+func (d *Database) FetchBlockHeaderByHeight(height uint64) (*types2.BlockHeader, error) {
+	b, ok := d.db.Get(fmt.Sprintf("height/%d", height))
+	if !ok {
+		return nil, database.ErrBlockNotFound
+	}
+	return b.(*types2.Block).Header, nil
+}
+
+func (d *Database) GetLatestBlockHeight() (uint64, error) {
+	height, ok := d.db.Get(LatestBlockHeightKey)
+	if !ok {
+		return 0, database.ErrLatestHeightNil
+	}
+	return height.(uint64), nil
+}
+
+func (d *Database) SetLatestBlockHeight(height uint64) error {
+	d.db.SetDefault(LatestBlockHeightKey, height)
+	return nil
+}

config/config.go

@@ -7,8 +7,11 @@ import (
 )
 
 const (
-	CacheTypeInMemory = "in-memory"
+	CacheTypeInMemory = "memory"
 	CacheTypeRedis    = "redis"
+
+	BlockchainDatabaseInMemory = "memory"
+	BlockChainDatabaseLMDB     = "lmdb"
 )
 
 type Config struct {
@@ -60,7 +63,10 @@ type RedisConfig struct {
 }
 
 type BlockchainConfig struct {
-	DatabasePath string `mapstructure:"database_path"`
+	DatabaseType string `mapstructure:"database_type"`
+	LMDB         struct {
+		DatabasePath string `mapstructure:"database_path"`
+	} `mapstructure:"lmdb"`
 }
 
 // NewConfig creates a new config based on default values or provided .env file

node/node.go

@@ -202,8 +202,9 @@ func Start() {
 			providePeerDiscovery,
 			drand2.NewDrandBeacon,
 			pool.NewMempool,
+			provideBlockchainDatabase,
 			blockchain.NewMiner,
-			provideBlockChain,
+			blockchain.NewBlockChain,
 			sync.NewSyncManager,
 			provideNetworkRPCHost,
 			NewNetworkService,

node/node_dep_providers.go

@@ -11,6 +11,12 @@ import (
 	"path/filepath"
 	"runtime"
 
+	"github.com/Secured-Finance/dione/blockchain/database/memory"
+
+	"github.com/Secured-Finance/dione/blockchain/database/lmdb"
+
+	"github.com/Secured-Finance/dione/blockchain/database"
+
 	"github.com/Secured-Finance/dione/cache/inmemory"
 
 	"github.com/Secured-Finance/dione/cache/redis"
@@ -24,12 +30,8 @@ import (
 
 	"github.com/sirupsen/logrus"
 
-	"github.com/asaskevich/EventBus"
-
 	"github.com/Secured-Finance/dione/blockchain"
 
-	drand2 "github.com/Secured-Finance/dione/beacon/drand"
-
 	"github.com/libp2p/go-libp2p-core/protocol"
 
 	gorpc "github.com/libp2p/go-libp2p-gorpc"
@@ -64,6 +66,29 @@ func provideCacheManager(cfg *config.Config) cache.CacheManager {
 	return backend
 }
 
+func provideBlockchainDatabase(cfg *config.Config) (database.Database, error) {
+	var db database.Database
+	switch cfg.Blockchain.DatabaseType {
+	case config.BlockchainDatabaseInMemory:
+		db = memory.NewDatabase()
+	case config.BlockChainDatabaseLMDB:
+		{
+			if cfg.Blockchain.LMDB.DatabasePath == "" {
+				return nil, fmt.Errorf("database path for lmdb database is empty")
+			}
+			l, err := lmdb.NewDatabase(cfg.Blockchain.LMDB.DatabasePath)
+			if err != nil {
+				return nil, err
+			}
+			db = l
+		}
+	default:
+		db = memory.NewDatabase()
+	}
+
+	return db, nil
+}
+
 // FIXME: do we really need this?
 //func provideWallet(peerID peer.ID, privKey []byte) (*wallet.LocalWallet, error) {
 //	// TODO make persistent keystore
@@ -163,16 +188,6 @@ func providePeerDiscovery(baddrs []multiaddr.Multiaddr, h host.Host) discovery.D
 	return pexDiscovery
 }
 
-func provideBlockChain(config *config.Config, bus EventBus.Bus, miner *blockchain.Miner, db *drand2.DrandBeacon) *blockchain.BlockChain {
-	bc, err := blockchain.NewBlockChain(config.Blockchain.DatabasePath, bus, miner, db)
-	if err != nil {
-		logrus.Fatalf("Failed to initialize blockchain storage: %s", err.Error())
-	}
-	logrus.Info("Blockchain storage has been successfully initialized!")
-
-	return bc
-}
-
 func provideDirectRPCClient(h host.Host) *gorpc.Client {
 	return gorpc.NewClient(h, DioneProtocolID)
 }
@@ -303,7 +318,7 @@ func configureMiner(m *blockchain.Miner, b *blockchain.BlockChain) {
 
 func initializeBlockchain(bc *blockchain.BlockChain) {
 	_, err := bc.GetLatestBlockHeight()
-	if err == blockchain.ErrLatestHeightNil {
+	if err == database.ErrLatestHeightNil {
 		gBlock := types2.GenesisBlock()
 		err = bc.StoreBlock(gBlock) // commit genesis block
 		if err != nil {