// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see .
// Package eth implements the Ethereum protocol.
package eth
import (
"errors"
"fmt"
"math/big"
"os"
"reflect"
"runtime"
"sync"
"sync/atomic"
"github.com/ledgerwatch/turbo-geth/accounts"
"github.com/ledgerwatch/turbo-geth/accounts/abi/bind"
"github.com/ledgerwatch/turbo-geth/common"
"github.com/ledgerwatch/turbo-geth/common/hexutil"
"github.com/ledgerwatch/turbo-geth/consensus"
"github.com/ledgerwatch/turbo-geth/consensus/clique"
"github.com/ledgerwatch/turbo-geth/consensus/ethash"
"github.com/ledgerwatch/turbo-geth/core"
"github.com/ledgerwatch/turbo-geth/core/bloombits"
"github.com/ledgerwatch/turbo-geth/core/rawdb"
"github.com/ledgerwatch/turbo-geth/core/types"
"github.com/ledgerwatch/turbo-geth/core/vm"
"github.com/ledgerwatch/turbo-geth/eth/downloader"
"github.com/ledgerwatch/turbo-geth/eth/filters"
"github.com/ledgerwatch/turbo-geth/eth/gasprice"
"github.com/ledgerwatch/turbo-geth/ethdb"
"github.com/ledgerwatch/turbo-geth/ethdb/remote/remotedbserver"
"github.com/ledgerwatch/turbo-geth/event"
"github.com/ledgerwatch/turbo-geth/internal/ethapi"
"github.com/ledgerwatch/turbo-geth/log"
"github.com/ledgerwatch/turbo-geth/miner"
"github.com/ledgerwatch/turbo-geth/node"
"github.com/ledgerwatch/turbo-geth/p2p"
"github.com/ledgerwatch/turbo-geth/p2p/enode"
"github.com/ledgerwatch/turbo-geth/p2p/enr"
"github.com/ledgerwatch/turbo-geth/params"
"github.com/ledgerwatch/turbo-geth/rlp"
"github.com/ledgerwatch/turbo-geth/rpc"
)
type LesServer interface {
Start(srvr *p2p.Server)
Stop()
APIs() []rpc.API
Protocols() []p2p.Protocol
SetBloomBitsIndexer(bbIndexer *core.ChainIndexer)
SetContractBackend(bind.ContractBackend)
}
// Ethereum implements the Ethereum full node service.
type Ethereum struct {
config *Config
// Handlers
txPool *core.TxPool
blockchain *core.BlockChain
protocolManager *ProtocolManager
lesServer LesServer
dialCandidates enode.Iterator
// DB interfaces
chainDb *ethdb.ObjectDatabase // Block chain database
chainKV ethdb.KV // Same as chainDb, but different interface
eventMux *event.TypeMux
engine consensus.Engine
accountManager *accounts.Manager
bloomRequests chan chan *bloombits.Retrieval // Channel receiving bloom data retrieval requests
bloomIndexer *core.ChainIndexer // Bloom indexer operating during block imports
closeBloomHandler chan struct{}
APIBackend *EthAPIBackend
miner *miner.Miner
gasPrice *big.Int
etherbase common.Address
networkID uint64
netRPCService *ethapi.PublicNetAPI
lock sync.RWMutex // Protects the variadic fields (e.g. gas price and etherbase)
txPoolStarted bool
}
func (s *Ethereum) AddLesServer(ls LesServer) {
s.lesServer = ls
ls.SetBloomBitsIndexer(s.bloomIndexer)
}
// SetClient sets a rpc client which connecting to our local node.
func (s *Ethereum) SetContractBackend(backend bind.ContractBackend) {
// Pass the rpc client to les server if it is enabled.
if s.lesServer != nil {
s.lesServer.SetContractBackend(backend)
}
}
// New creates a new Ethereum object (including the
// initialisation of the common Ethereum object)
func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
// Ensure configuration values are compatible and sane
if config.SyncMode == downloader.LightSync {
return nil, errors.New("can't run eth.Ethereum in light sync mode, use les.LightEthereum")
}
if !config.SyncMode.IsValid() {
return nil, fmt.Errorf("invalid sync mode %d", config.SyncMode)
}
if config.Miner.GasPrice == nil || config.Miner.GasPrice.Cmp(common.Big0) <= 0 {
log.Warn("Sanitizing invalid miner gas price", "provided", config.Miner.GasPrice, "updated", DefaultConfig.Miner.GasPrice)
config.Miner.GasPrice = new(big.Int).Set(DefaultConfig.Miner.GasPrice)
}
if !config.Pruning && config.TrieDirtyCache > 0 {
if config.SnapshotCache > 0 {
config.TrieCleanCache += config.TrieDirtyCache * 3 / 5
config.SnapshotCache += config.TrieDirtyCache * 2 / 5
} else {
config.TrieCleanCache += config.TrieDirtyCache
}
config.TrieDirtyCache = 0
}
log.Info("Allocated trie memory caches", "clean", common.StorageSize(config.TrieCleanCache)*1024*1024, "dirty", common.StorageSize(config.TrieDirtyCache)*1024*1024)
// Assemble the Ethereum object
var chainDb *ethdb.ObjectDatabase
var err error
if config.EnableDebugProtocol {
if err = os.RemoveAll("simulator"); err != nil {
return nil, fmt.Errorf("removing simulator db: %w", err)
}
chainDb = ethdb.MustOpen("simulator")
} else {
if chainDb, err = ctx.OpenDatabaseWithFreezer("chaindata", config.DatabaseFreezer); err != nil {
return nil, err
}
}
if ctx.Config.PrivateApiAddr != "" {
//remotedbserver.StartDeprecated(chainDb.KV(), ctx.Config.PrivateApiAddr)
remotedbserver.StartGrpc(chainDb.KV(), ctx.Config.PrivateApiAddr)
}
chainConfig, genesisHash, _, genesisErr := core.SetupGenesisBlock(chainDb, config.Genesis, config.StorageMode.History, false /* overwrite */)
if _, ok := genesisErr.(*params.ConfigCompatError); genesisErr != nil && !ok {
return nil, genesisErr
}
log.Info("Initialised chain configuration", "config", chainConfig)
eth := &Ethereum{
config: config,
chainDb: chainDb,
chainKV: chainDb.KV(),
eventMux: ctx.EventMux,
accountManager: ctx.AccountManager,
engine: CreateConsensusEngine(ctx, chainConfig, &config.Ethash, config.Miner.Notify, config.Miner.Noverify, chainDb),
closeBloomHandler: make(chan struct{}),
networkID: config.NetworkID,
gasPrice: config.Miner.GasPrice,
etherbase: config.Miner.Etherbase,
bloomRequests: make(chan chan *bloombits.Retrieval),
bloomIndexer: NewBloomIndexer(chainDb, params.BloomBitsBlocks, params.BloomConfirms),
}
log.Info("Initialising Ethereum protocol", "versions", ProtocolVersions, "network", config.NetworkID)
bcVersion := rawdb.ReadDatabaseVersion(chainDb)
var dbVer = ""
if bcVersion != nil {
dbVer = fmt.Sprintf("%d", *bcVersion)
}
if !config.SkipBcVersionCheck {
if bcVersion != nil && *bcVersion > core.BlockChainVersion {
return nil, fmt.Errorf("database version is v%d, Geth %s only supports v%d", *bcVersion, params.VersionWithMeta, core.BlockChainVersion)
} else if bcVersion == nil || *bcVersion < core.BlockChainVersion {
log.Warn("Upgrade blockchain database version", "from", dbVer, "to", core.BlockChainVersion)
rawdb.WriteDatabaseVersion(chainDb, core.BlockChainVersion)
}
}
err = ethdb.SetStorageModeIfNotExist(chainDb, config.StorageMode)
if err != nil {
return nil, err
}
sm, err := ethdb.GetStorageModeFromDB(chainDb)
if err != nil {
return nil, err
}
if !reflect.DeepEqual(sm, config.StorageMode) {
return nil, errors.New("mode is " + config.StorageMode.ToString() + " original mode is " + sm.ToString())
}
vmConfig, cacheConfig := BlockchainRuntimeConfig(config)
txCacher := core.NewTxSenderCacher(runtime.NumCPU())
eth.blockchain, err = core.NewBlockChain(chainDb, cacheConfig, chainConfig, eth.engine, vmConfig, eth.shouldPreserve, txCacher)
if err != nil {
return nil, err
}
if config.SyncMode != downloader.StagedSync {
_, err = eth.blockchain.GetTrieDbState()
if err != nil {
return nil, err
}
}
eth.blockchain.EnableReceipts(config.StorageMode.Receipts)
eth.blockchain.EnableTxLookupIndex(config.StorageMode.TxIndex)
// Rewind the chain in case of an incompatible config upgrade.
if compat, ok := genesisErr.(*params.ConfigCompatError); ok {
log.Warn("Rewinding chain to upgrade configuration", "err", compat)
eth.blockchain.SetHead(compat.RewindTo)
rawdb.WriteChainConfig(chainDb, genesisHash, chainConfig)
}
if config.SyncMode != downloader.StagedSync {
eth.bloomIndexer.Start(eth.blockchain)
}
if config.TxPool.Journal != "" {
config.TxPool.Journal = ctx.ResolvePath(config.TxPool.Journal)
}
eth.txPool = core.NewTxPool(config.TxPool, chainConfig, chainDb, txCacher)
checkpoint := config.Checkpoint
if checkpoint == nil {
//checkpoint = params.TrustedCheckpoints[genesisHash]
}
if eth.protocolManager, err = NewProtocolManager(chainConfig, checkpoint, config.SyncMode, config.NetworkID, eth.eventMux, eth.txPool, eth.engine, eth.blockchain, chainDb, config.Whitelist); err != nil {
return nil, err
}
eth.protocolManager.SetDataDir(ctx.Config.DataDir)
if config.SyncMode != downloader.StagedSync {
if err = eth.StartTxPool(); err != nil {
return nil, err
}
}
if config.SyncMode != downloader.StagedSync {
eth.miner = miner.New(eth, &config.Miner, chainConfig, eth.EventMux(), eth.engine, eth.isLocalBlock)
_ = eth.miner.SetExtra(makeExtraData(config.Miner.ExtraData))
}
if config.SyncMode != downloader.StagedSync {
eth.APIBackend = &EthAPIBackend{ctx.ExtRPCEnabled(), eth, nil}
gpoParams := config.GPO
if gpoParams.Default == nil {
gpoParams.Default = config.Miner.GasPrice
}
eth.APIBackend.gpo = gasprice.NewOracle(eth.APIBackend, gpoParams)
}
eth.dialCandidates, err = eth.setupDiscovery(&ctx.Config.P2P)
if err != nil {
return nil, err
}
return eth, nil
}
func BlockchainRuntimeConfig(config *Config) (vm.Config, *core.CacheConfig) {
var (
vmConfig = vm.Config{
EnablePreimageRecording: config.EnablePreimageRecording,
EWASMInterpreter: config.EWASMInterpreter,
EVMInterpreter: config.EVMInterpreter,
}
cacheConfig = &core.CacheConfig{
Pruning: config.Pruning,
BlocksBeforePruning: config.BlocksBeforePruning,
BlocksToPrune: config.BlocksToPrune,
PruneTimeout: config.PruningTimeout,
TrieCleanLimit: config.TrieCleanCache,
TrieCleanNoPrefetch: config.NoPrefetch,
TrieDirtyLimit: config.TrieDirtyCache,
TrieTimeLimit: config.TrieTimeout,
DownloadOnly: config.DownloadOnly,
NoHistory: !config.StorageMode.History,
ArchiveSyncInterval: uint64(config.ArchiveSyncInterval),
}
)
return vmConfig, cacheConfig
}
func makeExtraData(extra []byte) []byte {
if len(extra) == 0 {
// create default extradata
extra, _ = rlp.EncodeToBytes([]interface{}{
uint(params.VersionMajor<<16 | params.VersionMinor<<8 | params.VersionMicro),
"turbo-geth",
runtime.Version(),
runtime.GOOS,
})
}
if uint64(len(extra)) > params.MaximumExtraDataSize {
log.Warn("Miner extra data exceed limit", "extra", hexutil.Bytes(extra), "limit", params.MaximumExtraDataSize)
extra = nil
}
return extra
}
// CreateConsensusEngine creates the required type of consensus engine instance for an Ethereum service
func CreateConsensusEngine(ctx *node.ServiceContext, chainConfig *params.ChainConfig, config *ethash.Config, notify []string, noverify bool, db ethdb.Database) consensus.Engine {
// If proof-of-authority is requested, set it up
if chainConfig.Clique != nil {
return clique.New(chainConfig.Clique, db)
}
// Otherwise assume proof-of-work
switch config.PowMode {
case ethash.ModeFake:
log.Warn("Ethash used in fake mode")
return ethash.NewFaker()
case ethash.ModeTest:
log.Warn("Ethash used in test mode")
return ethash.NewTester(nil, noverify)
case ethash.ModeShared:
log.Warn("Ethash used in shared mode")
return ethash.NewShared()
default:
engine := ethash.New(ethash.Config{
CacheDir: ctx.ResolvePath(config.CacheDir),
CachesInMem: config.CachesInMem,
CachesOnDisk: config.CachesOnDisk,
CachesLockMmap: config.CachesLockMmap,
DatasetDir: config.DatasetDir,
DatasetsInMem: config.DatasetsInMem,
DatasetsOnDisk: config.DatasetsOnDisk,
DatasetsLockMmap: config.DatasetsLockMmap,
}, notify, noverify)
engine.SetThreads(-1) // Disable CPU mining
return engine
}
}
// APIs return the collection of RPC services the ethereum package offers.
// NOTE, some of these services probably need to be moved to somewhere else.
func (s *Ethereum) APIs() []rpc.API {
if s.APIBackend == nil {
return []rpc.API{}
}
apis := ethapi.GetAPIs(s.APIBackend)
// Append any APIs exposed explicitly by the les server
if s.lesServer != nil {
apis = append(apis, s.lesServer.APIs()...)
}
// Append any APIs exposed explicitly by the consensus engine
apis = append(apis, s.engine.APIs(s.BlockChain())...)
// Append any APIs exposed explicitly by the les server
if s.lesServer != nil {
apis = append(apis, s.lesServer.APIs()...)
}
// Append all the local APIs and return
return append(apis, []rpc.API{
{
Namespace: "eth",
Version: "1.0",
Service: NewPublicEthereumAPI(s),
Public: true,
}, {
Namespace: "eth",
Version: "1.0",
Service: NewPublicMinerAPI(s),
Public: true,
}, {
Namespace: "eth",
Version: "1.0",
Service: downloader.NewPublicDownloaderAPI(s.protocolManager.downloader, s.eventMux),
Public: true,
}, {
Namespace: "miner",
Version: "1.0",
Service: NewPrivateMinerAPI(s),
Public: false,
}, {
Namespace: "eth",
Version: "1.0",
Service: filters.NewPublicFilterAPI(s.APIBackend, false),
Public: true,
}, {
Namespace: "admin",
Version: "1.0",
Service: NewPrivateAdminAPI(s),
}, {
Namespace: "debug",
Version: "1.0",
Service: NewPublicDebugAPI(s),
Public: true,
}, {
Namespace: "debug",
Version: "1.0",
Service: NewPrivateDebugAPI(s),
}, {
Namespace: "net",
Version: "1.0",
Service: s.netRPCService,
Public: true,
},
}...)
}
func (s *Ethereum) ResetWithGenesisBlock(gb *types.Block) {
s.blockchain.ResetWithGenesisBlock(gb)
}
func (s *Ethereum) Etherbase() (eb common.Address, err error) {
s.lock.RLock()
etherbase := s.etherbase
s.lock.RUnlock()
if etherbase != (common.Address{}) {
return etherbase, nil
}
if wallets := s.AccountManager().Wallets(); len(wallets) > 0 {
if accounts := wallets[0].Accounts(); len(accounts) > 0 {
etherbase := accounts[0].Address
s.lock.Lock()
s.etherbase = etherbase
s.lock.Unlock()
log.Info("Etherbase automatically configured", "address", etherbase)
return etherbase, nil
}
}
return common.Address{}, fmt.Errorf("etherbase must be explicitly specified")
}
// isLocalBlock checks whether the specified block is mined
// by local miner accounts.
//
// We regard two types of accounts as local miner account: etherbase
// and accounts specified via `txpool.locals` flag.
func (s *Ethereum) isLocalBlock(block *types.Block) bool {
author, err := s.engine.Author(block.Header())
if err != nil {
log.Warn("Failed to retrieve block author", "number", block.NumberU64(), "hash", block.Hash(), "err", err)
return false
}
// Check whether the given address is etherbase.
s.lock.RLock()
etherbase := s.etherbase
s.lock.RUnlock()
if author == etherbase {
return true
}
// Check whether the given address is specified by `txpool.local`
// CLI flag.
for _, account := range s.config.TxPool.Locals {
if account == author {
return true
}
}
return false
}
// shouldPreserve checks whether we should preserve the given block
// during the chain reorg depending on whether the author of block
// is a local account.
func (s *Ethereum) shouldPreserve(block *types.Block) bool {
// The reason we need to disable the self-reorg preserving for clique
// is it can be probable to introduce a deadlock.
//
// e.g. If there are 7 available signers
//
// r1 A
// r2 B
// r3 C
// r4 D
// r5 A [X] F G
// r6 [X]
//
// In the round5, the inturn signer E is offline, so the worst case
// is A, F and G sign the block of round5 and reject the block of opponents
// and in the round6, the last available signer B is offline, the whole
// network is stuck.
if _, ok := s.engine.(*clique.Clique); ok {
return false
}
return s.isLocalBlock(block)
}
// SetEtherbase sets the mining reward address.
func (s *Ethereum) SetEtherbase(etherbase common.Address) {
s.lock.Lock()
s.etherbase = etherbase
s.lock.Unlock()
s.miner.SetEtherbase(etherbase)
}
// StartMining starts the miner with the given number of CPU threads. If mining
// is already running, this method adjust the number of threads allowed to use
// and updates the minimum price required by the transaction pool.
func (s *Ethereum) StartMining(threads int) error {
// Update the thread count within the consensus engine
type threaded interface {
SetThreads(threads int)
}
if th, ok := s.engine.(threaded); ok {
log.Info("Updated mining threads", "threads", threads)
if threads == 0 {
threads = -1 // Disable the miner from within
}
th.SetThreads(threads)
}
// If the miner was not running, initialize it
if !s.IsMining() {
// Propagate the initial price point to the transaction pool
s.lock.RLock()
price := s.gasPrice
s.lock.RUnlock()
s.txPool.SetGasPrice(price)
// Configure the local mining address
eb, err := s.Etherbase()
if err != nil {
log.Error("Cannot start mining without etherbase", "err", err)
return fmt.Errorf("etherbase missing: %v", err)
}
if clique, ok := s.engine.(*clique.Clique); ok {
wallet, err := s.accountManager.Find(accounts.Account{Address: eb})
if wallet == nil || err != nil {
log.Error("Etherbase account unavailable locally", "err", err)
return fmt.Errorf("signer missing: %v", err)
}
clique.Authorize(eb, wallet.SignData)
}
// If mining is started, we can disable the transaction rejection mechanism
// introduced to speed sync times.
atomic.StoreUint32(&s.protocolManager.acceptTxs, 1)
go s.miner.Start(eb)
}
return nil
}
// StopMining terminates the miner, both at the consensus engine level as well as
// at the block creation level.
func (s *Ethereum) StopMining() {
// Update the thread count within the consensus engine
type threaded interface {
SetThreads(threads int)
}
if th, ok := s.engine.(threaded); ok {
th.SetThreads(-1)
}
// Stop the block creating itself
s.miner.Stop()
}
func (s *Ethereum) IsMining() bool { return s.miner.Mining() }
func (s *Ethereum) Miner() *miner.Miner { return s.miner }
func (s *Ethereum) AccountManager() *accounts.Manager { return s.accountManager }
func (s *Ethereum) BlockChain() *core.BlockChain { return s.blockchain }
func (s *Ethereum) TxPool() *core.TxPool { return s.txPool }
func (s *Ethereum) EventMux() *event.TypeMux { return s.eventMux }
func (s *Ethereum) Engine() consensus.Engine { return s.engine }
func (s *Ethereum) ChainDb() ethdb.Database { return s.chainDb }
func (s *Ethereum) ChainKV() ethdb.KV { return s.chainKV }
func (s *Ethereum) IsListening() bool { return true } // Always listening
func (s *Ethereum) EthVersion() int { return int(ProtocolVersions[0]) }
func (s *Ethereum) NetVersion() uint64 { return s.networkID }
func (s *Ethereum) Downloader() *downloader.Downloader { return s.protocolManager.downloader }
func (s *Ethereum) Synced() bool { return atomic.LoadUint32(&s.protocolManager.acceptTxs) == 1 }
func (s *Ethereum) ArchiveMode() bool { return !s.config.Pruning }
// Protocols implements node.Service, returning all the currently configured
// network protocols to start.
func (s *Ethereum) Protocols() []p2p.Protocol {
protos := make([]p2p.Protocol, len(ProtocolVersions))
for i, vsn := range ProtocolVersions {
protos[i] = s.protocolManager.makeProtocol(vsn)
protos[i].Attributes = []enr.Entry{s.currentEthEntry()}
protos[i].DialCandidates = s.dialCandidates
}
if s.config.EnableDebugProtocol {
// Debug
protos = append(protos, s.protocolManager.makeDebugProtocol())
}
if s.lesServer != nil {
protos = append(protos, s.lesServer.Protocols()...)
}
return protos
}
// Start implements node.Service, starting all internal goroutines needed by the
// Ethereum protocol implementation.
func (s *Ethereum) Start(srvr *p2p.Server) error {
s.startEthEntryUpdate(srvr.LocalNode())
// Start the bloom bits servicing goroutines
if s.config.SyncMode != downloader.StagedSync {
s.startBloomHandlers(params.BloomBitsBlocks)
}
// Start the RPC service
if s.config.SyncMode != downloader.StagedSync {
s.netRPCService = ethapi.NewPublicNetAPI(srvr, s.NetVersion())
}
// Figure out a max peers count based on the server limits
maxPeers := srvr.MaxPeers
if s.config.LightServ > 0 {
if s.config.LightPeers >= srvr.MaxPeers {
return fmt.Errorf("invalid peer config: light peer count (%d) >= total peer count (%d)", s.config.LightPeers, srvr.MaxPeers)
}
maxPeers -= s.config.LightPeers
}
withTxPool := s.config.SyncMode != downloader.StagedSync
// Start the networking layer and the light server if requested
if err := s.protocolManager.Start(maxPeers, withTxPool); err != nil {
return err
}
if s.lesServer != nil {
s.lesServer.Start(srvr)
}
return nil
}
func (s *Ethereum) StartTxPool() error {
if s.txPoolStarted {
return errors.New("transaction pool is already started")
}
headHash := rawdb.ReadHeadHeaderHash(s.chainDb)
headNumber := rawdb.ReadHeaderNumber(s.chainDb, headHash)
head := rawdb.ReadHeader(s.chainDb, headHash, *headNumber)
if err := s.txPool.Start(head.GasLimit, *headNumber); err != nil {
return err
}
if err := s.protocolManager.StartTxPool(); err != nil {
s.txPool.Stop()
return err
}
s.txPoolStarted = true
return nil
}
func (s *Ethereum) StopTxPool() error {
if !s.txPoolStarted {
return errors.New("transaction pool is already stopped")
}
s.protocolManager.StopTxPool()
s.txPool.Stop()
s.txPoolStarted = false
return nil
}
// Stop implements node.Service, terminating all internal goroutines used by the
// Ethereum protocol.
func (s *Ethereum) Stop() error {
// Stop all the peer-related stuff first.
s.protocolManager.Stop()
if s.lesServer != nil {
s.lesServer.Stop()
}
// Then stop everything else.
s.bloomIndexer.Close()
close(s.closeBloomHandler)
if err := s.StopTxPool(); err != nil {
log.Warn("error while stopping transaction pool", "err", err)
}
s.miner.Stop()
s.blockchain.Stop()
s.engine.Close()
s.eventMux.Stop()
if s.txPool != nil {
s.txPool.Stop()
}
//s.chainDb.Close()
return nil
}