plugeth/eth/backend.go
2015-06-30 19:05:06 +03:00

710 lines
22 KiB
Go

package eth
import (
"crypto/ecdsa"
"encoding/json"
"fmt"
"io/ioutil"
"math/big"
"os"
"path/filepath"
"strings"
"time"
"github.com/ethereum/ethash"
"github.com/ethereum/go-ethereum/accounts"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/compiler"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/eth/downloader"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/miner"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/discover"
"github.com/ethereum/go-ethereum/p2p/nat"
"github.com/ethereum/go-ethereum/whisper"
)
const (
epochLength = 30000
ethashRevision = 23
autoDAGcheckInterval = 10 * time.Hour
autoDAGepochHeight = epochLength / 2
)
var (
jsonlogger = logger.NewJsonLogger()
defaultBootNodes = []*discover.Node{
// ETH/DEV Go Bootnodes
discover.MustParseNode("enode://a979fb575495b8d6db44f750317d0f4622bf4c2aa3365d6af7c284339968eef29b69ad0dce72a4d8db5ebb4968de0e3bec910127f134779fbcb0cb6d3331163c@52.16.188.185:30303"),
discover.MustParseNode("enode://de471bccee3d042261d52e9bff31458daecc406142b401d4cd848f677479f73104b9fdeb090af9583d3391b7f10cb2ba9e26865dd5fca4fcdc0fb1e3b723c786@54.94.239.50:30303"),
// ETH/DEV cpp-ethereum (poc-9.ethdev.com)
discover.MustParseNode("enode://487611428e6c99a11a9795a6abe7b529e81315ca6aad66e2a2fc76e3adf263faba0d35466c2f8f68d561dbefa8878d4df5f1f2ddb1fbeab7f42ffb8cd328bd4a@5.1.83.226:30303"),
}
staticNodes = "static-nodes.json" // Path within <datadir> to search for the static node list
trustedNodes = "trusted-nodes.json" // Path within <datadir> to search for the trusted node list
)
type Config struct {
Name string
NetworkId int
GenesisNonce int
BlockChainVersion int
SkipBcVersionCheck bool // e.g. blockchain export
DataDir string
LogFile string
Verbosity int
LogJSON string
VmDebug bool
NatSpec bool
AutoDAG bool
MaxPeers int
MaxPendingPeers int
Discovery bool
Port string
// Space-separated list of discovery node URLs
BootNodes string
// This key is used to identify the node on the network.
// If nil, an ephemeral key is used.
NodeKey *ecdsa.PrivateKey
NAT nat.Interface
Shh bool
Dial bool
Etherbase string
GasPrice *big.Int
MinerThreads int
AccountManager *accounts.Manager
SolcPath string
GpoMinGasPrice *big.Int
GpoMaxGasPrice *big.Int
GpoFullBlockRatio int
GpobaseStepDown int
GpobaseStepUp int
GpobaseCorrectionFactor int
// NewDB is used to create databases.
// If nil, the default is to create leveldb databases on disk.
NewDB func(path string) (common.Database, error)
}
func (cfg *Config) parseBootNodes() []*discover.Node {
if cfg.BootNodes == "" {
return defaultBootNodes
}
var ns []*discover.Node
for _, url := range strings.Split(cfg.BootNodes, " ") {
if url == "" {
continue
}
n, err := discover.ParseNode(url)
if err != nil {
glog.V(logger.Error).Infof("Bootstrap URL %s: %v\n", url, err)
continue
}
ns = append(ns, n)
}
return ns
}
// parseNodes parses a list of discovery node URLs loaded from a .json file.
func (cfg *Config) parseNodes(file string) []*discover.Node {
// Short circuit if no node config is present
path := filepath.Join(cfg.DataDir, file)
if _, err := os.Stat(path); err != nil {
return nil
}
// Load the nodes from the config file
blob, err := ioutil.ReadFile(path)
if err != nil {
glog.V(logger.Error).Infof("Failed to access nodes: %v", err)
return nil
}
nodelist := []string{}
if err := json.Unmarshal(blob, &nodelist); err != nil {
glog.V(logger.Error).Infof("Failed to load nodes: %v", err)
return nil
}
// Interpret the list as a discovery node array
var nodes []*discover.Node
for _, url := range nodelist {
if url == "" {
continue
}
node, err := discover.ParseNode(url)
if err != nil {
glog.V(logger.Error).Infof("Node URL %s: %v\n", url, err)
continue
}
nodes = append(nodes, node)
}
return nodes
}
func (cfg *Config) nodeKey() (*ecdsa.PrivateKey, error) {
// use explicit key from command line args if set
if cfg.NodeKey != nil {
return cfg.NodeKey, nil
}
// use persistent key if present
keyfile := filepath.Join(cfg.DataDir, "nodekey")
key, err := crypto.LoadECDSA(keyfile)
if err == nil {
return key, nil
}
// no persistent key, generate and store a new one
if key, err = crypto.GenerateKey(); err != nil {
return nil, fmt.Errorf("could not generate server key: %v", err)
}
if err := crypto.SaveECDSA(keyfile, key); err != nil {
glog.V(logger.Error).Infoln("could not persist nodekey: ", err)
}
return key, nil
}
type Ethereum struct {
// Channel for shutting down the ethereum
shutdownChan chan bool
// DB interfaces
blockDb common.Database // Block chain database
stateDb common.Database // State changes database
extraDb common.Database // Extra database (txs, etc)
// Closed when databases are flushed and closed
databasesClosed chan bool
//*** SERVICES ***
// State manager for processing new blocks and managing the over all states
blockProcessor *core.BlockProcessor
txPool *core.TxPool
chainManager *core.ChainManager
accountManager *accounts.Manager
whisper *whisper.Whisper
pow *ethash.Ethash
protocolManager *ProtocolManager
SolcPath string
solc *compiler.Solidity
GpoMinGasPrice *big.Int
GpoMaxGasPrice *big.Int
GpoFullBlockRatio int
GpobaseStepDown int
GpobaseStepUp int
GpobaseCorrectionFactor int
net *p2p.Server
eventMux *event.TypeMux
miner *miner.Miner
// logger logger.LogSystem
Mining bool
MinerThreads int
NatSpec bool
DataDir string
AutoDAG bool
autodagquit chan bool
etherbase common.Address
clientVersion string
netVersionId int
shhVersionId int
}
func New(config *Config) (*Ethereum, error) {
// Bootstrap database
logger.New(config.DataDir, config.LogFile, config.Verbosity)
if len(config.LogJSON) > 0 {
logger.NewJSONsystem(config.DataDir, config.LogJSON)
}
// Let the database take 3/4 of the max open files (TODO figure out a way to get the actual limit of the open files)
const dbCount = 3
ethdb.OpenFileLimit = 128 / (dbCount + 1)
newdb := config.NewDB
if newdb == nil {
newdb = func(path string) (common.Database, error) { return ethdb.NewLDBDatabase(path) }
}
blockDb, err := newdb(filepath.Join(config.DataDir, "blockchain"))
if err != nil {
return nil, fmt.Errorf("blockchain db err: %v", err)
}
if db, ok := blockDb.(*ethdb.LDBDatabase); ok {
db.GetTimer = metrics.NewTimer("eth/db/block/user/gets")
db.PutTimer = metrics.NewTimer("eth/db/block/user/puts")
db.MissMeter = metrics.NewMeter("eth/db/block/user/misses")
db.ReadMeter = metrics.NewMeter("eth/db/block/user/reads")
db.WriteMeter = metrics.NewMeter("eth/db/block/user/writes")
db.CompTimeMeter = metrics.NewMeter("eth/db/block/compact/time")
db.CompReadMeter = metrics.NewMeter("eth/db/block/compact/input")
db.CompWriteMeter = metrics.NewMeter("eth/db/block/compact/output")
}
stateDb, err := newdb(filepath.Join(config.DataDir, "state"))
if err != nil {
return nil, fmt.Errorf("state db err: %v", err)
}
if db, ok := stateDb.(*ethdb.LDBDatabase); ok {
db.GetTimer = metrics.NewTimer("eth/db/state/user/gets")
db.PutTimer = metrics.NewTimer("eth/db/state/user/puts")
db.MissMeter = metrics.NewMeter("eth/db/state/user/misses")
db.ReadMeter = metrics.NewMeter("eth/db/state/user/reads")
db.WriteMeter = metrics.NewMeter("eth/db/state/user/writes")
db.CompTimeMeter = metrics.NewMeter("eth/db/state/compact/time")
db.CompReadMeter = metrics.NewMeter("eth/db/state/compact/input")
db.CompWriteMeter = metrics.NewMeter("eth/db/state/compact/output")
}
extraDb, err := newdb(filepath.Join(config.DataDir, "extra"))
if err != nil {
return nil, fmt.Errorf("extra db err: %v", err)
}
if db, ok := extraDb.(*ethdb.LDBDatabase); ok {
db.GetTimer = metrics.NewTimer("eth/db/extra/user/gets")
db.PutTimer = metrics.NewTimer("eth/db/extra/user/puts")
db.MissMeter = metrics.NewMeter("eth/db/extra/user/misses")
db.ReadMeter = metrics.NewMeter("eth/db/extra/user/reads")
db.WriteMeter = metrics.NewMeter("eth/db/extra/user/writes")
db.CompTimeMeter = metrics.NewMeter("eth/db/extra/compact/time")
db.CompReadMeter = metrics.NewMeter("eth/db/extra/compact/input")
db.CompWriteMeter = metrics.NewMeter("eth/db/extra/compact/output")
}
nodeDb := filepath.Join(config.DataDir, "nodes")
// Perform database sanity checks
/*
// The databases were previously tied to protocol versions. Currently we
// are moving away from this decision as approaching Frontier. The below
// check was left in for now but should eventually be just dropped.
d, _ := blockDb.Get([]byte("ProtocolVersion"))
protov := int(common.NewValue(d).Uint())
if protov != config.ProtocolVersion && protov != 0 {
path := filepath.Join(config.DataDir, "blockchain")
return nil, fmt.Errorf("Database version mismatch. Protocol(%d / %d). `rm -rf %s`", protov, config.ProtocolVersion, path)
}
saveProtocolVersion(blockDb, config.ProtocolVersion)
*/
glog.V(logger.Info).Infof("Protocol Versions: %v, Network Id: %v", ProtocolVersions, config.NetworkId)
if !config.SkipBcVersionCheck {
b, _ := blockDb.Get([]byte("BlockchainVersion"))
bcVersion := int(common.NewValue(b).Uint())
if bcVersion != config.BlockChainVersion && bcVersion != 0 {
return nil, fmt.Errorf("Blockchain DB version mismatch (%d / %d). Run geth upgradedb.\n", bcVersion, config.BlockChainVersion)
}
saveBlockchainVersion(blockDb, config.BlockChainVersion)
}
glog.V(logger.Info).Infof("Blockchain DB Version: %d", config.BlockChainVersion)
eth := &Ethereum{
shutdownChan: make(chan bool),
databasesClosed: make(chan bool),
blockDb: blockDb,
stateDb: stateDb,
extraDb: extraDb,
eventMux: &event.TypeMux{},
accountManager: config.AccountManager,
DataDir: config.DataDir,
etherbase: common.HexToAddress(config.Etherbase),
clientVersion: config.Name, // TODO should separate from Name
netVersionId: config.NetworkId,
NatSpec: config.NatSpec,
MinerThreads: config.MinerThreads,
SolcPath: config.SolcPath,
AutoDAG: config.AutoDAG,
GpoMinGasPrice: config.GpoMinGasPrice,
GpoMaxGasPrice: config.GpoMaxGasPrice,
GpoFullBlockRatio: config.GpoFullBlockRatio,
GpobaseStepDown: config.GpobaseStepDown,
GpobaseStepUp: config.GpobaseStepUp,
GpobaseCorrectionFactor: config.GpobaseCorrectionFactor,
}
eth.pow = ethash.New()
genesis := core.GenesisBlock(uint64(config.GenesisNonce), stateDb)
eth.chainManager, err = core.NewChainManager(genesis, blockDb, stateDb, eth.pow, eth.EventMux())
if err != nil {
return nil, err
}
eth.txPool = core.NewTxPool(eth.EventMux(), eth.chainManager.State, eth.chainManager.GasLimit)
eth.blockProcessor = core.NewBlockProcessor(stateDb, extraDb, eth.pow, eth.chainManager, eth.EventMux())
eth.chainManager.SetProcessor(eth.blockProcessor)
eth.protocolManager = NewProtocolManager(config.NetworkId, eth.eventMux, eth.txPool, eth.pow, eth.chainManager)
eth.miner = miner.New(eth, eth.EventMux(), eth.pow)
eth.miner.SetGasPrice(config.GasPrice)
if config.Shh {
eth.whisper = whisper.New()
eth.shhVersionId = int(eth.whisper.Version())
}
netprv, err := config.nodeKey()
if err != nil {
return nil, err
}
protocols := append([]p2p.Protocol{}, eth.protocolManager.SubProtocols...)
if config.Shh {
protocols = append(protocols, eth.whisper.Protocol())
}
eth.net = &p2p.Server{
PrivateKey: netprv,
Name: config.Name,
MaxPeers: config.MaxPeers,
MaxPendingPeers: config.MaxPendingPeers,
Discovery: config.Discovery,
Protocols: protocols,
NAT: config.NAT,
NoDial: !config.Dial,
BootstrapNodes: config.parseBootNodes(),
StaticNodes: config.parseNodes(staticNodes),
TrustedNodes: config.parseNodes(trustedNodes),
NodeDatabase: nodeDb,
}
if len(config.Port) > 0 {
eth.net.ListenAddr = ":" + config.Port
}
vm.Debug = config.VmDebug
return eth, nil
}
type NodeInfo struct {
Name string
NodeUrl string
NodeID string
IP string
DiscPort int // UDP listening port for discovery protocol
TCPPort int // TCP listening port for RLPx
Td string
ListenAddr string
}
func (s *Ethereum) NodeInfo() *NodeInfo {
node := s.net.Self()
return &NodeInfo{
Name: s.Name(),
NodeUrl: node.String(),
NodeID: node.ID.String(),
IP: node.IP.String(),
DiscPort: int(node.UDP),
TCPPort: int(node.TCP),
ListenAddr: s.net.ListenAddr,
Td: s.ChainManager().Td().String(),
}
}
type PeerInfo struct {
ID string
Name string
Caps string
RemoteAddress string
LocalAddress string
}
func newPeerInfo(peer *p2p.Peer) *PeerInfo {
var caps []string
for _, cap := range peer.Caps() {
caps = append(caps, cap.String())
}
return &PeerInfo{
ID: peer.ID().String(),
Name: peer.Name(),
Caps: strings.Join(caps, ", "),
RemoteAddress: peer.RemoteAddr().String(),
LocalAddress: peer.LocalAddr().String(),
}
}
// PeersInfo returns an array of PeerInfo objects describing connected peers
func (s *Ethereum) PeersInfo() (peersinfo []*PeerInfo) {
for _, peer := range s.net.Peers() {
if peer != nil {
peersinfo = append(peersinfo, newPeerInfo(peer))
}
}
return
}
func (s *Ethereum) ResetWithGenesisBlock(gb *types.Block) {
s.chainManager.ResetWithGenesisBlock(gb)
}
func (s *Ethereum) StartMining(threads int) error {
eb, err := s.Etherbase()
if err != nil {
err = fmt.Errorf("Cannot start mining without etherbase address: %v", err)
glog.V(logger.Error).Infoln(err)
return err
}
go s.miner.Start(eb, threads)
return nil
}
func (s *Ethereum) Etherbase() (eb common.Address, err error) {
eb = s.etherbase
if (eb == common.Address{}) {
primary, err := s.accountManager.Primary()
if err != nil {
return eb, err
}
if (primary == common.Address{}) {
err = fmt.Errorf("no accounts found")
return eb, err
}
eb = primary
}
return eb, nil
}
func (s *Ethereum) StopMining() { s.miner.Stop() }
func (s *Ethereum) IsMining() bool { return s.miner.Mining() }
func (s *Ethereum) Miner() *miner.Miner { return s.miner }
// func (s *Ethereum) Logger() logger.LogSystem { return s.logger }
func (s *Ethereum) Name() string { return s.net.Name }
func (s *Ethereum) AccountManager() *accounts.Manager { return s.accountManager }
func (s *Ethereum) ChainManager() *core.ChainManager { return s.chainManager }
func (s *Ethereum) BlockProcessor() *core.BlockProcessor { return s.blockProcessor }
func (s *Ethereum) TxPool() *core.TxPool { return s.txPool }
func (s *Ethereum) Whisper() *whisper.Whisper { return s.whisper }
func (s *Ethereum) EventMux() *event.TypeMux { return s.eventMux }
func (s *Ethereum) BlockDb() common.Database { return s.blockDb }
func (s *Ethereum) StateDb() common.Database { return s.stateDb }
func (s *Ethereum) ExtraDb() common.Database { return s.extraDb }
func (s *Ethereum) IsListening() bool { return true } // Always listening
func (s *Ethereum) PeerCount() int { return s.net.PeerCount() }
func (s *Ethereum) Peers() []*p2p.Peer { return s.net.Peers() }
func (s *Ethereum) MaxPeers() int { return s.net.MaxPeers }
func (s *Ethereum) ClientVersion() string { return s.clientVersion }
func (s *Ethereum) EthVersion() int { return int(s.protocolManager.SubProtocols[0].Version) }
func (s *Ethereum) NetVersion() int { return s.netVersionId }
func (s *Ethereum) ShhVersion() int { return s.shhVersionId }
func (s *Ethereum) Downloader() *downloader.Downloader { return s.protocolManager.downloader }
// Start the ethereum
func (s *Ethereum) Start() error {
jsonlogger.LogJson(&logger.LogStarting{
ClientString: s.net.Name,
ProtocolVersion: s.EthVersion(),
})
err := s.net.Start()
if err != nil {
return err
}
// periodically flush databases
go s.syncDatabases()
if s.AutoDAG {
s.StartAutoDAG()
}
s.protocolManager.Start()
if s.whisper != nil {
s.whisper.Start()
}
glog.V(logger.Info).Infoln("Server started")
return nil
}
// sync databases every minute. If flushing fails we exit immediatly. The system
// may not continue under any circumstances.
func (s *Ethereum) syncDatabases() {
ticker := time.NewTicker(1 * time.Minute)
done:
for {
select {
case <-ticker.C:
// don't change the order of database flushes
if err := s.extraDb.Flush(); err != nil {
glog.Fatalf("fatal error: flush extraDb: %v (Restart your node. We are aware of this issue)\n", err)
}
if err := s.stateDb.Flush(); err != nil {
glog.Fatalf("fatal error: flush stateDb: %v (Restart your node. We are aware of this issue)\n", err)
}
if err := s.blockDb.Flush(); err != nil {
glog.Fatalf("fatal error: flush blockDb: %v (Restart your node. We are aware of this issue)\n", err)
}
case <-s.shutdownChan:
break done
}
}
s.blockDb.Close()
s.stateDb.Close()
s.extraDb.Close()
close(s.databasesClosed)
}
func (s *Ethereum) StartForTest() {
jsonlogger.LogJson(&logger.LogStarting{
ClientString: s.net.Name,
ProtocolVersion: s.EthVersion(),
})
}
// AddPeer connects to the given node and maintains the connection until the
// server is shut down. If the connection fails for any reason, the server will
// attempt to reconnect the peer.
func (self *Ethereum) AddPeer(nodeURL string) error {
n, err := discover.ParseNode(nodeURL)
if err != nil {
return fmt.Errorf("invalid node URL: %v", err)
}
self.net.AddPeer(n)
return nil
}
func (s *Ethereum) Stop() {
s.net.Stop()
s.chainManager.Stop()
s.protocolManager.Stop()
s.txPool.Stop()
s.eventMux.Stop()
if s.whisper != nil {
s.whisper.Stop()
}
s.StopAutoDAG()
close(s.shutdownChan)
}
// This function will wait for a shutdown and resumes main thread execution
func (s *Ethereum) WaitForShutdown() {
<-s.databasesClosed
<-s.shutdownChan
}
// StartAutoDAG() spawns a go routine that checks the DAG every autoDAGcheckInterval
// by default that is 10 times per epoch
// in epoch n, if we past autoDAGepochHeight within-epoch blocks,
// it calls ethash.MakeDAG to pregenerate the DAG for the next epoch n+1
// if it does not exist yet as well as remove the DAG for epoch n-1
// the loop quits if autodagquit channel is closed, it can safely restart and
// stop any number of times.
// For any more sophisticated pattern of DAG generation, use CLI subcommand
// makedag
func (self *Ethereum) StartAutoDAG() {
if self.autodagquit != nil {
return // already started
}
go func() {
glog.V(logger.Info).Infof("Automatic pregeneration of ethash DAG ON (ethash dir: %s)", ethash.DefaultDir)
var nextEpoch uint64
timer := time.After(0)
self.autodagquit = make(chan bool)
for {
select {
case <-timer:
glog.V(logger.Info).Infof("checking DAG (ethash dir: %s)", ethash.DefaultDir)
currentBlock := self.ChainManager().CurrentBlock().NumberU64()
thisEpoch := currentBlock / epochLength
if nextEpoch <= thisEpoch {
if currentBlock%epochLength > autoDAGepochHeight {
if thisEpoch > 0 {
previousDag, previousDagFull := dagFiles(thisEpoch - 1)
os.Remove(filepath.Join(ethash.DefaultDir, previousDag))
os.Remove(filepath.Join(ethash.DefaultDir, previousDagFull))
glog.V(logger.Info).Infof("removed DAG for epoch %d (%s)", thisEpoch-1, previousDag)
}
nextEpoch = thisEpoch + 1
dag, _ := dagFiles(nextEpoch)
if _, err := os.Stat(dag); os.IsNotExist(err) {
glog.V(logger.Info).Infof("Pregenerating DAG for epoch %d (%s)", nextEpoch, dag)
err := ethash.MakeDAG(nextEpoch*epochLength, "") // "" -> ethash.DefaultDir
if err != nil {
glog.V(logger.Error).Infof("Error generating DAG for epoch %d (%s)", nextEpoch, dag)
return
}
} else {
glog.V(logger.Error).Infof("DAG for epoch %d (%s)", nextEpoch, dag)
}
}
}
timer = time.After(autoDAGcheckInterval)
case <-self.autodagquit:
return
}
}
}()
}
// dagFiles(epoch) returns the two alternative DAG filenames (not a path)
// 1) <revision>-<hex(seedhash[8])> 2) full-R<revision>-<hex(seedhash[8])>
func dagFiles(epoch uint64) (string, string) {
seedHash, _ := ethash.GetSeedHash(epoch * epochLength)
dag := fmt.Sprintf("full-R%d-%x", ethashRevision, seedHash[:8])
return dag, "full-R" + dag
}
// stopAutoDAG stops automatic DAG pregeneration by quitting the loop
func (self *Ethereum) StopAutoDAG() {
if self.autodagquit != nil {
close(self.autodagquit)
self.autodagquit = nil
}
glog.V(logger.Info).Infof("Automatic pregeneration of ethash DAG OFF (ethash dir: %s)", ethash.DefaultDir)
}
/*
// The databases were previously tied to protocol versions. Currently we
// are moving away from this decision as approaching Frontier. The below
// code was left in for now but should eventually be just dropped.
func saveProtocolVersion(db common.Database, protov int) {
d, _ := db.Get([]byte("ProtocolVersion"))
protocolVersion := common.NewValue(d).Uint()
if protocolVersion == 0 {
db.Put([]byte("ProtocolVersion"), common.NewValue(protov).Bytes())
}
}
*/
func saveBlockchainVersion(db common.Database, bcVersion int) {
d, _ := db.Get([]byte("BlockchainVersion"))
blockchainVersion := common.NewValue(d).Uint()
if blockchainVersion == 0 {
db.Put([]byte("BlockchainVersion"), common.NewValue(bcVersion).Bytes())
}
}
func (self *Ethereum) Solc() (*compiler.Solidity, error) {
var err error
if self.solc == nil {
self.solc, err = compiler.New(self.SolcPath)
}
return self.solc, err
}
// set in js console via admin interface or wrapper from cli flags
func (self *Ethereum) SetSolc(solcPath string) (*compiler.Solidity, error) {
self.SolcPath = solcPath
self.solc = nil
return self.Solc()
}