以太坊原理分析系列4---挖矿模块
2019-07-16 本文已影响0人
JC86
先上挖矿流程图
image.png
miner、worker和agent是主要工作部件，关系如下
image.png
类图
image.png
Miner的定义如下
//Miner创建块并搜索工作证明值。
type Miner struct {
mux *event.TypeMux //接收来自downloader模块的StartEvent DoneEvent FailedEvent事件通知。在网络中，不可能只有一个矿工节点,当downloader开始从其他节点同步Block时，我们就没有必要再继续挖矿了
worker *worker //对应的worker,从这里看出Miner和worker是一一对应的
coinbase common.Address //本矿工的账户地址,挖矿所得的收入将计入该账户
eth Backend //通过该接口可查询后台TxPool BlockChain ethdb的数据.举例来说，作为矿工，我们在生成一个新的Block时需要从TxPool中取出pending Tx(待打包成块的交易),然后将它们中的一部分作为新的Block中的Transaction
engine consensus.Engine //采用的共识引擎,目前以太坊公网采用的是ethash,测试网络采用clique
exitCh chan struct{}
canStart int32 //can start指示是否可以启动挖掘操作
shouldStart int32 //should start指示是否应在同步后启动
}
看看他new一个miner的时候做了些什么
func New(eth Backend, config *params.ChainConfig, mux *event.TypeMux, engine consensus.Engine) *Miner {
miner := &Miner{
eth: eth,
mux: mux,
engine: engine,
worker: newWorker(config, engine, common.Address{}, eth, mux),
canStart: 1,
}
miner.Register(NewCpuAgent(eth.BlockChain(), engine))
go miner.update()
return miner
}
首先初始化了结构变量，然后还做了一下动作：
1、创建一个worker实例
2、使用miner.newCpuAgent()创建Agent 并用Register方法注册给worker
3、启动miner.update() 线程.该线程等待mux上的来自 downloader模块的事件通知用来控制挖矿开始或停止
func (self *Miner) Register(agent Agent) {
if self.Mining() {
agent.Start()
}
self.worker.register(agent)
}
func (self *worker) register(agent Agent) {
self.mu.Lock()
defer self.mu.Unlock()
self.agents[agent] = struct{}{}
agent.SetReturnCh(self.recv)
}
// worker is the main object which takes care of applying messages to the new state
type worker struct {
config *params.ChainConfig
engine consensus.Engine
mu sync.Mutex
// update loop
mux *event.TypeMux
txCh chan core.TxPreEvent
txSub event.Subscription
chainHeadCh chan core.ChainHeadEvent
chainHeadSub event.Subscription
chainSideCh chan core.ChainSideEvent
chainSideSub event.Subscription
wg sync.WaitGroup
agents map[Agent]struct{}
recv chan *Result
eth Backend
chain *core.BlockChain
proc core.Validator
chainDb ethdb.Database
coinbase common.Address
extra []byte
currentMu sync.Mutex
current *Work
uncleMu sync.Mutex
possibleUncles map[common.Hash]*types.Block
unconfirmed *unconfirmedBlocks // set of locally mined blocks pending canonicalness confirmations
// atomic status counters
mining int32
atWork int32
}
func newWorker(config *params.ChainConfig, engine consensus.Engine, coinbase common.Address, eth Backend, mux *event.TypeMux) *worker {
worker := &worker{
config: config,
engine: engine,
eth: eth,
mux: mux,
txCh: make(chan core.TxPreEvent, txChanSize),
chainHeadCh: make(chan core.ChainHeadEvent, chainHeadChanSize),
chainSideCh: make(chan core.ChainSideEvent, chainSideChanSize),
chainDb: eth.ChainDb(),
recv: make(chan *Result, resultQueueSize),
chain: eth.BlockChain(),
proc: eth.BlockChain().Validator(),
possibleUncles: make(map[common.Hash]*types.Block),
coinbase: coinbase,
agents: make(map[Agent]struct{}),
unconfirmed: newUnconfirmedBlocks(eth.BlockChain(), miningLogAtDepth),
}
// Subscribe TxPreEvent for tx pool
worker.txSub = eth.TxPool().SubscribeTxPreEvent(worker.txCh)
// Subscribe events for blockchain
worker.chainHeadSub = eth.BlockChain().SubscribeChainHeadEvent(worker.chainHeadCh)
worker.chainSideSub = eth.BlockChain().SubscribeChainSideEvent(worker.chainSideCh)
go worker.update()
go worker.wait()
worker.commitNewWork()
return worker
}
// Agent can register themself with the worker
type Agent interface {
Work() chan<- *Work
SetReturnCh(chan<- *Result)
Stop()
Start()
GetHashRate() int64
}
func (self *worker) commitNewWork() {
self.mu.Lock()
defer self.mu.Unlock()
self.uncleMu.Lock()
defer self.uncleMu.Unlock()
self.currentMu.Lock()
defer self.currentMu.Unlock()
tstart := time.Now()
parent := self.chain.CurrentBlock()
tstamp := tstart.Unix()
if parent.Time().Cmp(new(big.Int).SetInt64(tstamp)) >= 0 {
tstamp = parent.Time().Int64() + 1
}
// this will ensure we're not going off too far in the future
if now := time.Now().Unix(); tstamp > now+1 {
wait := time.Duration(tstamp-now) * time.Second
log.Info("Mining too far in the future", "wait", common.PrettyDuration(wait))
time.Sleep(wait)
}
num := parent.Number()
header := &types.Header{
ParentHash: parent.Hash(),
Number: num.Add(num, common.Big1),
GasLimit: core.CalcGasLimit(parent),
Extra: self.extra,
Time: big.NewInt(tstamp),
}
// Only set the coinbase if we are mining (avoid spurious block rewards)
if atomic.LoadInt32(&self.mining) == 1 {
header.Coinbase = self.coinbase
}
if err := self.engine.Prepare(self.chain, header); err != nil {
log.Error("Failed to prepare header for mining", "err", err)
return
}
// If we are care about TheDAO hard-fork check whether to override the extra-data or not
if daoBlock := self.config.DAOForkBlock; daoBlock != nil {
// Check whether the block is among the fork extra-override range
limit := new(big.Int).Add(daoBlock, params.DAOForkExtraRange)
if header.Number.Cmp(daoBlock) >= 0 && header.Number.Cmp(limit) < 0 {
// Depending whether we support or oppose the fork, override differently
if self.config.DAOForkSupport {
header.Extra = common.CopyBytes(params.DAOForkBlockExtra)
} else if bytes.Equal(header.Extra, params.DAOForkBlockExtra) {
header.Extra = []byte{} // If miner opposes, don't let it use the reserved extra-data
}
}
}
// Could potentially happen if starting to mine in an odd state.
err := self.makeCurrent(parent, header)
if err != nil {
log.Error("Failed to create mining context", "err", err)
return
}
// Create the current work task and check any fork transitions needed
work := self.current
if self.config.DAOForkSupport && self.config.DAOForkBlock != nil && self.config.DAOForkBlock.Cmp(header.Number) == 0 {
misc.ApplyDAOHardFork(work.state)
}
pending, err := self.eth.TxPool().Pending()
if err != nil {
log.Error("Failed to fetch pending transactions", "err", err)
return
}
txs := types.NewTransactionsByPriceAndNonce(self.current.signer, pending)
work.commitTransactions(self.mux, txs, self.chain, self.coinbase)
// compute uncles for the new block.
var (
uncles []*types.Header
badUncles []common.Hash
)
for hash, uncle := range self.possibleUncles {
if len(uncles) == 2 {
break
}
if err := self.commitUncle(work, uncle.Header()); err != nil {
log.Trace("Bad uncle found and will be removed", "hash", hash)
log.Trace(fmt.Sprint(uncle))
badUncles = append(badUncles, hash)
} else {
log.Debug("Committing new uncle to block", "hash", hash)
uncles = append(uncles, uncle.Header())
}
}
for _, hash := range badUncles {
delete(self.possibleUncles, hash)
}
// Create the new block to seal with the consensus engine
if work.Block, err = self.engine.Finalize(self.chain, header, work.state, work.txs, uncles, work.receipts); err != nil {
log.Error("Failed to finalize block for sealing", "err", err)
return
}
// We only care about logging if we're actually mining.
if atomic.LoadInt32(&self.mining) == 1 {
log.Info("Commit new mining work", "number", work.Block.Number(), "txs", work.tcount, "uncles", len(uncles), "elapsed", common.PrettyDuration(time.Since(tstart)))
self.unconfirmed.Shift(work.Block.NumberU64() - 1)
}
self.push(work)
}
func (env *Work) commitTransactions(mux *event.TypeMux, txs *types.TransactionsByPriceAndNonce, bc *core.BlockChain, coinbase common.Address) {
gp := new(core.GasPool).AddGas(env.header.GasLimit)
var coalescedLogs []*types.Log
for {
// If we don't have enough gas for any further transactions then we're done
if gp.Gas() < params.TxGas {
log.Trace("Not enough gas for further transactions", "gp", gp)
break
}
// Retrieve the next transaction and abort if all done
tx := txs.Peek()
if tx == nil {
break
}
// Error may be ignored here. The error has already been checked
// during transaction acceptance is the transaction pool.
//
// We use the eip155 signer regardless of the current hf.
from, _ := types.Sender(env.signer, tx)
// Check whether the tx is replay protected. If we're not in the EIP155 hf
// phase, start ignoring the sender until we do.
if tx.Protected() && !env.config.IsEIP155(env.header.Number) {
log.Trace("Ignoring reply protected transaction", "hash", tx.Hash(), "eip155", env.config.EIP155Block)
txs.Pop()
continue
}
// Start executing the transaction
env.state.Prepare(tx.Hash(), common.Hash{}, env.tcount)
err, logs := env.commitTransaction(tx, bc, coinbase, gp)
switch err {
case core.ErrGasLimitReached:
// Pop the current out-of-gas transaction without shifting in the next from the account
log.Trace("Gas limit exceeded for current block", "sender", from)
txs.Pop()
case core.ErrNonceTooLow:
// New head notification data race between the transaction pool and miner, shift
log.Trace("Skipping transaction with low nonce", "sender", from, "nonce", tx.Nonce())
txs.Shift()
case core.ErrNonceTooHigh:
// Reorg notification data race between the transaction pool and miner, skip account =
log.Trace("Skipping account with hight nonce", "sender", from, "nonce", tx.Nonce())
txs.Pop()
case nil:
// Everything ok, collect the logs and shift in the next transaction from the same account
coalescedLogs = append(coalescedLogs, logs...)
env.tcount++
txs.Shift()
default:
// Strange error, discard the transaction and get the next in line (note, the
// nonce-too-high clause will prevent us from executing in vain).
log.Debug("Transaction failed, account skipped", "hash", tx.Hash(), "err", err)
txs.Shift()
}
}
if len(coalescedLogs) > 0 || env.tcount > 0 {
// make a copy, the state caches the logs and these logs get "upgraded" from pending to mined
// logs by filling in the block hash when the block was mined by the local miner. This can
// cause a race condition if a log was "upgraded" before the PendingLogsEvent is processed.
cpy := make([]*types.Log, len(coalescedLogs))
for i, l := range coalescedLogs {
cpy[i] = new(types.Log)
*cpy[i] = *l
}
go func(logs []*types.Log, tcount int) {
if len(logs) > 0 {
mux.Post(core.PendingLogsEvent{Logs: logs})
}
if tcount > 0 {
mux.Post(core.PendingStateEvent{})
}
}(cpy, env.tcount)
}
}
