The agent is the object of specific mining. The process it performs is to accept the calculated block header, calculate the mixhash and nonce, and return the mined block header.
The CpuAgent is constructed. Generally, the CPU is not used for mining. Generally, mining is performed using a dedicated GPU for mining. The code for GPU mining will not be reflected here.
type CpuAgent struct {
mu sync.Mutex
workCh chan *Work // Accepting the channel for mining tasks
stop chan struct{}
quitCurrentOp chan struct{}
returnCh chan<- *Result // Return channel after mining completion
chain consensus.ChainReader // Get blockchain information
engine consensus.Engine // Consensus engine, here refers to the Pow engine
isMining int32 // isMining indicates whether the agent is currently mining
}
func NewCpuAgent(chain consensus.ChainReader, engine consensus.Engine) *CpuAgent {
miner := &CpuAgent{
chain: chain,
engine: engine,
stop: make(chan struct{}, 1),
workCh: make(chan *Work, 1),
}
return miner
}Set the return value channel and get the Work channel to facilitate the external value and get the return information.
func (self *CpuAgent) Work() chan<- *Work { return self.workCh }
func (self *CpuAgent) SetReturnCh(ch chan<- *Result) { self.returnCh = ch }Start and message loop, if you have started mining, then exit directly, otherwise start update goroutine update accept tasks from workCh, mine, or accept exit information, exit.
func (self *CpuAgent) Start() {
if !atomic.CompareAndSwapInt32(&self.isMining, 0, 1) {
return // agent already started
}
go self.update()
}
func (self *CpuAgent) update() {
out:
for {
select {
case work := <-self.workCh:
self.mu.Lock()
if self.quitCurrentOp != nil {
close(self.quitCurrentOp)
}
self.quitCurrentOp = make(chan struct{})
go self.mine(work, self.quitCurrentOp)
self.mu.Unlock()
case <-self.stop:
self.mu.Lock()
if self.quitCurrentOp != nil {
close(self.quitCurrentOp)
self.quitCurrentOp = nil
}
self.mu.Unlock()
break out
}
}
}Mine, mining, call the consistency engine for mining, if the mining is successful, send the message to returnCh.
func (self *CpuAgent) mine(work *Work, stop <-chan struct{}) {
if result, err := self.engine.Seal(self.chain, work.Block, stop); result != nil {
log.Info("Successfully sealed new block", "number", result.Number(), "hash", result.Hash())
self.returnCh <- &Result{work, result}
} else {
if err != nil {
log.Warn("Block sealing failed", "err", err)
}
self.returnCh <- nil
}
}GetHashRate, this function returns the current HashRate.
func (self *CpuAgent) GetHashRate() int64 {
if pow, ok := self.engine.(consensus.PoW); ok {
return int64(pow.Hashrate())
}
return 0
}Remote_agent provides a set of RPC interfaces that enable remote miners to perform mining functions. For example, I have a mining machine. The inside of the mining machine does not run the Ethereum node. The mining machine first obtains the current task from remote_agent, and then performs mining calculation. When the mining is completed, the calculation result is submitted and the mining is completed.
Data structure and construction
type RemoteAgent struct {
mu sync.Mutex
quitCh chan struct{}
workCh chan *Work // accept the task
returnCh chan<- *Result // Result return
chain consensus.ChainReader
engine consensus.Engine
currentWork *Work // Current task
work map[common.Hash]*Work // Tasks that have not yet been submitted, are being calculated
hashrateMu sync.RWMutex
hashrate map[common.Hash]hashrate // Hashrate of the task being calculated
running int32 // running indicates whether the agent is active. Call atomically
}
func NewRemoteAgent(chain consensus.ChainReader, engine consensus.Engine) *RemoteAgent {
return &RemoteAgent{
chain: chain,
engine: engine,
work: make(map[common.Hash]*Work),
hashrate: make(map[common.Hash]hashrate),
}
}Start and stop
func (a *RemoteAgent) Start() {
if !atomic.CompareAndSwapInt32(&a.running, 0, 1) {
return
}
a.quitCh = make(chan struct{})
a.workCh = make(chan *Work, 1)
go a.loop(a.workCh, a.quitCh)
}
func (a *RemoteAgent) Stop() {
if !atomic.CompareAndSwapInt32(&a.running, 1, 0) {
return
}
close(a.quitCh)
close(a.workCh)
}Get the input and output channels, this is the same as agent.go.
func (a *RemoteAgent) Work() chan<- *Work {
return a.workCh
}
func (a *RemoteAgent) SetReturnCh(returnCh chan<- *Result) {
a.returnCh = returnCh
}The loop method is similar to the work done in agent.go. When the task is received, it is stored in the currentWork field. If you haven't completed a job in 84 seconds, then delete the job. If you haven't received the hashrate report for 10 seconds, delete the trace/.
// loop monitors mining events on the work and quit channels, updating the internal
// state of the rmeote miner until a termination is requested.
//
// Note, the reason the work and quit channels are passed as parameters is because
// RemoteAgent.Start() constantly recreates these channels, so the loop code cannot
// assume data stability in these member fields.
func (a *RemoteAgent) loop(workCh chan *Work, quitCh chan struct{}) {
ticker := time.NewTicker(5 * time.Second)
defer ticker.Stop()
for {
select {
case <-quitCh:
return
case work := <-workCh:
a.mu.Lock()
a.currentWork = work
a.mu.Unlock()
case <-ticker.C:
// cleanup
a.mu.Lock()
for hash, work := range a.work {
if time.Since(work.createdAt) > 7*(12*time.Second) {
delete(a.work, hash)
}
}
a.mu.Unlock()
a.hashrateMu.Lock()
for id, hashrate := range a.hashrate {
if time.Since(hashrate.ping) > 10*time.Second {
delete(a.hashrate, id)
}
}
a.hashrateMu.Unlock()
}
}
}GetWork, this method is called by a remote miner to get the current mining task.
func (a *RemoteAgent) GetWork() ([3]string, error) {
a.mu.Lock()
defer a.mu.Unlock()
var res [3]string
if a.currentWork != nil {
block := a.currentWork.Block
res[0] = block.HashNoNonce().Hex()
seedHash := ethash.SeedHash(block.NumberU64())
res[1] = common.BytesToHash(seedHash).Hex()
// Calculate the "target" to be returned to the external miner
n := big.NewInt(1)
n.Lsh(n, 255)
n.Div(n, block.Difficulty())
n.Lsh(n, 1)
res[2] = common.BytesToHash(n.Bytes()).Hex()
a.work[block.HashNoNonce()] = a.currentWork
return res, nil
}
return res, errors.New("No work available yet, don't panic.")
}SubmitWork, the remote miners call this method to submit the results of the mining. Submit the result to returnCh after verifying the result
// SubmitWork tries to inject a pow solution into the remote agent, returning
// whether the solution was accepted or not (not can be both a bad pow as well as
// any other error, like no work pending).
func (a *RemoteAgent) SubmitWork(nonce types.BlockNonce, mixDigest, hash common.Hash) bool {
a.mu.Lock()
defer a.mu.Unlock()
// Make sure the work submitted is present
work := a.work[hash]
if work == nil {
log.Info("Work submitted but none pending", "hash", hash)
return false
}
// Make sure the Engine solutions is indeed valid
result := work.Block.Header()
result.Nonce = nonce
result.MixDigest = mixDigest
if err := a.engine.VerifySeal(a.chain, result); err != nil {
log.Warn("Invalid proof-of-work submitted", "hash", hash, "err", err)
return false
}
block := work.Block.WithSeal(result)
// Solutions seems to be valid, return to the miner and notify acceptance
a.returnCh <- &Result{work, block}
delete(a.work, hash)
return true
}SubmitHashrate, submit hash power
func (a *RemoteAgent) SubmitHashrate(id common.Hash, rate uint64) {
a.hashrateMu.Lock()
defer a.hashrateMu.Unlock()
a.hashrate[id] = hashrate{time.Now(), rate}
}Unconfirmed is a data structure used to track the user's local mining information, such as dug out a block, then wait for enough subsequent block confirmation (5), then check whether the local mining block is included in the specification. Inside the blockchain.
Data structure
// headerRetriever is used by the unconfirmed block set to verify whether a previously
// mined block is part of the canonical chain or not.
type headerRetriever interface {
// GetHeaderByNumber retrieves the canonical header associated with a block number.
GetHeaderByNumber(number uint64) *types.Header
}
// unconfirmedBlock is a small collection of metadata about a locally mined block
// that is placed into a unconfirmed set for canonical chain inclusion tracking.
type unconfirmedBlock struct {
index uint64
hash common.Hash
}
// unconfirmedBlocks implements a data structure to maintain locally mined blocks
// have have not yet reached enough maturity to guarantee chain inclusion. It is
// used by the miner to provide logs to the user when a previously mined block
// has a high enough guarantee to not be reorged out of te canonical chain.
type unconfirmedBlocks struct {
chain headerRetriever // Blockchain to verify canonical status through
depth uint // Depth after which to discard previous blocks
blocks *ring.Ring // Block infos to allow canonical chain cross checks
lock sync.RWMutex // Protects the fields from concurrent access
}
// newUnconfirmedBlocks returns new data structure to track currently unconfirmed blocks.
func newUnconfirmedBlocks(chain headerRetriever, depth uint) *unconfirmedBlocks {
return &unconfirmedBlocks{
chain: chain,
depth: depth,
}
}Insert the tracking block, when the miner digs into a block, index is the height of the block, and hash is the hash value of the block.
// Insert adds a new block to the set of unconfirmed ones.
func (set *unconfirmedBlocks) Insert(index uint64, hash common.Hash) {
// If a new block was mined locally, shift out any old enough blocks
set.Shift(index)
// Create the new item as its own ring
item := ring.New(1)
item.Value = &unconfirmedBlock{
index: index,
hash: hash,
}
// Set as the initial ring or append to the end
set.lock.Lock()
defer set.lock.Unlock()
if set.blocks == nil {
set.blocks = item
} else {
// Move to the last element of the loop queue to insert the item
set.blocks.Move(-1).Link(item)
}
// Display a log for the user to notify of a new mined block unconfirmed
log.Info("🔨 mined potential block", "number", index, "hash", hash)
}The Shift method removes blocks whose index exceeds the passed index-depth and checks if they are in the canonical blockchain.
// Shift drops all unconfirmed blocks from the set which exceed the unconfirmed sets depth
// allowance, checking them against the canonical chain for inclusion or staleness
// report.
func (set *unconfirmedBlocks) Shift(height uint64) {
set.lock.Lock()
defer set.lock.Unlock()
for set.blocks != nil {
// Retrieve the next unconfirmed block and abort if too fresh
// Because the blocks in blocks are arranged in order. At the very beginning, it is definitely the oldest block.
// So only need to check the last block at a time, if it is finished, it will be removed from the loop queue.
next := set.blocks.Value.(*unconfirmedBlock)
if next.index+uint64(set.depth) > height { // If it is old enough.
break
}
// Block seems to exceed depth allowance, check for canonical status
// Query the block header of that block height
header := set.chain.GetHeaderByNumber(next.index)
switch {
case header == nil:
log.Warn("Failed to retrieve header of mined block", "number", next.index, "hash", next.hash)
case header.Hash() == next.hash: // If the block header is equal to ourselves,
log.Info("🔗 block reached canonical chain", "number", next.index, "hash", next.hash)
default: // Otherwise we are above the side chain.
log.Info("⑂ block became a side fork", "number", next.index, "hash", next.hash)
}
// Drop the block out of the ring
// Delete from the loop queue
if set.blocks.Value == set.blocks.Next().Value {
// If the current value is equal to our own, indicating that only the loop queue has only one element, then the setting is not nil
set.blocks = nil
} else {
// Otherwise move to the end, then delete one and move to the front.
set.blocks = set.blocks.Move(-1)
set.blocks.Unlink(1)
set.blocks = set.blocks.Move(1)
}
}
}The worker contains a lot of agents, including the agent and remote_agent mentioned earlier. The worker is also responsible for building blocks and objects. At the same time, the task is provided to the agent.
Data structure:
Agent interface
// Agent can register themself with the worker
type Agent interface {
Work() chan<- *Work
SetReturnCh(chan<- *Result)
Stop()
Start()
GetHashRate() int64
}Work structure, Work stores the worker's current environment and holds all temporary status information.
// Work is the workers current environment and holds
// all of the current state information
type Work struct {
config *params.ChainConfig
signer types.Signer // Signer
state *state.StateDB // apply state changes here
ancestors *set.Set // ancestor set (used for checking uncle parent validity)
family *set.Set // family set (used for checking uncle invalidity)
uncles *set.Set // uncle set
tcount int // tx count in cycle
Block *types.Block // the new block
header *types.Header // Block head
txs []*types.Transaction // transaction
receipts []*types.Receipt // receipt
createdAt time.Time // creation time
}
type Result struct {
Work *Work
Block *types.Block
}worker
// 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 // Channel used to accept transactions in txPool
txSub event.Subscription // Subscriber for accepting transactions in txPool
chainHeadCh chan core.ChainHeadEvent // Channel used to accept the block header
chainHeadSub event.Subscription
chainSideCh chan core.ChainSideEvent // Channel used to accept a blockchain removed from the canonical blockchain
chainSideSub event.Subscription
wg sync.WaitGroup
agents map[Agent]struct{} // All agents
recv chan *Result // Agent will send the result to this channel
eth Backend // Eth consensus
chain *core.BlockChain
proc core.Validator // blockchain validator
chainDb ethdb.Database // blockchain database
coinbase common.Address // Miner's address
extra []byte //
snapshotMu sync.RWMutex // Snapshot RWMutex (snapshot read and write lock)
snapshotBlock *types.Block
snapshotState *state.StateDB
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
}structure
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), // 4096
chainHeadCh: make(chan core.ChainHeadEvent, chainHeadChanSize), // 10
chainSideCh: make(chan core.ChainSideEvent, chainSideChanSize), // 10
chainDb: eth.ChainDb(),
recv: make(chan *Result, resultQueueSize), // 10
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
}update
func (self *worker) update() {
defer self.txSub.Unsubscribe()
defer self.chainHeadSub.Unsubscribe()
defer self.chainSideSub.Unsubscribe()
for {
// A real event arrived, process interesting content
select {
// Handle ChainHeadEvent When receiving the information of a block header, the mining service is started immediately.
case <-self.chainHeadCh:
self.commitNewWork()
// Handle ChainSideEvent Receive blocks that are not in the canonical blockchain and join the potential uncle collection
case ev := <-self.chainSideCh:
self.uncleMu.Lock()
self.possibleUncles[ev.Block.Hash()] = ev.Block
self.uncleMu.Unlock()
// Handle TxPreEvent When receiving the transaction information in txPool.
case ev := <-self.txCh:
// Apply transaction to the pending state if we're not mining
// If there is currently no mining, then apply the transaction to the current state so that the mining task can be started immediately.
if atomic.LoadInt32(&self.mining) == 0 {
self.currentMu.Lock()
acc, _ := types.Sender(self.current.signer, ev.Tx)
txs := map[common.Address]types.Transactions{acc: {ev.Tx}}
txset := types.NewTransactionsByPriceAndNonce(self.current.signer, txs)
self.current.commitTransactions(self.mux, txset, self.chain, self.coinbase)
self.currentMu.Unlock()
}
// System stopped
case <-self.txSub.Err():
return
case <-self.chainHeadSub.Err():
return
case <-self.chainSideSub.Err():
return
}
}
}commitNewWork submits a new task
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 { // can't appear less than the time of the parent
tstamp = parent.Time().Int64() + 1
}
// this will ensure we're not going off too far in the future
// Our time should not be too far away from the present time, then wait for a while,
// I feel that this function is completely for testing. If it is a real mining program, it should not wait.
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),
GasUsed: new(big.Int),
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
// Check if the block is within the range of DAO hard fork [daoblock,daoblock+limit]
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 { // If we support DAO then set the reserved extra data
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) // Use the new block header to set the current state
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) // Transfer funds from the DAO to the designated account.
}
pending, err := self.eth.TxPool().Pending() // Obstructed funds
if err != nil {
log.Error("Failed to fetch pending transactions", "err", err)
return
}
// Create a transaction. Follow-up of this method
txs := types.NewTransactionsByPriceAndNonce(self.current.signer, pending)
// Submit a transaction
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
// Use the given state to create a new block, Finalize will perform block rewards, etc.
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)
}Push method, if we are not mining, then return directly, otherwise give the task to each agent
// push sends a new work task to currently live miner agents.
func (self *worker) push(work *Work) {
if atomic.LoadInt32(&self.mining) != 1 {
return
}
for agent := range self.agents {
atomic.AddInt32(&self.atWork, 1)
if ch := agent.Work(); ch != nil {
ch <- work
}
}
}makeCurrent, creating a new environment without the current cycle.
// makeCurrent creates a new environment for the current cycle.
//
func (self *worker) makeCurrent(parent *types.Block, header *types.Header) error {
state, err := self.chain.StateAt(parent.Root())
if err != nil {
return err
}
work := &Work{
config: self.config,
signer: types.NewEIP155Signer(self.config.ChainId),
state: state,
ancestors: set.New(),
family: set.New(),
uncles: set.New(),
header: header,
createdAt: time.Now(),
}
// when 08 is processed ancestors contain 07 (quick block)
for _, ancestor := range self.chain.GetBlocksFromHash(parent.Hash(), 7) {
for _, uncle := range ancestor.Uncles() {
work.family.Add(uncle.Hash())
}
work.family.Add(ancestor.Hash())
work.ancestors.Add(ancestor.Hash())
}
// Keep track of transactions which return errors so they can be removed
work.tcount = 0
self.current = work
return nil
}commitTransactions
func (env *Work) commitTransactions(mux *event.TypeMux, txs *types.TransactionsByPriceAndNonce, bc *core.BlockChain, coinbase common.Address) {
// Initialize the total gasPool to env.header.GasLimit because it is a new block in the package
if env.gasPool == nil {
env.gasPool = 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
// Exit the packaged transaction if all Gas consumption in the current block has been used up
if env.gasPool.Gas() < params.TxGas {
log.Trace("Not enough gas for further transactions", "have", env.gasPool, "want", params.TxGas)
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.
// Please refer to https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md
// After the DAO event, Ethereum splits into ETH and ETC, because the things on the two chains are the same, so at ETC
// The transaction that occurred above can be retrieved on ETH and vice versa. So Vitalik proposed EIP155 to avoid this situation.
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)
// execute the transaction
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)
}
}commitTransaction execute ApplyTransaction
func (env *Work) commitTransaction(tx *types.Transaction, bc *core.BlockChain, coinbase common.Address, gp *core.GasPool) (error, []*types.Log) {
snap := env.state.Snapshot()
receipt, _, err := core.ApplyTransaction(env.config, bc, &coinbase, gp, env.state, env.header, tx, env.header.GasUsed, vm.Config{})
if err != nil {
env.state.RevertToSnapshot(snap)
return err, nil
}
env.txs = append(env.txs, tx)
env.receipts = append(env.receipts, receipt)
return nil, receipt.Logs
}The wait function is used to accept the results of the mining and then write to the local blockchain and broadcast it through the eth protocol.
func (self *worker) wait() {
for {
mustCommitNewWork := true
for result := range self.recv {
atomic.AddInt32(&self.atWork, -1)
if result == nil {
continue
}
block := result.Block
work := result.Work
// Update the block hash in all logs since it is now available and not when the
// receipt/log of individual transactions were created.
for _, r := range work.receipts {
for _, l := range r.Logs {
l.BlockHash = block.Hash()
}
}
for _, log := range work.state.Logs() {
log.BlockHash = block.Hash()
}
stat, err := self.chain.WriteBlockAndState(block, work.receipts, work.state)
if err != nil {
log.Error("Failed writing block to chain", "err", err)
continue
}
// check if canon block and write transactions
if stat == core.CanonStatTy { // Description Blockchain that has been inserted into the specification
// implicit by posting ChainHeadEvent
// Because in this state, will send ChainHeadEvent, will trigger the code inside the update, this part of the code will commitNewWork, so there is no need to commit here.
mustCommitNewWork = false
}
// Broadcast the block and announce chain insertion event
self.mux.Post(core.NewMinedBlockEvent{Block: block})
var (
events []interface{}
logs = work.state.Logs()
)
events = append(events, core.ChainEvent{Block: block, Hash: block.Hash(), Logs: logs})
if stat == core.CanonStatTy {
events = append(events, core.ChainHeadEvent{Block: block})
}
self.chain.PostChainEvents(events, logs)
// Insert the block into the set of pending ones to wait for confirmations
self.unconfirmed.Insert(block.NumberU64(), block.Hash())
if mustCommitNewWork {
self.commitNewWork()
}
}
}
}Miner is used to manage workers, subscribe to external events, and control the start and stop of workers.
Data structure
// Backend wraps all methods required for mining.
type Backend interface {
AccountManager() *accounts.Manager
BlockChain() *core.BlockChain
TxPool() *core.TxPool
ChainDb() ethdb.Database
}
// Miner creates blocks and searches for proof-of-work values.
type Miner struct {
mux *event.TypeMux
worker *worker
coinbase common.Address
mining int32
eth Backend
engine consensus.Engine
canStart int32 // can start indicates whether we can start the mining operation
shouldStart int32 // should start indicates whether we should start after sync
}Constructed, created a CPU agent started miner update goroutine
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
}Update subscribes to the downloader event. Note that this goroutine is a one-time loop. Once you receive a downloader's downloader.DoneEvent or downloader.FailedEvent event, it will set canStart to 1. and exit the loop. This is to avoid hackers. DOS attack, keep you in an abnormal state
// update keeps track of the downloader events. Please be aware that this is a one shot type of update loop.
// It's entered once and as soon as `Done` or `Failed` has been broadcasted the events are unregistered and
// the loop is exited. This to prevent a major security vuln where external parties can DOS you with blocks
// and halt your mining operation for as long as the DOS continues.
func (self *Miner) update() {
events := self.mux.Subscribe(downloader.StartEvent{}, downloader.DoneEvent{}, downloader.FailedEvent{})
out:
for ev := range events.Chan() {
switch ev.Data.(type) {
case downloader.StartEvent:
atomic.StoreInt32(&self.canStart, 0)
if self.Mining() {
self.Stop()
atomic.StoreInt32(&self.shouldStart, 1)
log.Info("Mining aborted due to sync")
}
case downloader.DoneEvent, downloader.FailedEvent:
shouldStart := atomic.LoadInt32(&self.shouldStart) == 1
atomic.StoreInt32(&self.canStart, 1)
atomic.StoreInt32(&self.shouldStart, 0)
if shouldStart {
self.Start(self.coinbase)
}
// unsubscribe. we're only interested in this event once
events.Unsubscribe()
// stop immediately and ignore all further pending events
break out
}
}
}Start
func (self *Miner) Start(coinbase common.Address) {
atomic.StoreInt32(&self.shouldStart, 1) // shouldStart should be started
self.worker.setEtherbase(coinbase)
self.coinbase = coinbase
if atomic.LoadInt32(&self.canStart) == 0 { // canStart can be started,
log.Info("Network syncing, will start miner afterwards")
return
}
atomic.StoreInt32(&self.mining, 1)
log.Info("Starting mining operation")
self.worker.start() // Start the worker to start mining
self.worker.commitNewWork() // submit a new work
}