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eth, eth/fetcher: separate notification sync mechanism

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This commit is contained in:
Péter Szilágyi 2015-06-16 11:58:32 +03:00
parent 2cea410656
commit 7c2af1c117
4 changed files with 293 additions and 182 deletions
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1
eth/downloader/downloader.go
View File

@ -1,3 +1,4 @@
// Package downloader contains the manual full chain synchronisation.
package downloader
import (

258
eth/fetcher/fetcher.go Normal file
View File

@ -0,0 +1,258 @@
// Package fetcher contains the block announcement based synchonisation.
package fetcher
import (
"errors"
"math/rand"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
)
const (
arriveTimeout = 500 * time.Millisecond // Time allowance before an announced block is explicitly requested
fetchTimeout = 5 * time.Second // Maximum alloted time to return an explicitly requested block
)
var (
errTerminated = errors.New("terminated")
)
// hashCheckFn is a callback type for verifying a hash's presence in the local chain.
type hashCheckFn func(common.Hash) bool
// blockRequesterFn is a callback type for sending a block retrieval request.
type blockRequesterFn func([]common.Hash) error
// blockImporterFn is a callback type for trying to inject a block into the local chain.
type blockImporterFn func(peer string, block *types.Block) error
// announce is the hash notification of the availability of a new block in the
// network.
type announce struct {
hash common.Hash // Hash of the block being announced
time time.Time // Timestamp of the announcement
origin string // Identifier of the peer originating the notification
fetch blockRequesterFn // Fetcher function to retrieve
}
// Fetcher is responsible for accumulating block announcements from various peers
// and scheduling them for retrieval.
type Fetcher struct {
// Various event channels
notify chan *announce
filter chan chan []*types.Block
quit chan struct{}
// Callbacks
hasBlock hashCheckFn // Checks if a block is present in the chain
importBlock blockImporterFn // Injects a block from an origin peer into the chain
}
// New creates a block fetcher to retrieve blocks based on hash announcements.
func New(hasBlock hashCheckFn, importBlock blockImporterFn) *Fetcher {
return &Fetcher{
notify: make(chan *announce),
filter: make(chan chan []*types.Block),
quit: make(chan struct{}),
hasBlock: hasBlock,
importBlock: importBlock,
}
}
// Start boots up the announcement based synchoniser, accepting and processing
// hash notifications and block fetches until termination requested.
func (f *Fetcher) Start() {
go f.loop()
}
// Stop terminates the announcement based synchroniser, canceling all pending
// operations.
func (f *Fetcher) Stop() {
close(f.quit)
}
// Notify announces the fetcher of the potential availability of a new block in
// the network.
func (f *Fetcher) Notify(peer string, hash common.Hash, time time.Time, fetcher blockRequesterFn) error {
block := &announce{
hash: hash,
time: time,
origin: peer,
fetch: fetcher,
}
select {
case f.notify <- block:
return nil
case <-f.quit:
return errTerminated
}
}
// Filter extracts all the blocks that were explicitly requested by the fetcher,
// returning those that should be handled differently.
func (f *Fetcher) Filter(blocks types.Blocks) types.Blocks {
// Send the filter channel to the fetcher
filter := make(chan []*types.Block)
select {
case f.filter <- filter:
case <-f.quit:
return nil
}
// Request the filtering of the block list
select {
case filter <- blocks:
case <-f.quit:
return nil
}
// Retrieve the blocks remaining after filtering
select {
case blocks := <-filter:
return blocks
case <-f.quit:
return nil
}
}
// Loop is the main fetcher loop, checking and processing various notification
// events.
func (f *Fetcher) loop() {
announced := make(map[common.Hash][]*announce)
fetching := make(map[common.Hash]*announce)
fetch := time.NewTimer(0)
done := make(chan common.Hash)
// Iterate the block fetching until a quit is requested
for {
// Clean up any expired block fetches
for hash, announce := range fetching {
if time.Since(announce.time) > fetchTimeout {
delete(announced, hash)
delete(fetching, hash)
}
}
// Wait for an outside event to occur
select {
case <-f.quit:
// Fetcher terminating, abort all operations
return
case notification := <-f.notify:
// A block was announced, schedule if it's not yet downloading
glog.V(logger.Debug).Infof("Peer %s: scheduling %x", notification.origin, notification.hash[:4])
if _, ok := fetching[notification.hash]; ok {
break
}
if len(announced) == 0 {
fetch.Reset(arriveTimeout)
}
announced[notification.hash] = append(announced[notification.hash], notification)
case hash := <-done:
// A pending import finished, remove all traces of the notification
delete(announced, hash)
delete(fetching, hash)
case <-fetch.C:
// At least one block's timer ran out, check for needing retrieval
request := make(map[string][]common.Hash)
for hash, announces := range announced {
if time.Since(announces[0].time) > arriveTimeout {
announce := announces[rand.Intn(len(announces))]
if !f.hasBlock(hash) {
request[announce.origin] = append(request[announce.origin], hash)
fetching[hash] = announce
}
delete(announced, hash)
}
}
// Send out all block requests
for peer, hashes := range request {
glog.V(logger.Debug).Infof("Peer %s: explicitly fetching %d blocks", peer, len(hashes))
go fetching[hashes[0]].fetch(hashes)
}
// Schedule the next fetch if blocks are still pending
if len(announced) > 0 {
nearest := time.Now()
for _, announces := range announced {
if nearest.Before(announces[0].time) {
nearest = announces[0].time
}
}
fetch.Reset(arriveTimeout + time.Since(nearest))
}
case filter := <-f.filter:
// Blocks arrived, extract any explicit fetches, return all else
var blocks types.Blocks
select {
case blocks = <-filter:
case <-f.quit:
return
}
explicit, download := []*types.Block{}, []*types.Block{}
for _, block := range blocks {
hash := block.Hash()
// Filter explicitly requested blocks from hash announcements
if _, ok := fetching[hash]; ok {
// Discard if already imported by other means
if !f.hasBlock(hash) {
explicit = append(explicit, block)
} else {
delete(fetching, hash)
}
} else {
download = append(download, block)
}
}
select {
case filter <- download:
case <-f.quit:
return
}
// Create a closure with the retrieved blocks and origin peers
peers := make([]string, 0, len(explicit))
blocks = make([]*types.Block, 0, len(explicit))
for _, block := range explicit {
hash := block.Hash()
if announce := fetching[hash]; announce != nil {
// Drop the block if it surely cannot fit
if f.hasBlock(hash) || !f.hasBlock(block.ParentHash()) {
// delete(fetching, hash) // if we drop, it will re-fetch it, wait for timeout?
continue
}
// Otherwise accumulate for import
peers = append(peers, announce.origin)
blocks = append(blocks, block)
}
}
// If any explicit fetches were replied to, import them
if count := len(blocks); count > 0 {
glog.V(logger.Debug).Infof("Importing %d explicitly fetched blocks", len(blocks))
go func() {
// Make sure all hashes are cleaned up
for _, block := range blocks {
hash := block.Hash()
defer func() { done <- hash }()
}
// Try and actually import the blocks
for i := 0; i < len(blocks); i++ {
if err := f.importBlock(peers[i], blocks[i]); err != nil {
glog.V(logger.Detail).Infof("Failed to import explicitly fetched block: %v", err)
return
}
}
}()
}
}
}
}

49
eth/handler.go
View File

@ -7,6 +7,8 @@ import (
"sync"
"time"
"github.com/ethereum/go-ethereum/eth/fetcher"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
@ -45,6 +47,7 @@ type ProtocolManager struct {
txpool txPool
chainman *core.ChainManager
downloader *downloader.Downloader
fetcher *fetcher.Fetcher
peers *peerSet
SubProtocol p2p.Protocol
@ -55,8 +58,6 @@ type ProtocolManager struct {
// channels for fetcher, syncer, txsyncLoop
newPeerCh chan *peer
newHashCh chan []*blockAnnounce
newBlockCh chan chan []*types.Block
txsyncCh chan *txsync
quitSync chan struct{}
@ -69,30 +70,33 @@ type ProtocolManager struct {
// NewProtocolManager returns a new ethereum sub protocol manager. The Ethereum sub protocol manages peers capable
// with the ethereum network.
func NewProtocolManager(protocolVersion, networkId int, mux *event.TypeMux, txpool txPool, chainman *core.ChainManager) *ProtocolManager {
// Create the protocol manager and initialize peer handlers
manager := &ProtocolManager{
eventMux: mux,
txpool: txpool,
chainman: chainman,
peers: newPeerSet(),
newPeerCh: make(chan *peer, 1),
newHashCh: make(chan []*blockAnnounce, 1),
newBlockCh: make(chan chan []*types.Block),
txsyncCh: make(chan *txsync),
quitSync: make(chan struct{}),
}
manager.downloader = downloader.New(manager.eventMux, manager.chainman.HasBlock, manager.chainman.GetBlock, manager.chainman.InsertChain, manager.removePeer)
manager.SubProtocol = p2p.Protocol{
Name: "eth",
Version: uint(protocolVersion),
Length: ProtocolLength,
Run: func(p *p2p.Peer, rw p2p.MsgReadWriter) error {
peer := manager.newPeer(protocolVersion, networkId, p, rw)
manager.newPeerCh <- peer
return manager.handle(peer)
},
}
// Construct the different synchronisation mechanisms
manager.downloader = downloader.New(manager.eventMux, manager.chainman.HasBlock, manager.chainman.GetBlock, manager.chainman.InsertChain, manager.removePeer)
importer := func(peer string, block *types.Block) error {
return manager.importBlock(manager.peers.Peer(peer), block, nil)
}
manager.fetcher = fetcher.New(manager.chainman.HasBlock, importer)
return manager
}
@ -126,7 +130,6 @@ func (pm *ProtocolManager) Start() {
// start sync handlers
go pm.syncer()
go pm.fetcher()
go pm.txsyncLoop()
}
@ -291,21 +294,10 @@ func (self *ProtocolManager) handleMsg(p *peer) error {
glog.V(logger.Detail).Infoln("Decode error", err)
blocks = nil
}
// Filter out any explicitly requested blocks (cascading select to get blocking back to peer)
filter := make(chan []*types.Block)
select {
case <-self.quitSync:
case self.newBlockCh <- filter:
select {
case <-self.quitSync:
case filter <- blocks:
select {
case <-self.quitSync:
case blocks := <-filter:
// Filter out any explicitly requested blocks, deliver the rest to the downloader
if blocks := self.fetcher.Filter(blocks); len(blocks) > 0 {
self.downloader.DeliverBlocks(p.id, blocks)
}
}
}
case NewBlockHashesMsg:
// Retrieve and deseralize the remote new block hashes notification
@ -327,19 +319,8 @@ func (self *ProtocolManager) handleMsg(p *peer) error {
unknown = append(unknown, hash)
}
}
announces := make([]*blockAnnounce, len(unknown))
for i, hash := range unknown {
announces[i] = &blockAnnounce{
hash: hash,
peer: p,
time: time.Now(),
}
}
if len(announces) > 0 {
select {
case self.newHashCh <- announces:
case <-self.quitSync:
}
for _, hash := range unknown {
self.fetcher.Notify(p.id, hash, time.Now(), p.requestBlocks)
}
case NewBlockMsg:

141
eth/sync.go
View File

@ -13,9 +13,6 @@ import (
const (
forceSyncCycle = 10 * time.Second // Time interval to force syncs, even if few peers are available
notifyCheckCycle = 100 * time.Millisecond // Time interval to allow hash notifies to fulfill before hard fetching
notifyArriveTimeout = 500 * time.Millisecond // Time allowance before an announced block is explicitly requested
notifyFetchTimeout = 5 * time.Second // Maximum alloted time to return an explicitly requested block
minDesiredPeerCount = 5 // Amount of peers desired to start syncing
// This is the target size for the packs of transactions sent by txsyncLoop.
@ -119,140 +116,15 @@ func (pm *ProtocolManager) txsyncLoop() {
}
}
// fetcher is responsible for collecting hash notifications, and periodically
// checking all unknown ones and individually fetching them.
func (pm *ProtocolManager) fetcher() {
announces := make(map[common.Hash][]*blockAnnounce)
request := make(map[*peer][]common.Hash)
pending := make(map[common.Hash]*blockAnnounce)
cycle := time.Tick(notifyCheckCycle)
done := make(chan common.Hash)
// Iterate the block fetching until a quit is requested
for {
select {
case notifications := <-pm.newHashCh:
// A batch of hashes the notified, schedule them for retrieval
glog.V(logger.Debug).Infof("Scheduling %d hash announcements from %s", len(notifications), notifications[0].peer.id)
for _, announce := range notifications {
// Skip if it's already pending fetch
if _, ok := pending[announce.hash]; ok {
continue
}
// Otherwise queue up the peer as a potential source
announces[announce.hash] = append(announces[announce.hash], announce)
}
case hash := <-done:
// A pending import finished, remove all traces
delete(pending, hash)
case <-cycle:
// Clean up any expired block fetches
for hash, announce := range pending {
if time.Since(announce.time) > notifyFetchTimeout {
delete(pending, hash)
}
}
// Check if any notified blocks failed to arrive
for hash, all := range announces {
if time.Since(all[0].time) > notifyArriveTimeout {
announce := all[rand.Intn(len(all))]
if !pm.chainman.HasBlock(hash) {
request[announce.peer] = append(request[announce.peer], hash)
pending[hash] = announce
}
delete(announces, hash)
}
}
if len(request) == 0 {
break
}
// Send out all block requests
for peer, hashes := range request {
glog.V(logger.Debug).Infof("Explicitly fetching %d blocks from %s", len(hashes), peer.id)
go peer.requestBlocks(hashes)
}
request = make(map[*peer][]common.Hash)
case filter := <-pm.newBlockCh:
// Blocks arrived, extract any explicit fetches, return all else
var blocks types.Blocks
select {
case blocks = <-filter:
case <-pm.quitSync:
return
}
explicit, download := []*types.Block{}, []*types.Block{}
for _, block := range blocks {
hash := block.Hash()
// Filter explicitly requested blocks from hash announcements
if _, ok := pending[hash]; ok {
// Discard if already imported by other means
if !pm.chainman.HasBlock(hash) {
explicit = append(explicit, block)
} else {
delete(pending, hash)
}
} else {
download = append(download, block)
}
}
select {
case filter <- download:
case <-pm.quitSync:
return
}
// Create a closure with the retrieved blocks and origin peers
peers := make([]*peer, 0, len(explicit))
blocks = make([]*types.Block, 0, len(explicit))
for _, block := range explicit {
hash := block.Hash()
if announce := pending[hash]; announce != nil {
// Drop the block if it surely cannot fit
if pm.chainman.HasBlock(hash) || !pm.chainman.HasBlock(block.ParentHash()) {
// delete(pending, hash) // if we drop, it will re-fetch it, wait for timeout?
continue
}
// Otherwise accumulate for import
peers = append(peers, announce.peer)
blocks = append(blocks, block)
}
}
// If any explicit fetches were replied to, import them
if count := len(blocks); count > 0 {
glog.V(logger.Debug).Infof("Importing %d explicitly fetched blocks", len(blocks))
go func() {
// Make sure all hashes are cleaned up
for _, block := range blocks {
hash := block.Hash()
defer func() { done <- hash }()
}
// Try and actually import the blocks
for i := 0; i < len(blocks); i++ {
if err := pm.importBlock(peers[i], blocks[i], nil); err != nil {
glog.V(logger.Detail).Infof("Failed to import explicitly fetched block: %v", err)
return
}
}
}()
}
case <-pm.quitSync:
return
}
}
}
// syncer is responsible for periodically synchronising with the network, both
// downloading hashes and blocks as well as retrieving cached ones.
// downloading hashes and blocks as well as handling the announcement handler.
func (pm *ProtocolManager) syncer() {
// Abort any pending syncs if we terminate
// Start and ensure cleanup of sync mechanisms
pm.fetcher.Start()
defer pm.fetcher.Stop()
defer pm.downloader.Terminate()
// Wait for different events to fire synchronisation operations
forceSync := time.Tick(forceSyncCycle)
for {
select {
@ -273,8 +145,7 @@ func (pm *ProtocolManager) syncer() {
}
}
// synchronise tries to sync up our local block chain with a remote peer, both
// adding various sanity checks as well as wrapping it with various log entries.
// synchronise tries to sync up our local block chain with a remote peer.
func (pm *ProtocolManager) synchronise(peer *peer) {
// Short circuit if no peers are available
if peer == nil {