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eth/fetcher: build longest chain until proven otherwise

This commit is contained in:
Péter Szilágyi 2015-06-17 16:53:28 +03:00
parent 2a7411bc96
commit 37c5ff392f
3 changed files with 95 additions and 31 deletions
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67
eth/fetcher/fetcher.go
View File

@ -3,7 +3,6 @@ package fetcher
import (
"errors"
"math"
"math/rand"
"time"
@ -57,8 +56,9 @@ type inject struct {
type Fetcher struct {
// Various event channels
notify chan *announce
insert chan *inject
inject chan *inject
filter chan chan []*types.Block
done chan common.Hash
quit chan struct{}
// Announce states
@ -79,8 +79,9 @@ type Fetcher struct {
func New(hasBlock hashCheckFn, importBlock blockImporterFn, chainHeight chainHeightFn) *Fetcher {
return &Fetcher{
notify: make(chan *announce),
insert: make(chan *inject),
inject: make(chan *inject),
filter: make(chan chan []*types.Block),
done: make(chan common.Hash),
quit: make(chan struct{}),
announced: make(map[common.Hash][]*announce),
fetching: make(map[common.Hash]*announce),
@ -128,7 +129,7 @@ func (f *Fetcher) Enqueue(peer string, block *types.Block) error {
block: block,
}
select {
case f.insert <- op:
case f.inject <- op:
return nil
case <-f.quit:
return errTerminated
@ -166,8 +167,6 @@ func (f *Fetcher) Filter(blocks types.Blocks) types.Blocks {
func (f *Fetcher) loop() {
// Iterate the block fetching until a quit is requested
fetch := time.NewTimer(0)
done := make(chan common.Hash)
for {
// Clean up any expired block fetches
for hash, announce := range f.fetching {
@ -179,27 +178,19 @@ func (f *Fetcher) loop() {
// Import any queued blocks that could potentially fit
height := f.chainHeight()
for !f.queue.Empty() {
// If too high up the chain, continue later
op := f.queue.PopItem().(*inject)
if number := op.block.NumberU64(); number > height+1 {
number := op.block.NumberU64()
// If too high up the chain or phase, continue later
if number > height+1 {
f.queue.Push(op, -float32(op.block.NumberU64()))
break
}
// Otherwise if not known yet, try and import
hash := op.block.Hash()
if f.hasBlock(hash) {
// Otherwise if fresh and still unknown, try and import
if number <= height || f.hasBlock(op.block.Hash()) {
continue
}
// Block may just fit, try to import it
glog.V(logger.Debug).Infof("Peer %s: importing block #%d [%x]", op.origin, op.block.NumberU64(), hash.Bytes()[:4])
go func() {
defer func() { done <- hash }()
if err := f.importBlock(op.origin, op.block); err != nil {
glog.V(logger.Detail).Infof("Peer %s: block #%d [%x] import failed: %v", op.origin, op.block.NumberU64(), hash.Bytes()[:4], err)
return
}
}()
f.insert(op.origin, op.block)
}
// Wait for an outside event to occur
select {
@ -209,7 +200,6 @@ func (f *Fetcher) loop() {
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 := f.fetching[notification.hash]; ok {
break
}
@ -218,11 +208,11 @@ func (f *Fetcher) loop() {
f.reschedule(fetch)
}
case op := <-f.insert:
case op := <-f.inject:
// A direct block insertion was requested, try and fill any pending gaps
f.enqueue(op.origin, op.block)
case hash := <-done:
case hash := <-f.done:
// A pending import finished, remove all traces of the notification
delete(f.announced, hash)
delete(f.fetching, hash)
@ -243,8 +233,7 @@ func (f *Fetcher) loop() {
}
}
// Send out all block requests
for peer, hashes := range request {
glog.V(logger.Debug).Infof("Peer %s: explicitly fetching %d blocks", peer, len(hashes))
for _, hashes := range request {
go f.fetching[hashes[0]].fetch(hashes)
}
// Schedule the next fetch if blocks are still pending
@ -304,7 +293,6 @@ func (f *Fetcher) reschedule(fetch *time.Timer) {
earliest = announces[0].time
}
}
glog.V(logger.Detail).Infof("Scheduling next fetch in %v", arriveTimeout-time.Since(earliest))
fetch.Reset(arriveTimeout - time.Since(earliest))
}
@ -313,9 +301,9 @@ func (f *Fetcher) reschedule(fetch *time.Timer) {
func (f *Fetcher) enqueue(peer string, block *types.Block) {
hash := block.Hash()
// Make sure the block isn't in some weird place
if math.Abs(float64(f.chainHeight())-float64(block.NumberU64())) > maxQueueDist {
glog.Infof("Peer %s: discarded block #%d [%x] too far from head", peer, block.NumberU64(), hash.Bytes()[:4])
// Discard any past or too distant blocks
if dist := int64(block.NumberU64()) - int64(f.chainHeight()); dist <= 0 || dist > maxQueueDist {
glog.Infof("Peer %s: discarded block #%d [%x], distance %d", peer, block.NumberU64(), hash.Bytes()[:4], dist)
return
}
// Schedule the block for future importing
@ -328,3 +316,22 @@ func (f *Fetcher) enqueue(peer string, block *types.Block) {
}
}
}
// insert spawns a new goroutine to run a block insertion into the chain. If the
// block's number is at the same height as the current import phase, if updates
// the phase states accordingly.
func (f *Fetcher) insert(peer string, block *types.Block) {
hash := block.Hash()
// Run the import on a new thread
glog.V(logger.Debug).Infof("Peer %s: importing block #%d [%x]", peer, block.NumberU64(), hash[:4])
go func() {
defer func() { f.done <- hash }()
// Run the actual import and log any issues
if err := f.importBlock(peer, block); err != nil {
glog.V(logger.Detail).Infof("Peer %s: block #%d [%x] import failed: %v", peer, block.NumberU64(), hash[:4], err)
return
}
}()
}

57
eth/fetcher/fetcher_test.go
View File

@ -91,9 +91,15 @@ func (f *fetcherTester) hasBlock(hash common.Hash) bool {
// importBlock injects a new blocks into the simulated chain.
func (f *fetcherTester) importBlock(peer string, block *types.Block) error {
// Make sure the parent in known
if _, ok := f.ownBlocks[block.ParentHash()]; !ok {
return errors.New("unknown parent")
}
// Discard any new blocks if the same height already exists
if block.NumberU64() <= f.ownBlocks[f.ownHashes[len(f.ownHashes)-1]].NumberU64() {
return nil
}
// Otherwise build our current chain
f.ownHashes = append(f.ownHashes, block.Hash())
f.ownBlocks[block.Hash()] = block
return nil
@ -363,3 +369,54 @@ func TestDistantDiscarding(t *testing.T) {
t.Fatalf("fetcher queued future block")
}
}
// Tests that if multiple uncles (i.e. blocks at the same height) are queued for
// importing, then they will get inserted in phases, previous heights needing to
// complete before the next numbered blocks can begin.
func TestCompetingImports(t *testing.T) {
// Generate a few soft-forks for concurrent imports
hashesA := createHashes(16, knownHash)
hashesB := createHashes(16, knownHash)
hashesC := createHashes(16, knownHash)
blocksA := createBlocksFromHashes(hashesA)
blocksB := createBlocksFromHashes(hashesB)
blocksC := createBlocksFromHashes(hashesC)
// Create a tester, and override the import to check number reversals
tester := newTester()
first := int32(1)
height := uint64(1)
tester.fetcher.importBlock = func(peer string, block *types.Block) error {
// Check for any phase reordering
if prev := atomic.LoadUint64(&height); block.NumberU64() < prev {
t.Errorf("phase reversal: have %v, want %v", block.NumberU64(), prev)
}
atomic.StoreUint64(&height, block.NumberU64())
// Sleep a bit on the first import not to race with the enqueues
if atomic.CompareAndSwapInt32(&first, 1, 0) {
time.Sleep(50 * time.Millisecond)
}
return tester.importBlock(peer, block)
}
// Queue up everything but with a missing link
for i := 0; i < len(hashesA)-2; i++ {
tester.fetcher.Enqueue("chain A", blocksA[hashesA[i]])
tester.fetcher.Enqueue("chain B", blocksB[hashesB[i]])
tester.fetcher.Enqueue("chain C", blocksC[hashesC[i]])
}
// Add the three missing links, and wait for a full import
tester.fetcher.Enqueue("chain A", blocksA[hashesA[len(hashesA)-2]])
tester.fetcher.Enqueue("chain B", blocksB[hashesB[len(hashesB)-2]])
tester.fetcher.Enqueue("chain C", blocksC[hashesC[len(hashesC)-2]])
start := time.Now()
for len(tester.ownHashes) != len(hashesA) && time.Since(start) < time.Second {
time.Sleep(50 * time.Millisecond)
}
if len(tester.ownHashes) != len(hashesA) {
t.Fatalf("chain length mismatch: have %v, want %v", len(tester.ownHashes), len(hashesA))
}
}

2
eth/handler.go
View File

@ -8,11 +8,11 @@ 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"
"github.com/ethereum/go-ethereum/eth/downloader"
"github.com/ethereum/go-ethereum/eth/fetcher"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"