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eth, eth/downloader: Moved block processing & graceful shutdown

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The downloader is no longer responsible for processing blocks. The
eth-protocol handler now takes care of this instead.

Added graceful shutdown during block processing. Closes #846
This commit is contained in:
obscuren
2015-05-01 00:23:51 +02:00
parent 8595198c1b
commit 016f152b36
6 changed files with 347 additions and 291 deletions
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281
eth/downloader/downloader.go
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@ -3,14 +3,11 @@ package downloader
import (
"errors"
"fmt"
"math"
"math/big"
"sync"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
@ -27,16 +24,21 @@ var (
minDesiredPeerCount = 5 // Amount of peers desired to start syncing
blockTtl = 20 * time.Second // The amount of time it takes for a block request to time out
errLowTd = errors.New("peer's TD is too low")
errBusy = errors.New("busy")
errUnknownPeer = errors.New("peer's unknown or unhealthy")
ErrBadPeer = errors.New("action from bad peer ignored")
errTimeout = errors.New("timeout")
errEmptyHashSet = errors.New("empty hash set by peer")
errPeersUnavailable = errors.New("no peers available or all peers tried for block download process")
errLowTd = errors.New("peer's TD is too low")
errBusy = errors.New("busy")
errUnknownPeer = errors.New("peer's unknown or unhealthy")
ErrBadPeer = errors.New("action from bad peer ignored")
errNoPeers = errors.New("no peers to keep download active")
errPendingQueue = errors.New("pending items in queue")
errTimeout = errors.New("timeout")
errEmptyHashSet = errors.New("empty hash set by peer")
errPeersUnavailable = errors.New("no peers available or all peers tried for block download process")
errAlreadyInPool = errors.New("hash already in pool")
errBlockNumberOverflow = errors.New("received block which overflows")
)
type hashCheckFn func(common.Hash) bool
type getBlockFn func(common.Hash) *types.Block
type chainInsertFn func(types.Blocks) (int, error)
type hashIterFn func() (common.Hash, error)
@ -58,13 +60,12 @@ type Downloader struct {
activePeer string
// Callbacks
hasBlock hashCheckFn
insertChain chainInsertFn
hasBlock hashCheckFn
getBlock getBlockFn
// Status
fetchingHashes int32
downloadingBlocks int32
processingBlocks int32
// Channels
newPeerCh chan *peer
@ -72,15 +73,15 @@ type Downloader struct {
blockCh chan blockPack
}
func New(hasBlock hashCheckFn, insertChain chainInsertFn) *Downloader {
func New(hasBlock hashCheckFn, getBlock getBlockFn) *Downloader {
downloader := &Downloader{
queue: newqueue(),
peers: make(peers),
hasBlock: hasBlock,
insertChain: insertChain,
newPeerCh: make(chan *peer, 1),
hashCh: make(chan []common.Hash, 1),
blockCh: make(chan blockPack, 1),
queue: newqueue(),
peers: make(peers),
hasBlock: hasBlock,
getBlock: getBlock,
newPeerCh: make(chan *peer, 1),
hashCh: make(chan []common.Hash, 1),
blockCh: make(chan blockPack, 1),
}
return downloader
@ -126,6 +127,12 @@ func (d *Downloader) Synchronise(id string, hash common.Hash) error {
return errBusy
}
// When a synchronisation attempt is made while the queue stil
// contains items we abort the sync attempt
if d.queue.size() > 0 {
return errPendingQueue
}
// Fetch the peer using the id or throw an error if the peer couldn't be found
p := d.peers[id]
if p == nil {
@ -138,30 +145,87 @@ func (d *Downloader) Synchronise(id string, hash common.Hash) error {
return err
}
return d.process(p)
return nil
}
func (d *Downloader) getFromPeer(p *peer, hash common.Hash, ignoreInitial bool) error {
// Done lets the downloader know that whatever previous hashes were taken
// are processed. If the block count reaches zero and done is called
// we reset the queue for the next batch of incoming hashes and blocks.
func (d *Downloader) Done() {
d.queue.mu.Lock()
defer d.queue.mu.Unlock()
if len(d.queue.blocks) == 0 {
d.queue.resetNoTS()
}
}
// TakeBlocks takes blocks from the queue and yields them to the blockTaker handler
// it's possible it yields no blocks
func (d *Downloader) TakeBlocks() types.Blocks {
d.queue.mu.Lock()
defer d.queue.mu.Unlock()
var blocks types.Blocks
if len(d.queue.blocks) > 0 {
// Make sure the parent hash is known
if d.queue.blocks[0] != nil && !d.hasBlock(d.queue.blocks[0].ParentHash()) {
return nil
}
for _, block := range d.queue.blocks {
if block == nil {
break
}
blocks = append(blocks, block)
}
d.queue.blockOffset += len(blocks)
// delete the blocks from the slice and let them be garbage collected
// without this slice trick the blocks would stay in memory until nil
// would be assigned to d.queue.blocks
copy(d.queue.blocks, d.queue.blocks[len(blocks):])
for k, n := len(d.queue.blocks)-len(blocks), len(d.queue.blocks); k < n; k++ {
d.queue.blocks[k] = nil
}
d.queue.blocks = d.queue.blocks[:len(d.queue.blocks)-len(blocks)]
//d.queue.blocks = d.queue.blocks[len(blocks):]
if len(d.queue.blocks) == 0 {
d.queue.blocks = nil
}
}
return blocks
}
func (d *Downloader) Has(hash common.Hash) bool {
return d.queue.has(hash)
}
func (d *Downloader) getFromPeer(p *peer, hash common.Hash, ignoreInitial bool) (err error) {
d.activePeer = p.id
defer func() {
// reset on error
if err != nil {
d.queue.reset()
}
}()
glog.V(logger.Detail).Infoln("Synchronising with the network using:", p.id)
// Start the fetcher. This will block the update entirely
// interupts need to be send to the appropriate channels
// respectively.
if err := d.startFetchingHashes(p, hash, ignoreInitial); err != nil {
// handle error
glog.V(logger.Debug).Infoln("Error fetching hashes:", err)
// XXX Reset
if err = d.startFetchingHashes(p, hash, ignoreInitial); err != nil {
return err
}
// Start fetching blocks in paralel. The strategy is simple
// take any available peers, seserve a chunk for each peer available,
// let the peer deliver the chunkn and periodically check if a peer
// has timedout. When done downloading, process blocks.
if err := d.startFetchingBlocks(p); err != nil {
glog.V(logger.Debug).Infoln("Error downloading blocks:", err)
// XXX reset
// has timedout.
if err = d.startFetchingBlocks(p); err != nil {
return err
}
@ -175,6 +239,10 @@ func (d *Downloader) startFetchingHashes(p *peer, hash common.Hash, ignoreInitia
atomic.StoreInt32(&d.fetchingHashes, 1)
defer atomic.StoreInt32(&d.fetchingHashes, 0)
if d.queue.has(hash) {
return errAlreadyInPool
}
glog.V(logger.Debug).Infof("Downloading hashes (%x) from %s", hash.Bytes()[:4], p.id)
start := time.Now()
@ -196,10 +264,13 @@ out:
case hashes := <-d.hashCh:
failureResponseTimer.Reset(hashTtl)
var done bool // determines whether we're done fetching hashes (i.e. common hash found)
var (
done bool // determines whether we're done fetching hashes (i.e. common hash found)
hash common.Hash // current and common hash
)
hashSet := set.New()
for _, hash := range hashes {
if d.hasBlock(hash) {
for _, hash = range hashes {
if d.hasBlock(hash) || d.queue.has(hash) {
glog.V(logger.Debug).Infof("Found common hash %x\n", hash[:4])
done = true
@ -220,6 +291,14 @@ out:
// Get the next set of hashes
p.getHashes(hashes[len(hashes)-1])
} else { // we're done
// The offset of the queue is determined by the highest known block
var offset int
if block := d.getBlock(hash); block != nil {
offset = int(block.NumberU64() + 1)
}
// allocate proper size for the queueue
d.queue.alloc(offset, d.queue.hashPool.Size())
break out
}
case <-failureResponseTimer.C:
@ -257,11 +336,27 @@ out:
// If the peer was previously banned and failed to deliver it's pack
// in a reasonable time frame, ignore it's message.
if d.peers[blockPack.peerId] != nil {
err := d.queue.deliver(blockPack.peerId, blockPack.blocks)
if err != nil {
glog.V(logger.Debug).Infof("deliver failed for peer %s: %v\n", blockPack.peerId, err)
// FIXME d.UnregisterPeer(blockPack.peerId)
break
}
if glog.V(logger.Debug) {
glog.Infof("adding %d blocks from: %s\n", len(blockPack.blocks), blockPack.peerId)
}
d.peers[blockPack.peerId].promote()
d.queue.deliver(blockPack.peerId, blockPack.blocks)
d.peers.setState(blockPack.peerId, idleState)
}
case <-ticker.C:
// after removing bad peers make sure we actually have suffucient peer left to keep downlading
if len(d.peers) == 0 {
d.queue.reset()
return errNoPeers
}
// If there are unrequested hashes left start fetching
// from the available peers.
if d.queue.hashPool.Size() > 0 {
@ -310,7 +405,7 @@ out:
if time.Since(chunk.itime) > blockTtl {
badPeers = append(badPeers, pid)
// remove peer as good peer from peer list
//d.UnregisterPeer(pid)
// FIXME d.UnregisterPeer(pid)
}
}
d.queue.mu.Unlock()
@ -364,114 +459,6 @@ func (d *Downloader) AddHashes(id string, hashes []common.Hash) error {
return nil
}
// Add an (unrequested) block to the downloader. This is usually done through the
// NewBlockMsg by the protocol handler.
// Adding blocks is done synchronously. if there are missing blocks, blocks will be
// fetched first. If the downloader is busy or if some other processed failed an error
// will be returned.
func (d *Downloader) AddBlock(id string, block *types.Block, td *big.Int) error {
hash := block.Hash()
if d.hasBlock(hash) {
return fmt.Errorf("known block %x", hash.Bytes()[:4])
}
peer := d.peers.getPeer(id)
// if the peer is in our healthy list of peers; update the td
// and add the block. Otherwise just ignore it
if peer == nil {
glog.V(logger.Detail).Infof("Ignored block from bad peer %s\n", id)
return ErrBadPeer
}
peer.mu.Lock()
peer.recentHash = block.Hash()
peer.mu.Unlock()
peer.promote()
glog.V(logger.Detail).Infoln("Inserting new block from:", id)
d.queue.addBlock(id, block)
// if neither go ahead to process
if d.isBusy() {
return errBusy
}
// Check if the parent of the received block is known.
// If the block is not know, request it otherwise, request.
phash := block.ParentHash()
if !d.hasBlock(phash) {
glog.V(logger.Detail).Infof("Missing parent %x, requires fetching\n", phash.Bytes()[:4])
// Get the missing hashes from the peer (synchronously)
err := d.getFromPeer(peer, peer.recentHash, true)
if err != nil {
return err
}
}
return d.process(peer)
}
func (d *Downloader) process(peer *peer) error {
atomic.StoreInt32(&d.processingBlocks, 1)
defer atomic.StoreInt32(&d.processingBlocks, 0)
// XXX this will move when optimised
// Sort the blocks by number. This bit needs much improvement. Right now
// it assumes full honesty form peers (i.e. it's not checked when the blocks
// link). We should at least check whihc queue match. This code could move
// to a seperate goroutine where it periodically checks for linked pieces.
types.BlockBy(types.Number).Sort(d.queue.blocks)
if len(d.queue.blocks) == 0 {
return nil
}
var blocks = d.queue.blocks
glog.V(logger.Debug).Infof("Inserting chain with %d blocks (#%v - #%v)\n", len(blocks), blocks[0].Number(), blocks[len(blocks)-1].Number())
// Loop untill we're out of blocks
for len(blocks) != 0 {
max := int(math.Min(float64(len(blocks)), 256))
// TODO check for parent error. When there's a parent error we should stop
// processing and start requesting the `block.hash` so that it's parent and
// grandparents can be requested and queued.
var i int
i, err := d.insertChain(blocks[:max])
if err != nil && core.IsParentErr(err) {
// Ignore the missing blocks. Handler should take care of anything that's missing.
glog.V(logger.Debug).Infof("Ignored block with missing parent (%d)\n", i)
blocks = blocks[i+1:]
continue
} else if err != nil {
// immediatly unregister the false peer but do not disconnect
d.UnregisterPeer(d.activePeer)
// Reset chain completely. This needs much, much improvement.
// instead: check all blocks leading down to this block false block and remove it
d.queue.blocks = nil
return ErrBadPeer
}
// delete the blocks from the slice and let them be garbage collected
// without this slice trick the blocks would stay in memory until nil
// would be assigned to d.queue.blocks
copy(blocks, blocks[max:])
for k, n := len(blocks)-max, len(blocks); k < n; k++ {
blocks[k] = nil
}
blocks = blocks[:len(blocks)-max]
}
if len(blocks) == 0 {
d.queue.blocks = nil
} else {
d.queue.blocks = blocks
}
return nil
}
func (d *Downloader) isFetchingHashes() bool {
return atomic.LoadInt32(&d.fetchingHashes) == 1
}
@ -480,12 +467,8 @@ func (d *Downloader) isDownloadingBlocks() bool {
return atomic.LoadInt32(&d.downloadingBlocks) == 1
}
func (d *Downloader) isProcessing() bool {
return atomic.LoadInt32(&d.processingBlocks) == 1
}
func (d *Downloader) isBusy() bool {
return d.isFetchingHashes() || d.isDownloadingBlocks() || d.isProcessing()
return d.isFetchingHashes() || d.isDownloadingBlocks()
}
func (d *Downloader) IsBusy() bool {