plugeth/eth/sync.go
obscuren 05715f27cf eth: added a cancel method for the downloader
Added a cancel method to the downloader which gracefully shuts down any
active syncing process (hash fetching or block downloading) and resets
the queue and remove any pending blocks.

Issue with the downloader which would stall because of an active ongoing
process when an invalid block was found.
2015-05-10 00:34:07 +02:00

106 lines
3.0 KiB
Go

package eth
import (
"math"
"time"
"github.com/ethereum/go-ethereum/eth/downloader"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
)
// Sync contains all synchronisation code for the eth protocol
func (pm *ProtocolManager) update() {
forceSync := time.Tick(forceSyncCycle)
blockProc := time.Tick(blockProcCycle)
for {
select {
case <-pm.newPeerCh:
// Meet the `minDesiredPeerCount` before we select our best peer
if len(pm.peers) < minDesiredPeerCount {
break
}
// Find the best peer and synchronise with it
peer := getBestPeer(pm.peers)
if peer == nil {
glog.V(logger.Debug).Infoln("Sync attempt canceled. No peers available")
}
go pm.synchronise(peer)
case <-forceSync:
// Force a sync even if not enough peers are present
if peer := getBestPeer(pm.peers); peer != nil {
go pm.synchronise(peer)
}
case <-blockProc:
// Try to pull some blocks from the downloaded
go pm.processBlocks()
case <-pm.quitSync:
return
}
}
}
// processBlocks will attempt to reconstruct a chain by checking the first item and check if it's
// a known parent. The first block in the chain may be unknown during downloading. When the
// downloader isn't downloading blocks will be dropped with an unknown parent until either it
// has depleted the list or found a known parent.
func (pm *ProtocolManager) processBlocks() error {
pm.wg.Add(1)
defer pm.wg.Done()
// Take a batch of blocks (will return nil if a previous batch has not reached the chain yet)
blocks := pm.downloader.TakeBlocks()
if len(blocks) == 0 {
return nil
}
glog.V(logger.Debug).Infof("Inserting chain with %d blocks (#%v - #%v)\n", len(blocks), blocks[0].Number(), blocks[len(blocks)-1].Number())
for len(blocks) != 0 && !pm.quit {
max := int(math.Min(float64(len(blocks)), float64(blockProcAmount)))
_, err := pm.chainman.InsertChain(blocks[:max])
if err != nil {
// cancel download process
pm.downloader.Cancel()
return err
}
blocks = blocks[max:]
}
return nil
}
func (pm *ProtocolManager) synchronise(peer *peer) {
// Make sure the peer's TD is higher than our own. If not drop.
if peer.td.Cmp(pm.chainman.Td()) <= 0 {
return
}
// FIXME if we have the hash in our chain and the TD of the peer is
// much higher than ours, something is wrong with us or the peer.
// Check if the hash is on our own chain
if pm.chainman.HasBlock(peer.recentHash) {
return
}
// Get the hashes from the peer (synchronously)
glog.V(logger.Debug).Infof("Attempting synchronisation: %v, 0x%x", peer.id, peer.recentHash)
err := pm.downloader.Synchronise(peer.id, peer.recentHash)
switch err {
case nil:
glog.V(logger.Debug).Infof("Synchronisation completed")
case downloader.ErrBusy:
glog.V(logger.Debug).Infof("Synchronisation already in progress")
case downloader.ErrTimeout:
glog.V(logger.Debug).Infof("Removing peer %v due to sync timeout", peer.id)
pm.removePeer(peer)
default:
glog.V(logger.Warn).Infof("Synchronisation failed: %v", err)
}
}