prysm-pulse/beacon-chain/sync/initial-sync/service.go
2021-01-06 11:19:53 +00:00

230 lines
6.8 KiB
Go

// Package initialsync includes all initial block download and processing
// logic for the beacon node, using a round robin strategy and a finite-state-machine
// to handle edge-cases in a beacon node's sync status.
package initialsync
import (
"context"
"time"
"github.com/paulbellamy/ratecounter"
"github.com/pkg/errors"
"github.com/prysmaticlabs/prysm/beacon-chain/blockchain"
"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
blockfeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/block"
statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
"github.com/prysmaticlabs/prysm/beacon-chain/db"
"github.com/prysmaticlabs/prysm/beacon-chain/flags"
"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
"github.com/prysmaticlabs/prysm/shared"
"github.com/prysmaticlabs/prysm/shared/abool"
"github.com/prysmaticlabs/prysm/shared/params"
"github.com/prysmaticlabs/prysm/shared/timeutils"
"github.com/sirupsen/logrus"
)
var _ shared.Service = (*Service)(nil)
// blockchainService defines the interface for interaction with block chain service.
type blockchainService interface {
blockchain.BlockReceiver
blockchain.HeadFetcher
blockchain.FinalizationFetcher
}
// Config to set up the initial sync service.
type Config struct {
P2P p2p.P2P
DB db.ReadOnlyDatabase
Chain blockchainService
StateNotifier statefeed.Notifier
BlockNotifier blockfeed.Notifier
}
// Service service.
type Service struct {
ctx context.Context
cancel context.CancelFunc
chain blockchainService
p2p p2p.P2P
db db.ReadOnlyDatabase
synced *abool.AtomicBool
chainStarted *abool.AtomicBool
stateNotifier statefeed.Notifier
counter *ratecounter.RateCounter
genesisChan chan time.Time
}
// NewService configures the initial sync service responsible for bringing the node up to the
// latest head of the blockchain.
func NewService(ctx context.Context, cfg *Config) *Service {
ctx, cancel := context.WithCancel(ctx)
s := &Service{
ctx: ctx,
cancel: cancel,
chain: cfg.Chain,
p2p: cfg.P2P,
db: cfg.DB,
synced: abool.New(),
chainStarted: abool.New(),
stateNotifier: cfg.StateNotifier,
counter: ratecounter.NewRateCounter(counterSeconds * time.Second),
genesisChan: make(chan time.Time),
}
go s.waitForStateInitialization()
return s
}
// Start the initial sync service.
func (s *Service) Start() {
// Wait for state initialized event.
genesis := <-s.genesisChan
if genesis.IsZero() {
log.Debug("Exiting Initial Sync Service")
return
}
if flags.Get().DisableSync {
s.markSynced(genesis)
log.WithField("genesisTime", genesis).Info("Due to Sync Being Disabled, entering regular sync immediately.")
return
}
if genesis.After(timeutils.Now()) {
s.markSynced(genesis)
log.WithField("genesisTime", genesis).Info("Genesis time has not arrived - not syncing")
return
}
currentSlot := helpers.SlotsSince(genesis)
if helpers.SlotToEpoch(currentSlot) == 0 {
log.WithField("genesisTime", genesis).Info("Chain started within the last epoch - not syncing")
s.markSynced(genesis)
return
}
s.chainStarted.Set()
log.Info("Starting initial chain sync...")
// Are we already in sync, or close to it?
if helpers.SlotToEpoch(s.chain.HeadSlot()) == helpers.SlotToEpoch(currentSlot) {
log.Info("Already synced to the current chain head")
s.markSynced(genesis)
return
}
s.waitForMinimumPeers()
if err := s.roundRobinSync(genesis); err != nil {
if errors.Is(s.ctx.Err(), context.Canceled) {
return
}
panic(err)
}
log.Infof("Synced up to slot %d", s.chain.HeadSlot())
s.markSynced(genesis)
}
// Stop initial sync.
func (s *Service) Stop() error {
s.cancel()
return nil
}
// Status of initial sync.
func (s *Service) Status() error {
if s.synced.IsNotSet() && s.chainStarted.IsSet() {
return errors.New("syncing")
}
return nil
}
// Syncing returns true if initial sync is still running.
func (s *Service) Syncing() bool {
return s.synced.IsNotSet()
}
// Initialized returns true if initial sync has been started.
func (s *Service) Initialized() bool {
return s.chainStarted.IsSet()
}
// Resync allows a node to start syncing again if it has fallen
// behind the current network head.
func (s *Service) Resync() error {
headState, err := s.chain.HeadState(s.ctx)
if err != nil || headState == nil {
return errors.Errorf("could not retrieve head state: %v", err)
}
// Set it to false since we are syncing again.
s.synced.UnSet()
defer func() { s.synced.Set() }() // Reset it at the end of the method.
genesis := time.Unix(int64(headState.GenesisTime()), 0)
s.waitForMinimumPeers()
if err = s.roundRobinSync(genesis); err != nil {
log = log.WithError(err)
}
log.WithField("slot", s.chain.HeadSlot()).Info("Resync attempt complete")
return nil
}
func (s *Service) waitForMinimumPeers() {
required := params.BeaconConfig().MaxPeersToSync
if flags.Get().MinimumSyncPeers < required {
required = flags.Get().MinimumSyncPeers
}
for {
_, peers := s.p2p.Peers().BestNonFinalized(flags.Get().MinimumSyncPeers, s.chain.FinalizedCheckpt().Epoch)
if len(peers) >= required {
break
}
log.WithFields(logrus.Fields{
"suitable": len(peers),
"required": required,
}).Info("Waiting for enough suitable peers before syncing")
time.Sleep(handshakePollingInterval)
}
}
// waitForStateInitialization makes sure that beacon node is ready to be accessed: it is either
// already properly configured or system waits up until state initialized event is triggered.
func (s *Service) waitForStateInitialization() {
// Wait for state to be initialized.
stateChannel := make(chan *feed.Event, 1)
stateSub := s.stateNotifier.StateFeed().Subscribe(stateChannel)
defer stateSub.Unsubscribe()
log.Info("Waiting for state to be initialized")
for {
select {
case event := <-stateChannel:
if event.Type == statefeed.Initialized {
data, ok := event.Data.(*statefeed.InitializedData)
if !ok {
log.Error("Event feed data is not type *statefeed.InitializedData")
continue
}
log.WithField("starttime", data.StartTime).Debug("Received state initialized event")
s.genesisChan <- data.StartTime
return
}
case <-s.ctx.Done():
log.Debug("Context closed, exiting goroutine")
// Send a zero time in the event we are exiting.
s.genesisChan <- time.Time{}
return
case err := <-stateSub.Err():
log.WithError(err).Error("Subscription to state notifier failed")
// Send a zero time in the event we are exiting.
s.genesisChan <- time.Time{}
return
}
}
}
// markSynced marks node as synced and notifies feed listeners.
func (s *Service) markSynced(genesis time.Time) {
s.synced.Set()
s.stateNotifier.StateFeed().Send(&feed.Event{
Type: statefeed.Synced,
Data: &statefeed.SyncedData{
StartTime: genesis,
},
})
}