lotus/chain/blocksync/blocksync_client.go
2020-06-23 18:51:25 -03:00

603 lines
15 KiB
Go

package blocksync
import (
"bufio"
"context"
"fmt"
"math/rand"
"sort"
"sync"
"time"
blocks "github.com/ipfs/go-block-format"
bserv "github.com/ipfs/go-blockservice"
"github.com/ipfs/go-cid"
graphsync "github.com/ipfs/go-graphsync"
gsnet "github.com/ipfs/go-graphsync/network"
host "github.com/libp2p/go-libp2p-core/host"
inet "github.com/libp2p/go-libp2p-core/network"
"github.com/libp2p/go-libp2p-core/peer"
"go.opencensus.io/trace"
"golang.org/x/xerrors"
cborutil "github.com/filecoin-project/go-cbor-util"
"github.com/filecoin-project/lotus/chain/store"
"github.com/filecoin-project/lotus/chain/types"
incrt "github.com/filecoin-project/lotus/lib/increadtimeout"
"github.com/filecoin-project/lotus/lib/peermgr"
"github.com/filecoin-project/lotus/node/modules/dtypes"
)
type BlockSync struct {
bserv bserv.BlockService
gsync graphsync.GraphExchange
host host.Host
syncPeers *bsPeerTracker
peerMgr *peermgr.PeerMgr
}
func NewBlockSyncClient(bserv dtypes.ChainBlockService, h host.Host, pmgr peermgr.MaybePeerMgr, gs dtypes.Graphsync) *BlockSync {
return &BlockSync{
bserv: bserv,
host: h,
syncPeers: newPeerTracker(pmgr.Mgr),
peerMgr: pmgr.Mgr,
gsync: gs,
}
}
func (bs *BlockSync) processStatus(req *BlockSyncRequest, res *BlockSyncResponse) error {
switch res.Status {
case StatusPartial: // Partial Response
return xerrors.Errorf("not handling partial blocksync responses yet")
case StatusNotFound: // req.Start not found
return xerrors.Errorf("not found")
case StatusGoAway: // Go Away
return xerrors.Errorf("not handling 'go away' blocksync responses yet")
case StatusInternalError: // Internal Error
return xerrors.Errorf("block sync peer errored: %s", res.Message)
case StatusBadRequest:
return xerrors.Errorf("block sync request invalid: %s", res.Message)
default:
return xerrors.Errorf("unrecognized response code: %d", res.Status)
}
}
// GetBlocks fetches count blocks from the network, from the provided tipset
// *backwards*, returning as many tipsets as count.
//
// {hint/usage}: This is used by the Syncer during normal chain syncing and when
// resolving forks.
func (bs *BlockSync) GetBlocks(ctx context.Context, tsk types.TipSetKey, count int) ([]*types.TipSet, error) {
ctx, span := trace.StartSpan(ctx, "bsync.GetBlocks")
defer span.End()
if span.IsRecordingEvents() {
span.AddAttributes(
trace.StringAttribute("tipset", fmt.Sprint(tsk.Cids())),
trace.Int64Attribute("count", int64(count)),
)
}
req := &BlockSyncRequest{
Start: tsk.Cids(),
RequestLength: uint64(count),
Options: BSOptBlocks,
}
// this peerset is sorted by latency and failure counting.
peers := bs.getPeers()
// randomize the first few peers so we don't always pick the same peer
shufflePrefix(peers)
start := time.Now()
var oerr error
for _, p := range peers {
// TODO: doing this synchronously isnt great, but fetching in parallel
// may not be a good idea either. think about this more
select {
case <-ctx.Done():
return nil, xerrors.Errorf("blocksync getblocks failed: %w", ctx.Err())
default:
}
res, err := bs.sendRequestToPeer(ctx, p, req)
if err != nil {
oerr = err
if !xerrors.Is(err, inet.ErrNoConn) {
log.Warnf("BlockSync request failed for peer %s: %s", p.String(), err)
}
continue
}
if res.Status == StatusOK || res.Status == StatusPartial {
resp, err := bs.processBlocksResponse(req, res)
if err != nil {
return nil, xerrors.Errorf("success response from peer failed to process: %w", err)
}
bs.syncPeers.logGlobalSuccess(time.Since(start))
bs.host.ConnManager().TagPeer(p, "bsync", 25)
return resp, nil
}
oerr = bs.processStatus(req, res)
if oerr != nil {
log.Warnf("BlockSync peer %s response was an error: %s", p.String(), oerr)
}
}
return nil, xerrors.Errorf("GetBlocks failed with all peers: %w", oerr)
}
func (bs *BlockSync) GetFullTipSet(ctx context.Context, p peer.ID, tsk types.TipSetKey) (*store.FullTipSet, error) {
// TODO: round robin through these peers on error
req := &BlockSyncRequest{
Start: tsk.Cids(),
RequestLength: 1,
Options: BSOptBlocks | BSOptMessages,
}
res, err := bs.sendRequestToPeer(ctx, p, req)
if err != nil {
return nil, err
}
switch res.Status {
case 0: // Success
if len(res.Chain) == 0 {
return nil, fmt.Errorf("got zero length chain response")
}
bts := res.Chain[0]
return bstsToFullTipSet(bts)
case 101: // Partial Response
return nil, xerrors.Errorf("partial responses are not handled for single tipset fetching")
case 201: // req.Start not found
return nil, fmt.Errorf("not found")
case 202: // Go Away
return nil, xerrors.Errorf("received 'go away' response peer")
case 203: // Internal Error
return nil, fmt.Errorf("block sync peer errored: %q", res.Message)
case 204: // Invalid Request
return nil, fmt.Errorf("block sync request invalid: %q", res.Message)
default:
return nil, fmt.Errorf("unrecognized response code")
}
}
func shufflePrefix(peers []peer.ID) {
pref := 5
if len(peers) < pref {
pref = len(peers)
}
buf := make([]peer.ID, pref)
perm := rand.Perm(pref)
for i, v := range perm {
buf[i] = peers[v]
}
copy(peers, buf)
}
func (bs *BlockSync) GetChainMessages(ctx context.Context, h *types.TipSet, count uint64) ([]*BSTipSet, error) {
ctx, span := trace.StartSpan(ctx, "GetChainMessages")
defer span.End()
peers := bs.getPeers()
// randomize the first few peers so we don't always pick the same peer
shufflePrefix(peers)
req := &BlockSyncRequest{
Start: h.Cids(),
RequestLength: count,
Options: BSOptMessages,
}
var err error
start := time.Now()
for _, p := range peers {
res, rerr := bs.sendRequestToPeer(ctx, p, req)
if rerr != nil {
err = rerr
log.Warnf("BlockSync request failed for peer %s: %s", p.String(), err)
continue
}
if res.Status == StatusOK {
bs.syncPeers.logGlobalSuccess(time.Since(start))
return res.Chain, nil
}
if res.Status == StatusPartial {
// TODO: track partial response sizes to ensure we don't overrequest too often
return res.Chain, nil
}
err = bs.processStatus(req, res)
if err != nil {
log.Warnf("BlockSync peer %s response was an error: %s", p.String(), err)
}
}
if err == nil {
return nil, xerrors.Errorf("GetChainMessages failed, no peers connected")
}
// TODO: What if we have no peers (and err is nil)?
return nil, xerrors.Errorf("GetChainMessages failed with all peers(%d): %w", len(peers), err)
}
func (bs *BlockSync) sendRequestToPeer(ctx context.Context, p peer.ID, req *BlockSyncRequest) (_ *BlockSyncResponse, err error) {
ctx, span := trace.StartSpan(ctx, "sendRequestToPeer")
defer span.End()
defer func() {
if err != nil {
if span.IsRecordingEvents() {
span.SetStatus(trace.Status{
Code: 5,
Message: err.Error(),
})
}
}
}()
if span.IsRecordingEvents() {
span.AddAttributes(
trace.StringAttribute("peer", p.Pretty()),
)
}
gsproto := string(gsnet.ProtocolGraphsync)
supp, err := bs.host.Peerstore().SupportsProtocols(p, BlockSyncProtocolID, gsproto)
if err != nil {
return nil, xerrors.Errorf("failed to get protocols for peer: %w", err)
}
if len(supp) == 0 {
return nil, xerrors.Errorf("peer %s supports no known sync protocols", p)
}
switch supp[0] {
case BlockSyncProtocolID:
res, err := bs.fetchBlocksBlockSync(ctx, p, req)
if err != nil {
return nil, xerrors.Errorf("blocksync req failed: %w", err)
}
return res, nil
case gsproto:
res, err := bs.fetchBlocksGraphSync(ctx, p, req)
if err != nil {
return nil, xerrors.Errorf("graphsync req failed: %w", err)
}
return res, nil
default:
return nil, xerrors.Errorf("peerstore somehow returned unexpected protocols: %v", supp)
}
}
func (bs *BlockSync) fetchBlocksBlockSync(ctx context.Context, p peer.ID, req *BlockSyncRequest) (*BlockSyncResponse, error) {
ctx, span := trace.StartSpan(ctx, "blockSyncFetch")
defer span.End()
start := time.Now()
s, err := bs.host.NewStream(inet.WithNoDial(ctx, "should already have connection"), p, BlockSyncProtocolID)
if err != nil {
bs.RemovePeer(p)
return nil, xerrors.Errorf("failed to open stream to peer: %w", err)
}
_ = s.SetWriteDeadline(time.Now().Add(5 * time.Second))
if err := cborutil.WriteCborRPC(s, req); err != nil {
_ = s.SetWriteDeadline(time.Time{})
bs.syncPeers.logFailure(p, time.Since(start))
return nil, err
}
_ = s.SetWriteDeadline(time.Time{})
var res BlockSyncResponse
r := incrt.New(s, 50<<10, 5*time.Second)
if err := cborutil.ReadCborRPC(bufio.NewReader(r), &res); err != nil {
bs.syncPeers.logFailure(p, time.Since(start))
return nil, err
}
if span.IsRecordingEvents() {
span.AddAttributes(
trace.Int64Attribute("resp_status", int64(res.Status)),
trace.StringAttribute("msg", res.Message),
trace.Int64Attribute("chain_len", int64(len(res.Chain))),
)
}
bs.syncPeers.logSuccess(p, time.Since(start))
return &res, nil
}
func (bs *BlockSync) processBlocksResponse(req *BlockSyncRequest, res *BlockSyncResponse) ([]*types.TipSet, error) {
if len(res.Chain) == 0 {
return nil, xerrors.Errorf("got no blocks in successful blocksync response")
}
cur, err := types.NewTipSet(res.Chain[0].Blocks)
if err != nil {
return nil, err
}
out := []*types.TipSet{cur}
for bi := 1; bi < len(res.Chain); bi++ {
next := res.Chain[bi].Blocks
nts, err := types.NewTipSet(next)
if err != nil {
return nil, err
}
if !types.CidArrsEqual(cur.Parents().Cids(), nts.Cids()) {
return nil, fmt.Errorf("parents of tipset[%d] were not tipset[%d]", bi-1, bi)
}
out = append(out, nts)
cur = nts
}
return out, nil
}
func (bs *BlockSync) GetBlock(ctx context.Context, c cid.Cid) (*types.BlockHeader, error) {
sb, err := bs.bserv.GetBlock(ctx, c)
if err != nil {
return nil, err
}
return types.DecodeBlock(sb.RawData())
}
func (bs *BlockSync) AddPeer(p peer.ID) {
bs.syncPeers.addPeer(p)
}
func (bs *BlockSync) RemovePeer(p peer.ID) {
bs.syncPeers.removePeer(p)
}
// getPeers returns a preference-sorted set of peers to query.
func (bs *BlockSync) getPeers() []peer.ID {
return bs.syncPeers.prefSortedPeers()
}
func (bs *BlockSync) FetchMessagesByCids(ctx context.Context, cids []cid.Cid) ([]*types.Message, error) {
out := make([]*types.Message, len(cids))
err := bs.fetchCids(ctx, cids, func(i int, b blocks.Block) error {
msg, err := types.DecodeMessage(b.RawData())
if err != nil {
return err
}
if out[i] != nil {
return fmt.Errorf("received duplicate message")
}
out[i] = msg
return nil
})
if err != nil {
return nil, err
}
return out, nil
}
func (bs *BlockSync) FetchSignedMessagesByCids(ctx context.Context, cids []cid.Cid) ([]*types.SignedMessage, error) {
out := make([]*types.SignedMessage, len(cids))
err := bs.fetchCids(ctx, cids, func(i int, b blocks.Block) error {
smsg, err := types.DecodeSignedMessage(b.RawData())
if err != nil {
return err
}
if out[i] != nil {
return fmt.Errorf("received duplicate message")
}
out[i] = smsg
return nil
})
if err != nil {
return nil, err
}
return out, nil
}
func (bs *BlockSync) fetchCids(ctx context.Context, cids []cid.Cid, cb func(int, blocks.Block) error) error {
resp := bs.bserv.GetBlocks(context.TODO(), cids)
m := make(map[cid.Cid]int)
for i, c := range cids {
m[c] = i
}
for i := 0; i < len(cids); i++ {
select {
case v, ok := <-resp:
if !ok {
if i == len(cids)-1 {
break
}
return fmt.Errorf("failed to fetch all messages")
}
ix, ok := m[v.Cid()]
if !ok {
return fmt.Errorf("received message we didnt ask for")
}
if err := cb(ix, v); err != nil {
return err
}
}
}
return nil
}
type peerStats struct {
successes int
failures int
firstSeen time.Time
averageTime time.Duration
}
type bsPeerTracker struct {
lk sync.Mutex
peers map[peer.ID]*peerStats
avgGlobalTime time.Duration
pmgr *peermgr.PeerMgr
}
func newPeerTracker(pmgr *peermgr.PeerMgr) *bsPeerTracker {
return &bsPeerTracker{
peers: make(map[peer.ID]*peerStats),
pmgr: pmgr,
}
}
func (bpt *bsPeerTracker) addPeer(p peer.ID) {
bpt.lk.Lock()
defer bpt.lk.Unlock()
if _, ok := bpt.peers[p]; ok {
return
}
bpt.peers[p] = &peerStats{
firstSeen: time.Now(),
}
}
const (
// newPeerMul is how much better than average is the new peer assumed to be
// less than one to encourouge trying new peers
newPeerMul = 0.9
)
func (bpt *bsPeerTracker) prefSortedPeers() []peer.ID {
// TODO: this could probably be cached, but as long as its not too many peers, fine for now
bpt.lk.Lock()
defer bpt.lk.Unlock()
out := make([]peer.ID, 0, len(bpt.peers))
for p := range bpt.peers {
out = append(out, p)
}
// sort by 'expected cost' of requesting data from that peer
// additionally handle edge cases where not enough data is available
sort.Slice(out, func(i, j int) bool {
pi := bpt.peers[out[i]]
pj := bpt.peers[out[j]]
var costI, costJ float64
getPeerInitLat := func(p peer.ID) float64 {
var res float64
if bpt.pmgr != nil {
if lat, ok := bpt.pmgr.GetPeerLatency(p); ok {
res = float64(lat)
}
}
if res == 0 {
res = float64(bpt.avgGlobalTime)
}
return res * newPeerMul
}
if pi.successes+pi.failures > 0 {
failRateI := float64(pi.failures) / float64(pi.failures+pi.successes)
costI = float64(pi.averageTime) + failRateI*float64(bpt.avgGlobalTime)
} else {
costI = getPeerInitLat(out[i])
}
if pj.successes+pj.failures > 0 {
failRateJ := float64(pj.failures) / float64(pj.failures+pj.successes)
costJ = float64(pj.averageTime) + failRateJ*float64(bpt.avgGlobalTime)
} else {
costJ = getPeerInitLat(out[j])
}
return costI < costJ
})
return out
}
const (
// xInvAlpha = (N+1)/2
localInvAlpha = 5 // 86% of the value is the last 9
globalInvAlpha = 20 // 86% of the value is the last 39
)
func (bpt *bsPeerTracker) logGlobalSuccess(dur time.Duration) {
bpt.lk.Lock()
defer bpt.lk.Unlock()
if bpt.avgGlobalTime == 0 {
bpt.avgGlobalTime = dur
return
}
delta := (dur - bpt.avgGlobalTime) / globalInvAlpha
bpt.avgGlobalTime += delta
}
func logTime(pi *peerStats, dur time.Duration) {
if pi.averageTime == 0 {
pi.averageTime = dur
return
}
delta := (dur - pi.averageTime) / localInvAlpha
pi.averageTime += delta
}
func (bpt *bsPeerTracker) logSuccess(p peer.ID, dur time.Duration) {
bpt.lk.Lock()
defer bpt.lk.Unlock()
var pi *peerStats
var ok bool
if pi, ok = bpt.peers[p]; !ok {
log.Warnw("log success called on peer not in tracker", "peerid", p.String())
return
}
pi.successes++
logTime(pi, dur)
}
func (bpt *bsPeerTracker) logFailure(p peer.ID, dur time.Duration) {
bpt.lk.Lock()
defer bpt.lk.Unlock()
var pi *peerStats
var ok bool
if pi, ok = bpt.peers[p]; !ok {
log.Warn("log failure called on peer not in tracker", "peerid", p.String())
return
}
pi.failures++
logTime(pi, dur)
}
func (bpt *bsPeerTracker) removePeer(p peer.ID) {
bpt.lk.Lock()
defer bpt.lk.Unlock()
delete(bpt.peers, p)
}