// Kademlia 'node lookup' operation. Returns a channel of the K closest peers
// to the given key
func (dht *IpfsDHT) GetClosestPeers(ctx context.Context, key key.Key) (<-chan peer.ID, error) {
e := log.EventBegin(ctx, "getClosestPeers", &key)
tablepeers := dht.routingTable.NearestPeers(kb.ConvertKey(key), KValue)
if len(tablepeers) == 0 {
return nil, kb.ErrLookupFailure
}
out := make(chan peer.ID, KValue)
peerset := pset.NewLimited(KValue)
for _, p := range tablepeers {
select {
case out <- p:
case <-ctx.Done():
return nil, ctx.Err()
}
peerset.Add(p)
}
// since the query doesnt actually pass our context down
// we have to hack this here. whyrusleeping isnt a huge fan of goprocess
parent := ctx
query := dht.newQuery(key, func(ctx context.Context, p peer.ID) (*dhtQueryResult, error) {
// For DHT query command
notif.PublishQueryEvent(parent, ¬if.QueryEvent{
Type: notif.SendingQuery,
ID: p,
})
closer, err := dht.closerPeersSingle(ctx, key, p)
if err != nil {
log.Debugf("error getting closer peers: %s", err)
return nil, err
}
var filtered []peer.PeerInfo
for _, clp := range closer {
if kb.Closer(clp, dht.self, key) && peerset.TryAdd(clp) {
select {
case out <- clp:
case <-ctx.Done():
return nil, ctx.Err()
}
filtered = append(filtered, dht.peerstore.PeerInfo(clp))
}
}
// For DHT query command
notif.PublishQueryEvent(parent, ¬if.QueryEvent{
Type: notif.PeerResponse,
ID: p,
Responses: pointerizePeerInfos(filtered),
})
return &dhtQueryResult{closerPeers: filtered}, nil
})
go func() {
defer close(out)
defer e.Done()
// run it!
_, err := query.Run(ctx, tablepeers)
if err != nil {
log.Debugf("closestPeers query run error: %s", err)
}
}()
return out, nil
}
func (dht *IpfsDHT) findProvidersAsyncRoutine(ctx context.Context, key key.Key, count int, peerOut chan peer.PeerInfo) {
defer log.EventBegin(ctx, "findProvidersAsync", &key).Done()
defer close(peerOut)
ps := pset.NewLimited(count)
provs := dht.providers.GetProviders(ctx, key)
for _, p := range provs {
// NOTE: assuming that this list of peers is unique
if ps.TryAdd(p) {
select {
case peerOut <- dht.peerstore.PeerInfo(p):
case <-ctx.Done():
return
}
}
// If we have enough peers locally, dont bother with remote RPC
if ps.Size() >= count {
return
}
}
// setup the Query
parent := ctx
query := dht.newQuery(key, func(ctx context.Context, p peer.ID) (*dhtQueryResult, error) {
notif.PublishQueryEvent(parent, ¬if.QueryEvent{
Type: notif.SendingQuery,
ID: p,
})
pmes, err := dht.findProvidersSingle(ctx, p, key)
if err != nil {
return nil, err
}
log.Debugf("%d provider entries", len(pmes.GetProviderPeers()))
provs := pb.PBPeersToPeerInfos(pmes.GetProviderPeers())
log.Debugf("%d provider entries decoded", len(provs))
// Add unique providers from request, up to 'count'
for _, prov := range provs {
log.Debugf("got provider: %s", prov)
if ps.TryAdd(prov.ID) {
log.Debugf("using provider: %s", prov)
select {
case peerOut <- prov:
case <-ctx.Done():
log.Debug("Context timed out sending more providers")
return nil, ctx.Err()
}
}
if ps.Size() >= count {
log.Debugf("got enough providers (%d/%d)", ps.Size(), count)
return &dhtQueryResult{success: true}, nil
}
}
// Give closer peers back to the query to be queried
closer := pmes.GetCloserPeers()
clpeers := pb.PBPeersToPeerInfos(closer)
log.Debugf("got closer peers: %d %s", len(clpeers), clpeers)
notif.PublishQueryEvent(parent, ¬if.QueryEvent{
Type: notif.PeerResponse,
ID: p,
Responses: pointerizePeerInfos(clpeers),
})
return &dhtQueryResult{closerPeers: clpeers}, nil
})
peers := dht.routingTable.NearestPeers(kb.ConvertKey(key), KValue)
_, err := query.Run(ctx, peers)
if err != nil {
log.Debugf("Query error: %s", err)
notif.PublishQueryEvent(ctx, ¬if.QueryEvent{
Type: notif.QueryError,
Extra: err.Error(),
})
}
}