// GetValue searches for the value corresponding to given Key.
// If the search does not succeed, a multiaddr string of a closer peer is
// returned along with util.ErrSearchIncomplete
func (dht *IpfsDHT) GetValue(ctx context.Context, key key.Key) ([]byte, error) {
// If we have it local, dont bother doing an RPC!
val, err := dht.getLocal(key)
if err == nil {
log.Debug("have it locally")
return val, nil
} else {
log.Debug("failed to get value locally: %s", err)
}
// get closest peers in the routing table
rtp := dht.routingTable.NearestPeers(kb.ConvertKey(key), AlphaValue)
log.Debugf("peers in rt: %s", len(rtp), rtp)
if len(rtp) == 0 {
log.Warning("No peers from routing table!")
return nil, kb.ErrLookupFailure
}
// 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,
})
val, peers, err := dht.getValueOrPeers(ctx, p, key)
if err != nil {
return nil, err
}
res := &dhtQueryResult{value: val, closerPeers: peers}
if val != nil {
res.success = true
}
notif.PublishQueryEvent(parent, ¬if.QueryEvent{
Type: notif.PeerResponse,
ID: p,
Responses: pointerizePeerInfos(peers),
})
return res, nil
})
// run it!
result, err := query.Run(ctx, rtp)
if err != nil {
return nil, err
}
log.Debugf("GetValue %v %v", key, result.value)
if result.value == nil {
return nil, routing.ErrNotFound
}
return result.value, nil
}
// PingRoutine periodically pings nearest neighbors.
func (dht *IpfsDHT) PingRoutine(t time.Duration) {
defer dht.Children().Done()
tick := time.Tick(t)
for {
select {
case <-tick:
id := make([]byte, 16)
rand.Read(id)
peers := dht.routingTable.NearestPeers(kb.ConvertKey(key.Key(id)), 5)
for _, p := range peers {
ctx, cancel := context.WithTimeout(dht.Context(), time.Second*5)
_, err := dht.Ping(ctx, p)
if err != nil {
log.Debugf("Ping error: %s", err)
}
cancel()
}
case <-dht.Closing():
return
}
}
}
func sortedByKey(peers []peer.ID, skey string) []peer.ID {
target := kbucket.ConvertKey(key.Key(skey))
return kbucket.SortClosestPeers(peers, target)
}
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), AlphaValue)
_, 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(),
})
}
}
// nearestPeersToQuery returns the routing tables closest peers.
func (dht *IpfsDHT) nearestPeersToQuery(pmes *pb.Message, count int) []peer.ID {
key := key.Key(pmes.GetKey())
closer := dht.routingTable.NearestPeers(kb.ConvertKey(key), count)
return closer
}
func (dht *IpfsDHT) GetValues(ctx context.Context, key key.Key, nvals int) ([]routing.RecvdVal, error) {
var vals []routing.RecvdVal
var valslock sync.Mutex
// If we have it local, dont bother doing an RPC!
lrec, err := dht.getLocal(key)
if err == nil {
// TODO: this is tricky, we dont always want to trust our own value
// what if the authoritative source updated it?
log.Debug("have it locally")
vals = append(vals, routing.RecvdVal{
Val: lrec.GetValue(),
From: dht.self,
})
if nvals <= 1 {
return vals, nil
}
} else if nvals == 0 {
return nil, err
}
// get closest peers in the routing table
rtp := dht.routingTable.NearestPeers(kb.ConvertKey(key), KValue)
log.Debugf("peers in rt: %s", len(rtp), rtp)
if len(rtp) == 0 {
log.Warning("No peers from routing table!")
return nil, kb.ErrLookupFailure
}
// 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,
})
rec, peers, err := dht.getValueOrPeers(ctx, p, key)
switch err {
case routing.ErrNotFound:
// in this case, they responded with nothing,
// still send a notification so listeners can know the
// request has completed 'successfully'
notif.PublishQueryEvent(parent, ¬if.QueryEvent{
Type: notif.PeerResponse,
ID: p,
})
return nil, err
default:
return nil, err
case nil, errInvalidRecord:
// in either of these cases, we want to keep going
}
res := &dhtQueryResult{closerPeers: peers}
if rec.GetValue() != nil || err == errInvalidRecord {
rv := routing.RecvdVal{
Val: rec.GetValue(),
From: p,
}
valslock.Lock()
vals = append(vals, rv)
// If weve collected enough records, we're done
if len(vals) >= nvals {
res.success = true
}
valslock.Unlock()
}
notif.PublishQueryEvent(parent, ¬if.QueryEvent{
Type: notif.PeerResponse,
ID: p,
Responses: pointerizePeerInfos(peers),
})
return res, nil
})
// run it!
_, err = query.Run(ctx, rtp)
if len(vals) == 0 {
if err != nil {
return nil, err
}
}
return vals, nil
}
// 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
}