86 lines
2.0 KiB
Go
86 lines
2.0 KiB
Go
|
package discovery
|
||
|
|
|
||
|
|
import (
|
||
|
|
"context"
|
||
|
|
"time"
|
||
|
|
|
||
|
|
cid "github.com/ipfs/go-cid"
|
||
|
|
|
||
|
|
"github.com/libp2p/go-libp2p-core/peer"
|
||
|
|
"github.com/libp2p/go-libp2p-core/routing"
|
||
|
|
|
||
|
|
mh "github.com/multiformats/go-multihash"
|
||
|
|
)
|
||
|
|
|
||
|
|
// RoutingDiscovery is an implementation of discovery using ContentRouting
|
||
|
|
// Namespaces are translated to Cids using the SHA256 hash.
|
||
|
|
type RoutingDiscovery struct {
|
||
|
|
routing.ContentRouting
|
||
|
|
}
|
||
|
|
|
||
|
|
func NewRoutingDiscovery(router routing.ContentRouting) *RoutingDiscovery {
|
||
|
|
return &RoutingDiscovery{router}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (d *RoutingDiscovery) Advertise(ctx context.Context, ns string, opts ...Option) (time.Duration, error) {
|
||
|
|
var options Options
|
||
|
|
err := options.Apply(opts...)
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
|
||
|
|
ttl := options.Ttl
|
||
|
|
if ttl == 0 || ttl > 3*time.Hour {
|
||
|
|
// the DHT provider record validity is 24hrs, but it is recommnded to republish at least every 6hrs
|
||
|
|
// we go one step further and republish every 3hrs
|
||
|
|
ttl = 3 * time.Hour
|
||
|
|
}
|
||
|
|
|
||
|
|
cid, err := nsToCid(ns)
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
|
||
|
|
// this context requires a timeout; it determines how long the DHT looks for
|
||
|
|
// closest peers to the key/CID before it goes on to provide the record to them.
|
||
|
|
// Not setting a timeout here will make the DHT wander forever.
|
||
|
|
pctx, cancel := context.WithTimeout(ctx, 60*time.Second)
|
||
|
|
defer cancel()
|
||
|
|
|
||
|
|
err = d.Provide(pctx, cid, true)
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
|
||
|
|
return ttl, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (d *RoutingDiscovery) FindPeers(ctx context.Context, ns string, opts ...Option) (<-chan peer.AddrInfo, error) {
|
||
|
|
var options Options
|
||
|
|
err := options.Apply(opts...)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
|
||
|
|
limit := options.Limit
|
||
|
|
if limit == 0 {
|
||
|
|
limit = 100 // that's just arbitrary, but FindProvidersAsync needs a count
|
||
|
|
}
|
||
|
|
|
||
|
|
cid, err := nsToCid(ns)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
|
||
|
|
return d.FindProvidersAsync(ctx, cid, limit), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func nsToCid(ns string) (cid.Cid, error) {
|
||
|
|
h, err := mh.Sum([]byte(ns), mh.SHA2_256, -1)
|
||
|
|
if err != nil {
|
||
|
|
return cid.Undef, err
|
||
|
|
}
|
||
|
|
|
||
|
|
return cid.NewCidV1(cid.Raw, h), nil
|
||
|
|
}
|