1  package libp2p
 2  
 3  import (
 4  	"context"
 5  	"time"
 6  
 7  	"github.com/libp2p/go-libp2p/core/host"
 8  	"github.com/libp2p/go-libp2p/core/peer"
 9  	"github.com/libp2p/go-libp2p/p2p/discovery/mdns"
10  
11  	"go.uber.org/fx"
12  
13  	"github.com/ipfs/kubo/core/node/helpers"
14  )
15  
16  const discoveryConnTimeout = time.Second * 30
17  
18  type discoveryHandler struct {
19  	ctx  context.Context
20  	host host.Host
21  }
22  
23  func (dh *discoveryHandler) HandlePeerFound(p peer.AddrInfo) {
24  	log.Info("connecting to discovered peer: ", p)
25  	ctx, cancel := context.WithTimeout(dh.ctx, discoveryConnTimeout)
26  	defer cancel()
27  	if err := dh.host.Connect(ctx, p); err != nil {
28  		log.Warnf("failed to connect to peer %s found by discovery: %s", p.ID, err)
29  	}
30  }
31  
32  func DiscoveryHandler(mctx helpers.MetricsCtx, lc fx.Lifecycle, host host.Host) *discoveryHandler {
33  	return &discoveryHandler{
34  		ctx:  helpers.LifecycleCtx(mctx, lc),
35  		host: host,
36  	}
37  }
38  
39  func SetupDiscovery(useMdns bool) func(helpers.MetricsCtx, fx.Lifecycle, host.Host, *discoveryHandler) error {
40  	return func(mctx helpers.MetricsCtx, lc fx.Lifecycle, host host.Host, handler *discoveryHandler) error {
41  		if useMdns {
42  			service := mdns.NewMdnsService(host, mdns.ServiceName, handler)
43  			if err := service.Start(); err != nil {
44  				log.Error("error starting mdns service: ", err)
45  				return nil
46  			}
47  		}
48  		return nil
49  	}
50  }