Example with mdns discovery

[deckbsd]

Hello everybody,

I'm working on sample of how to use mDNS to find other peers. And well it didn't work very much. I don't know what i'm doing wrong. I'have followed some guidelines from here or here i'm kind of new in network programming, but i really want to know how it works because i think that what you are doing with p2plib , ipfs and so on is really great. here is my code :

package main

import (
	"context"
	"fmt"
	"time"

	crypto "github.com/libp2p/go-libp2p-crypto"
	peer "github.com/libp2p/go-libp2p-peer"
	bhost "github.com/libp2p/go-libp2p/p2p/host/basic"

	host "github.com/libp2p/go-libp2p-host"

	pstore "github.com/libp2p/go-libp2p-peerstore"
	swarm "github.com/libp2p/go-libp2p-swarm"
	disco "github.com/libp2p/go-libp2p/p2p/discovery"
	ma "github.com/multiformats/go-multiaddr"
)

type DiscoveryNotifee struct {
	h host.Host
}

func (n *DiscoveryNotifee) HandlePeerFound(pi pstore.PeerInfo) {
	fmt.Printf("discovered :")
	fmt.Println(pi)
}

func makeRandomNode(port int, ctx context.Context) *bhost.BasicHost {
	// Ignoring most errors for brevity
	// See echo example for more details and better implementation
	priv, pub, _ := crypto.GenerateKeyPair(crypto.Secp256k1, 256)
	pid, _ := peer.IDFromPublicKey(pub)
	listen, _ := ma.NewMultiaddr(fmt.Sprintf("/ip4/127.0.0.1/tcp/%d", port))
	peerStore := pstore.NewPeerstore()
	peerStore.AddPrivKey(pid, priv)
	peerStore.AddPubKey(pid, pub)
	n, _ := swarm.NewNetwork(ctx, []ma.Multiaddr{listen}, pid, peerStore, nil)
	host := bhost.New(n)

	fmt.Println(host)
	return host
}

func main() {

	ctxa := context.Background()
	ctxb := context.Background()

	a := makeRandomNode(9000, ctxa)
	b := makeRandomNode(9001, ctxb)

	peersNode1 := len(a.Peerstore().Peers())
	peersNode2 := len(b.Peerstore().Peers())

	_ = peersNode1
	_ = peersNode2

	sa, err := disco.NewMdnsService(ctxa, a, time.Second/4, "findme")
	if err != nil {
		panic(err)
	}

	sb, err := disco.NewMdnsService(ctxb, b, time.Second/4, "findme")
	if err != nil {
		panic(err)
	}

	_ = sb

	n := &DiscoveryNotifee{a}

	sa.RegisterNotifee(n)

	time.Sleep(time.Second * 10)

	peersNodea := len(a.Peerstore().Peers())
	peersNodeb := len(b.Peerstore().Peers())

	_ = peersNodea
	_ = peersNodeb

	err = a.Connect(context.Background(), pstore.PeerInfo{ID: b.ID()})
	if err != nil {
		panic(err)
	}
}

do i need a routed host or something ? i'm a little bit confuse. Sorry for boring you probably with my little problem :-)

Edit : I just saw #257, maybe it's linked if nobody found nothing wrong in my code ? I 'll have a look at zeroconf and i ll try to implement it in discovery instead of mdns from whyrusleeping, but again, i'm a very newbie in that domain :-) and in golang too.

[deckbsd]

Actually, i tested the zeroconf library, it works really well. So i'm would like to replace it, in case if nobody did it during this time is there a doc to learn how to upload code on this project ? (i'm ok with git practise , but not in open-source oriented project).

[Stebalien]

There's ongoing work here: #285

[deckbsd]

Hi @Stebalien , yep i saw that already, that's why i didn't talk more about it. i'll flag it as resolved. thanks 👍