Convert mDNS to DHT

0xfederama · May 5, 2021, 12:44pm

Hi everyone, I’m doing a simulation of a super simple bitcoin-like protocol on a GossipSub network (and it also uses direct messaging with a stream handler for some messages).
I made everything following this example (go-libp2p-examples/pubsub/chat at master · libp2p/go-libp2p-examples · GitHub) with mDNS for peer routing and discovery, but now I need to use DHT discovery to use the protocol outside LAN.
This is my code (GitHub - 0xfederama/bitcoin-simulation-libp2p: Simple Bitcoin protocol simulation using Go and Libp2p). How can I modify my routing system to use DHT instead of mDNS?

hector · May 5, 2021, 2:26pm

You’d need to set the DHT when creating the libp2p node, and make sure you connect to some bootstrappers on boot.

An example:

github.com

hsanjuan/ipfs-lite/blob/master/util.go#L81-L84


		libp2p.Routing(func(h host.Host) (routing.PeerRouting, error) {
			ddht, err = newDHT(ctx, h, ds)
			return ddht, err
		}),

github.com

hsanjuan/ipfs-lite/blob/master/ipfs.go#L200


	<-p.ctx.Done()
	p.reprovider.Close()
	p.bserv.Close()
}


// Bootstrap is an optional helper to connect to the given peers and bootstrap
// the Peer DHT (and Bitswap). This is a best-effort function. Errors are only
// logged and a warning is printed when less than half of the given peers
// could be contacted. It is fine to pass a list where some peers will not be
// reachable.
func (p *Peer) Bootstrap(peers []peer.AddrInfo) {
	connected := make(chan struct{})


	var wg sync.WaitGroup
	for _, pinfo := range peers {
		//h.Peerstore().AddAddrs(pinfo.ID, pinfo.Addrs, peerstore.PermanentAddrTTL)
		wg.Add(1)
		go func(pinfo peer.AddrInfo) {
			defer wg.Done()
			err := p.host.Connect(p.ctx, pinfo)
			if err != nil {

0xfederama · May 6, 2021, 2:07pm

@hector I modified it (GitHub - 0xfederama/bitcoin-simulation-libp2p at mdns-to-dht), but it doesn’t work properly. I tried running the cose with two peers. At line 78 I print every new peer that I find, and I can see that it prints the other peer’s ID. But then it seems like every peer connects to a different GossipSub network, because at line 119 it prints 0 peers and one peer cannot receive the other peer’s message.

Could you please help me to resolve this? I can’t find a fix

hector · May 7, 2021, 8:50pm

I had a quick look on master and I am not sure why peers would not receive the messages. Things seem ok.

0xfederama · May 7, 2021, 10:14pm

Now I fixed it, it works. Thanks for your help <3

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Convert mDNS to DHT

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