Fix "no protocol with name dnsaddr" error

[avbasov]

No description provided.

[anacrolix]

Thanks for the patch. Could you provide a little context on when you're seeing this error?

[avbasov]

It's because of that new DefaultBootstrapPeers variable, which is initialised into the init function.
go-multiaddr module doesn't support a "dnsaddr" protocol by default. So, we have to import go-multiaddr-dns, otherwise I couldn't even build my app.

[anacrolix]

I'm not able to reproduce the failure to build, or any DNS resolution issues. Do you have a code sample? Are you using a go-libp2p Host or some other resolver?

[avbasov]

I've realized the case is not so obvious. I'm sorry. The error will occur if kad-dht is imported before go-libp2p. I use a forked version of kad-dht module, so I have different import order.

Here is an example.

package main

import (
	"context"

	"github.com/libp2p/go-libp2p-kad-dht"

	"github.com/libp2p/go-libp2p"
	"github.com/multiformats/go-multiaddr"
)

func main()  {
	sourceMultiAddr, err := multiaddr.NewMultiaddr("/ip4/0.0.0.0/tcp/21000")
	if err != nil {
		panic(err)
	}

	host, err := libp2p.New(context.Background(), libp2p.ListenAddrs(sourceMultiAddr))
	if err != nil {
		panic(err)
	}
	defer host.Close()

	kad, err := dht.New(context.Background(), host)
	if err != nil {
		panic(err)
	}
	defer kad.Close()
}