How can I get a PeerInfo from a Host?

Question

I'm trying to get a PeerInfo from a libp2p.Host instance. I'm able to get a list of multiaddr.Multiaddrs by calling Host.Addrs(), but I'm unable to convert these into a valid peerstore.PeerInfo.

Here is my attempt, which panics with the error panic: invalid p2p multiaddr.

package main

import (
    "log"

    "github.com/SentimensRG/ctx"
    "github.com/SentimensRG/ctx/sigctx"

    libp2p "github.com/libp2p/go-libp2p"
    ps "github.com/libp2p/go-libp2p-peerstore"
)

var c = ctx.AsContext(sigctx.New())

func main() {
    h0, err := libp2p.New(c)
    if err != nil {
        panic(err)
    }    

    addr0 := h0.Addrs()[1]

    _, err := ps.InfoFromP2pAddr(addr0)
    if err != nil {
        panic(err)
    }
}

How can I get a peerstore.PeerInfo from a libp2p.Host?

Answer 1

PeerInfo is a struct that encapsulates a peer ID and its multiaddrs. To build a PeerInfo from a Host easily, you can simply do the following:

pi := PeerInfo{
        ID: host.ID(),
        Addrs: host.Addrs(),
}

pstore.InfoFromP2pAddr() requires a multiaddr with a p2p or ipfs component in order to populate the PeerInfo.ID element.

That said, we could definitely make it easier to obtain a PeerInfo from a Host. I'll work on it ;-)