libp2p pubsub room failing to find peers

[ajayrao80]

Version: libp2p 0.23.1
libp2p-websocket-star 0.8.1
Node js 10.0

Platform: 64-bit (Windows 10).
Type: Bug (Maybe)

Severity: High

Description: I'm trying to create a libp2p pubsub room. I have two instances (in same machine) joined the same room but can't find each other. I've set a time interval to check the number of peers in the room but it's 0 always.

Here's the code:

const defaultsDeep = require('@nodeutils/defaults-deep')
const libp2p = require('libp2p')
const PeerId = require('peer-id')
const PeerInfo = require('peer-info')
const WSStar = require('libp2p-websocket-star')

PeerId.create((err, id) => {
	if(err){ throw err }
	
	const peerInfo = new PeerInfo(id)
	peerInfo.multiaddrs.add('/dns4/ws-star.discovery.libp2p.io/tcp/443/wss/p2p-websocket-star/ipfs/' + peerInfo.id._idB58String)
	
	 const wsS = new WSStar({ id: id }) 
	
        const defaults = {
          modules: {
            transport: [
	       wsS
            ],
	    peerDiscovery: [
               wsS.discovery
            ]
          },
           config: {
	       EXPERIMENTAL:{
	 	  pubsub:true
	       }
            }
         }
	
	
	 const node = new libp2p(defaultsDeep({peerInfo:peerInfo}, defaults))
	 node.start((err) => {
              if (err) { throw err }
	
              const topic = 'abcd'
	      const receiveMsg = (msg) => console.log(msg.data.toString())
 
     	      node.pubsub.subscribe(topic, receiveMsg, (err) => {
	         if (err) {
		    return console.error(`failed to subscribe to ${topic}`, err)
	         }
	         console.log(`subscribed to ${topic}`)
	      })
	
	      setInterval(() => {
	          node.pubsub.peers(topic, (err, peerIds) => {
		   if (err) { throw err }
		   console.log(peerIds)
	      })
	 }, 3000)

  })
})

[ajayrao80]

I have an update on this. When one of the instances is ipfs, it works fine. But when both instances are libp2p instances, it doesn't work. Anybody has any idea why?

[jacobheun]

Libp2p doesn't currently automatically handle dialing to peers that are discovered. This works with an ipfs node because ipfs is listening to the 'peer:discovery' event on the node and triggering dials to each peer it finds. While your nodes might be setup to the same room, they're not connected yet, so pubsub won't work.

The current pubsub example uses MulticastDNS for discovery but the idea is the same, https://github.com/libp2p/js-libp2p/blob/master/examples/pubsub/1.js#L65, you'll just need to change once to on as other peers will be connected to the discovery node.

[ajayrao80]

That worked. Thank you so much.