Cannot create so many PeerConnections Error

[olizilla]

• Version: 0.32 & 0.31
• Platform: Chrome

Type: Bug-ish

Severity: Low

Description:

Leaving js-ipfs running in Chrome while working on ipld-explorer, I've just started seeing lots of

Uncaught DOMException: Failed to construct 'RTCPeerConnection': Cannot create so many PeerConnections

index.js:88 Uncaught DOMException: Failed to construct 'RTCPeerConnection': Cannot create so many PeerConnections
    at new Peer (http://localhost:3000/static/js/0.chunk.js:212931:14)
    at ClassIsWrapper.dial (http://localhost:3000/static/js/0.chunk.js:106314:21)
    at timeout (http://localhost:3000/static/js/0.chunk.js:97790:30)
    at http://localhost:3000/static/js/0.chunk.js:6579:12
    at http://localhost:3000/static/js/bundle.js:8182:12
    at DialQueue._dialWithTimeout (http://localhost:3000/static/js/0.chunk.js:97797:25)
    at DialQueue._doWork (http://localhost:3000/static/js/0.chunk.js:97752:10)
    at DialQueue.queue.queue (http://localhost:3000/static/js/0.chunk.js:97736:12)

The instance is still functional, but it's one of those error messages that will worry people as it's large and red.

Steps to reproduce the error:

Create a js-ipfs instance in the browser, passing no custom opts. Leave it running for 5mins.

[olizilla]

This is a leak in Google Chrome which started to manifest in version 65.0.3300.0.

• Tracker announce causes chrome-extension to crash due to too many RTCPeerConnections construct webtorrent/webtorrent#1349 (comment)
• https://bugs.chromium.org/p/chromium/issues/detail?id=825576#c24

[olizilla]

What is interesting is i can leave https://explore.ipld.io open for > 10mins in a chrome tab with 0 errors, but working on it locally the errors show up after a couple of minutes. The significant differences between the two are https vs localhost and minified code vs unminified.

[alanshaw]

@jacobheun would you be able to look into this one?

[jacobheun]

@alanshaw I can take a look.

[jacobheun]

@olizilla do you know how many peers your node had? I've had a basic client running the latest ipfs in chrome for a couple of hours and haven't hit the error. I do see lots of websocket errors though (which also need to get addressed).

My peer count is currently floating around 320.

[olizilla]

huh. Running ipld-explorer locally I start getting those error after ~2 mins and with 8 peers.

[olizilla]

ipld-explorer inits js-ipfs like this
https://github.com/ipfs-shipyard/ipld-explorer/blob/d17e6f5d3ee32ab63bc6be94d72455018f24c07e/src/bundles/ipfs.js#L96-L103

It uses a dynamic import to load in the bundle once we're sure it's needed, and then passes any user opts to it at instantiation, which will just be an empty object if there is nothing under the ipfsOpts key in localStorage, which is the case when I get these errors.

[jacobheun]

Okay, if I can't replicate with a basic instance, I will grab the explorer code and give that a go.

[jacobheun]

In order to replicate this with a basic js-ipfs instance I needed to add the wrtc star discovery server address to the swarm list.

const ipfs = new Ipfs({
  config: {
    Addresses: {
      Swarm: [ '/dns4/wrtc-star.discovery.libp2p.io/tcp/443/wss/p2p-webrtc-star' ]
    }
  }
})

I've got a fix for catching these errors at libp2p/js-libp2p-webrtc-star#157