go-libp2p-relay

An example that demonstrates how to use circuit relay.

This is an example that quickly shows how to use the github.com/libp2p/go-libp2p-circuit package to build and use relay peer.

This example is based on the libp2p/go-libp2p-examples/relay modification, and the difference from the source code is that this example splits a file in the original text into 3 peers. And a particularly important change is

// code in https://github.com/libp2p/go-libp2p-examples/blob/b7ac9e91865656b3ec13d18987a09779adad49dc/relay/main.go#L68
// Creates a relay address
relayaddr, err := ma.NewMultiaddr("/p2p-circuit/ipfs/" + h3.ID().Pretty())
if err != nil {
	panic(err)
}

relayaddr, err := ma.NewMultiaddr(fmt.Printf("%s/p2p/%s\n", h2.Addrs()[len(h2.Addrs())-1], h2.ID()) + "/p2p-circuit/ipfs/" + h3.ID().Pretty())
if err != nil {
	panic(err)
}

NodeA and NodeB are behind NAT, reverse proxies, firewalls and/or simply don't able to establish a direct connection to each other.

Now we can let them establish a connection by step:

NodeA -> NodeRelay

NodeB -> NdoeRelay

NodeA -> NodeB

NodeA and NodeB can be deployed separately on servers on defferent networks.

NodeRelay must be deployed on server on a publicly accessible ip:port.

Usage

NodeA, NodeB, NodeRelay can be deployed separately on different network servers.

Run Node Relay

> cd go-libp2p-relay/NodeRelay
> go run node.go

/ip4/127.0.0.1/tcp/53100/p2p/QmUtH7d63G1jhbfdqUzQ7HeCkxVG2GVukTjkcs5ZTDLx6N
/ip4/xxx.xxx.xxx.xxx/tcp/53100/p2p/QmUtH7d63G1jhbfdqUzQ7HeCkxVG2GVukTjkcs5ZTDLx6N

xxx.xxx.xxx.xxx is your server public IP

Run Node A

> cd go-libp2p-relay/NodeA
> go run node.go -relay /ip4/xxx.xxx.xxx.xxx/tcp/53100/p2p/QmUtH7d63G1jhbfdqUzQ7HeCkxVG2GVukTjkcs5ZTDLx6N

Node A ID:  Qmb1AQPRCvFTz1rj4CqNuFs6NsEiJcpnkFRzzcZRAVfVgD

Run Node B

> cd go-libp2p-relay/NodeB
> go run node.go -relay /ip4/xxx.xxx.xxx.xxx/tcp/53100/p2p/QmUtH7d63G1jhbfdqUzQ7HeCkxVG2GVukTjkcs5ZTDLx6N -dial Qmb1AQPRCvFTz1rj4CqNuFs6NsEiJcpnkFRzzcZRAVfVgD

Okay, no connection from h1 to h3:  failed to dial Qmb1AQPRCvFTz1rj4CqNuFs6NsEiJcpnkFRzzcZRAVfVgD: no addresses
Just as we suspected
end

-dial Qmb1AQPRCvFTz1rj4CqNuFs6NsEiJcpnkFRzzcZRAVfVgD
-dial NodeA ID that can be found in the terminal output of server Node A

If all goes well, you will see the output Meow! It worked! at the terminal of NodeA.

Thanks

libp2p/go-libp2p-examples
@raulk
@upperwal