libp2p Demos

Demo 1: DHT Peer & Content with Go and JS Nodes

Directory: content-dht-provide-find

What it demonstrates: A new DHT is created by the Go program dht-interop. In a separate terminal or machine, a Node.js program connects to this DHT. One connected, each verifies that it can find the other's content via the DHT.

First terminal:

cd content-dht-provide-find
make
./dht-interop -b ../util/private_key.bin.bootstrapper.Wa

-b means bootstrap mode. In this example, the go program is always the bootstrap node, so -b is always required.

Note that the node ID of dht-interop is always Qm...6aJ9oRuEzWa because it is being read in from ../util/private_key.bin.bootstrapper.Wa (a private key marshalled to X.509 generated by the program util/private-key-gen). This is to keep the peer id of the bootstrap server stable across invocations.

Second terminal: run the command printed out by dht-interop, replacing 127.0.0.1 with the IP of the server where dht-interop is listening. Example:

Running the Node.js program:

cd content-dht-provide-find/js-dht-test
npm install  # first time only
node js-dht-test/index.js /ip4/127.0.0.1/tcp/9876/ipfs/QmehVYruznbyDZuHBV4vEHESpDevMoAovET6aJ9oRuEzWa

Demo 2: PubSub

Directory: pubsub

What it demonstrates: Two Go peers, one JS peer, and one Rust peer are all created and run a chat server using a shared PubSub topic. Typing text in any peer sends it to all the other peers.

(TODO: eliminate centralized bootstrapper; any peer should be able to bootstrap from any other peer and peers should be able to start in any order)

First terminal: Create the bootstrapper node

cd pubsub
./pubsub-interop -b ../util/private_key.bin.bootstrapper.Wa

The bootstrapper creates a new libp2p node, subscribes to the shared topic string, spawns a go routine to emit any publishes to that topic, and then waits forever.

Second terminal: Create a go peer to connect to bootstrapper and publish on the topic

cd pubsub
./pubsub-interop ../util/private_key.bin.peer.Sk

This peer, which is not in bootstrapper mode, creates a node, subscribes to the shared topic string, spawns the same go routine, and then loops forever requesting user input and publishing each line to the topic.

Third terminal: Create a JS peer to connect to bootstrap and publish on topic

cd pubsub/js
npm install  # first time only
node index.js /ip4/127.0.0.1/tcp/9876/ipfs/QmehVYruznbyDZuHBV4vEHESpDevMoAovET6aJ9oRuEzWa

This JS peer will fire off a hello message every few seconds, which the other two subscribing nodes can see.

Fourth terminal: Createa a Rust peer to connect to the bootstrap node and then subscribe and publish on the topic:

cd pubsub/rust
cargo run /ip4/0.0.0.0/tcp/9879
# Wait for it to start up
/dial /ip4/127.0.0.1/tcp/9876
# Now type any message to publish

The Rust peer listens on the CLI-specified port (9879 in the above example), and then the /dial command causes it to dial out to the boostrap host. (TODO: rust-libp2p#471) It is now subscribed to the same topic as the other peers.

If you return to the second, third or fourth terminals and type a message, the bootstrapper and the other 2 peers will all print your message.

In short, you have a chat app on a private libp2p network using PubSub.

Acknowledgements: @jhiesey for DHT (content & peer routing) JS+Go interop, @stebalien for PubSub