raven/README.md
2018-09-29 04:16:52 -07:00

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# 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/5555/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.
**Quick test**: `cd pubsub` and then run `./test/test.sh`. Requires Terminator (eg, `sudo apt-get install terminator`). The rest of this section describes how to test manually.
(**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/5555/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
```
The Rust peer starts up, listens on port 6002, and then dials the boostrap peer. (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.
## Debugging Notes
**JS** To see debug messages from the Node.js program, use the `DEBUG` environment variable:
```
DEBUG="libp2p:floodsub*,libp2p:switch*,mss:*" node index.js [args...]
```
**Go** To see debug messages in Go programs, do this at runtime:
```
IPFS_LOGGING=debug ./pubsub-interop [args...]
```
TODO: describe custom instrumenting the local go code
If you instrument your go code with custom `fmt.Println`'s, then revert back like this:
```
cd $GOPATH
go get -u ./...
```
Other useful commands:
```
go get -u github.com/libp2p/go-libp2p-kad-dht # fetch just Kad DHT repo
```
_Acknowledgements: @jhiesey for DHT (content & peer routing) JS+Go interop, @stebalien for PubSub_