A library to build custom networking layers for decentralized applications
SwarmNL is a library designed for P2P networking in distributed systems. It's lightweight, scalable, and easy to configure, making it perfect for decentralized applications. Powered by libp2p, SwarmNL simplifies networking so developers can focus on building.
SwarmNL makes buiding a peer-to-peer decentralized and distributed networking stack for your application a breeze. With SwarmNL, you can effortlessly configure nodes, tailor network conditions, and fine-tune behaviors specific to your project's needs, allowing you to dive into networking without any hassle.
Say goodbye to the complexities of networking and hello to simplicity. With SwarmNL, all the hard work is done for you, leaving you to focus on simple configurations and your application logic.
Have a look at some tutorials that demonstrate the use of SwarmNl in various contexts:
- Echo server tutorial: demonstrates a simple use case of setting up a node and querying the network layer.
- File sharing application tutorial: demonstrates interacting with the DHT and sending/recieving RPCs from peers.
- Simple game tutorial: demonstrates communicating with peers over the network through gossiping.
Visit the deployed Rust docs here.
SwarmNL provides a simple interface to configure a node and specify parameters to dictate its behaviour. This includes:
- Selection and configuration of the transport layers to be supported by the node
- Selection of cryptographic keypairs (ed25519, RSA, secp256k1, ecdsa)
- Storage and retrieval of keypair locally
- PeerID and multiaddress generation
- Protocol specification and handlers
- Event handlers for network events and logging
//! Using the default node setup configuration and the default network event handler
// Default config
let config = BootstrapConfig::default();
// Default network handler
let handler = DefaultHandler;
// Build node or network core
let node = CoreBuilder::with_config(config, handler)
.build()
.await
.unwrap();
//! Using a custom node setup configuration and a custom network event handler
// Custom configuration
// a. Using config from an `.ini` file
let config = BootstrapConfig::from_file("bootstrap_config.ini");
// b. Using config methods
let mut bootnode = HashMap::new(); // Bootnodes
let ports = (1509, 2710); // TCP, UDP ports
bootnode.insert(
PeerId::random(),
"/ip4/x.x.x.x/tcp/1509".to_string()
);
let config = BootstrapConfig::new()
.with_bootnodes(bootnode)
.with_tcp(ports.0)
.with_udp(ports.1);
// Custom event handler
use swarm_nl::core::EventHandler;
#[derive(Clone)]
struct ApplicationState{
name: String,
version: f32,
}
// Define custom behaviour to respond to network events
impl EventHandler for AppState {
fn new_listen_addr(
&mut self,
local_peer_id: PeerId,
listener_id: ListenerId,
addr: Multiaddr,
) {
// Announce interfaces we're listening on
println!("Peer id: {}", local_peer_id);
println!("We're listening on the {}", addr);
}
// Echo data recieved from a RPC
fn rpc_handle_incoming_message(&mut self, data: Vec<Vec<u8>>) -> Vec<Vec<u8>> {
println!("Recvd incoming RPC: {:?}", data);
data
}
// Handle the incoming gossip message
fn gossipsub_handle_incoming_message(&mut self, source: PeerId, data: Vec<String>) {
println!("Recvd incoming gossip: {:?}", data);
}
}
// Define custom event handler
let state = ApplicationState {
name: String::from("SwarmNL"),
version: 0.1
}
// Build node or network core
let node = CoreBuilder::with_config(config, state)
.build()
.await
.unwrap();Please look at a template .ini file here for configuring a node in the network.
SwarmNL provides two ways to make application state changes:
- Event Handlers: Registered event handlers can modify state in response to network events.
- Network Core (or Node): The node construct is the primary way to change internal application state. The application state is accessible through the
statefield of the node or network core.
This setup ensures proper synchronization using effective synchronization primitives. Network events are non-deterministic, so they can change state at any time. To manage this, we use a Mutex to lock the state during changes.
When an event handler method runs, it has already acquired the application state Mutex. The entire duration of the handler's execution is a critical section. It is important to avoid long computations or delays in releasing the Mutex, keeping the function simple and quick.
// A simple event handler method that modifies application state
// ...
/// Event that announces the arrival of a gossip message.
fn gossipsub_incoming_message_handled(&mut self, _source: PeerId, data: Vec<String>) {
println!(
"[[Node {}]] >> incoming data from peer -> {}: {}",
self.node, data[0], data[1]
);
// Parse our data
match data[0].as_str() {
"guess" => {
// Our remote peer has made a guess
let remote_peer_guess = data[1].parse::<i32>().unwrap();
// Compare
if self.current_guess > remote_peer_guess {
// Modify app state
self.score += 1;
}
},
"win" => {
// Set our score to -1
// Game over
self.score = -1;
},
_ => {},
}
if self.score != -1 && self.score != HIGH_SCORE {
println!(
"[[Node {}]] >> Node ({}) score: {}",
self.node, self.node, self.score
);
}
}
// ...The application state is exposed through the state field in the network core (or node). This field is protected by a Mutex to prevent race conditions when network event handlers are triggered. To access or modify the application state, the Mutex must be acquired first.
// Snippet from the game example that modifies internal application state
// ...
// If the remote has won, our handler will set our score to -1
if node_2.state.lock().await.score == HIGH_SCORE {
// We've won!
println!(
"[[Node {}]] >> Congratulations! Node 2 is the winner.",
node_2.state.lock().await.node
);
// Inform Node 1
// Prepare a gossip request
let gossip_request = AppData::GossipsubBroadcastMessage {
topic: GOSSIP_NETWORK.to_string(),
message: vec!["win".to_string(), random_u32.to_string()],
};
// Gossip our random value to our peers
let _ = node_2.query_network(gossip_request).await;
break;
} else if node_2.state.lock().await.score == -1 {
// We lost :(
println!(
"[[Node {}]] >> Game Over! Node 1 is the winner.",
node_2.state.lock().await.node
);
break;
}
// ...For communication, SwarmNL leverages the powerful capabilities of libp2p. These includes:
- The Kadmlia DHT: Developers can use the DHT to store infomation and leverage the capabilities of the DHT to build powerful applications, easily.
- A simple RPC mechanism to exchange data quickly between peers.
- Gossiping: SwarmNL uses the Gossipsub 1.1 protocol, specified by the libp2p spec.
//! Communicate with remote nodes using the simple and familiar async-await paradigm.
// Build node or network core
let node = CoreBuilder::with_config(config, state)
.build()
.await
.unwrap();
// Communication interfaces
// a. Kademlia DHT e.g
// Prepare an kademlia `store_record` request to send to the network layer
let (key, value, expiration_time, explicit_peers) = (
KADEMLIA_TEST_KEY.as_bytes().to_vec(),
KADEMLIA_TEST_VALUE.as_bytes().to_vec(),
None,
None,
);
let kad_request = AppData::KademliaStoreRecord {
key: key.clone(),
value,
expiration_time,
explicit_peers,
};
// Send request
if let Ok(result) = node.query_network(kad_request).await {
assert_eq!(KademliaStoreRecordSuccess,result);
}
// b. RPC (request-response) e.g
// Prepare a RPC fetch request
let fetch_key = vec!["SomeFetchKey".as_bytes().to_vec()];
let fetch_request = AppData::FetchData {
keys: fetch_key.clone(),
peer: node4_peer_id,
};
// Get a stream id to track the request
let stream_id = node.send_to_network(fetch_request).await.unwrap();
// Poll for the result
if let Ok(result) = node.recv_from_network(stream_id).await {
// Here, the request data was simply echoed by the remote peer
assert_eq!(AppResponse::FetchData(fetch_key), result);
}
// c. Gossiping e.g
// Prepare gossip request
let gossip_request = AppData::GossipsubBroadcastMessage {
topic: GOSSIP_NETWORK.to_string(),
message: vec!["Daniel".to_string(), "Deborah".to_string()],
};
if let Ok(result) = node.query_network(gossip_request).await {
assert_eq!(AppResponse::GossipsubBroadcastSuccess, result);
}In Development 👷:
- Node failure handling involving reconnection strategies, failover mechanisms etc.
- Scaling involving techniques like sharding, data forwarding etc.
- IPFS upload and download interfaces.
In essence, SwarmNL is designed to simplify networking so you can focus on building that world-changing application of yours! Cheers! 🥂
