0g-storage-node/version-meld/discv5/examples/custom_executor.rs

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2024-01-03 10:24:52 +00:00
//! Demonstrates how to run a basic Discovery v5 Service with a custom tokio executor.
//!
//! Discv5 requires a Tokio executor with all features. A custom exuector can be passed via the
//! configuration parameters. If none is passed, it will use the current runtime that build the
//! `Discv5` struct.
//!
//! To run this example simply run:
//! ```
//! $ cargo run --example custom_executor <BASE64ENR>
//! ```
use discv5::{enr, enr::CombinedKey, Discv5, Discv5ConfigBuilder, Discv5Event};
use std::net::SocketAddr;
fn main() {
// allows detailed logging with the RUST_LOG env variable
let filter_layer = tracing_subscriber::EnvFilter::try_from_default_env()
.or_else(|_| tracing_subscriber::EnvFilter::try_new("info"))
.unwrap();
let _ = tracing_subscriber::fmt()
.with_env_filter(filter_layer)
.try_init();
// listening address and port
let listen_addr = "0.0.0.0:9000".parse::<SocketAddr>().unwrap();
let enr_key = CombinedKey::generate_secp256k1();
// construct a local ENR
let enr = enr::EnrBuilder::new("v4").build(&enr_key).unwrap();
// build the tokio executor
let runtime = tokio::runtime::Builder::new_multi_thread()
.thread_name("Discv5-example")
.enable_all()
.build()
.unwrap();
// default configuration - uses the current executor
let config = Discv5ConfigBuilder::new().build();
// construct the discv5 server
let mut discv5 = Discv5::new(enr, enr_key, config).unwrap();
// if we know of another peer's ENR, add it known peers
if let Some(base64_enr) = std::env::args().nth(1) {
match base64_enr.parse::<enr::Enr<enr::CombinedKey>>() {
Ok(enr) => {
println!(
"ENR Read. ip: {:?}, udp_port {:?}, tcp_port: {:?}",
enr.ip(),
enr.udp(),
enr.tcp()
);
if let Err(e) = discv5.add_enr(enr) {
println!("ENR was not added: {}", e);
}
}
Err(e) => panic!("Decoding ENR failed: {}", e),
}
}
runtime.block_on(async {
// start the discv5 service
discv5.start(listen_addr).await.unwrap();
println!("Server started");
// get an event stream
let mut event_stream = discv5.event_stream().await.unwrap();
loop {
match event_stream.recv().await {
Some(Discv5Event::SocketUpdated(addr)) => {
println!("Nodes ENR socket address has been updated to: {:?}", addr);
}
Some(Discv5Event::Discovered(enr)) => {
println!("A peer has been discovered: {}", enr.node_id());
}
_ => {}
}
}
})
}