lssa/lez/sequencer/service/src/main.rs

use std::path::PathBuf;

use anyhow::Result;
use clap::Parser;
use log::{error, info};
use tokio_util::sync::CancellationToken;

#[derive(Debug, Parser)]
#[clap(version)]
struct Args {
    #[clap(name = "config")]
    config_path: PathBuf,
    #[clap(short, long, default_value = "3040")]
    port: u16,
    /// Override the config's home directory (`RocksDB` + bedrock signing key),
    /// so multiple instances can share one config file.
    #[clap(long)]
    home: Option<PathBuf>,
}

#[tokio::main]
#[expect(
    clippy::integer_division_remainder_used,
    reason = "Generated by select! macro, can't be easily rewritten to avoid this lint"
)]
async fn main() -> Result<()> {
    env_logger::init();

    let Args {
        config_path,
        port,
        home,
    } = Args::parse();

    // TODO: handle this cancellation token more gracefully within Sequencer service
    // similar to how we do in Indexer
    let cancellation_token = listen_for_shutdown_signal();

    let mut config = sequencer_service::SequencerConfig::from_path(&config_path)?;
    if let Some(home) = home {
        config.home = home;
    }
    let sequencer_handle = sequencer_service::run(config, port).await?;

    tokio::select! {
        () = cancellation_token.cancelled() => {
            info!("Shutting down sequencer...");
        }
        Err(err) = sequencer_handle.failed() => {
            error!("Sequencer failed unexpectedly: {err}");
        }
    }

    info!("Sequencer shutdown complete");

    Ok(())
}

fn listen_for_shutdown_signal() -> CancellationToken {
    let cancellation_token = CancellationToken::new();
    let cancellation_token_clone = cancellation_token.clone();

    tokio::spawn(async move {
        if let Err(err) = tokio::signal::ctrl_c().await {
            error!("Failed to listen for Ctrl-C signal: {err}");
            return;
        }
        info!("Received Ctrl-C signal");
        cancellation_token_clone.cancel();
    });

    cancellation_token
}