Chai ☕️🌿

A framework for creating TUI SSH programs in Rust, powered by ratatui and russh.

Getting Started

1. Add dependencies

cargo add chai-framework tokio tracing-subscriber

2. Implement your TUI app

use chai_framework::ChaiApp;
use ratatui::prelude::*;

pub struct MyApp {
    quit: bool,
}

impl ChaiApp for MyApp {
    fn new() -> Self {
        Self { quit: false }
    }

    fn update(&mut self) {
        // update state periodically (called by the server)
    }

    fn draw(&mut self, f: &mut Frame) {
        let text = Paragraph::new("Hello from Chai!");
        f.render_widget(text, f.size());
    }

    fn handle_input(&mut self, data: &[u8]) {
        if data == b"q" {
            self.quit = true;
        }
    }

    fn should_quit(&self) -> bool {
        self.quit
    }
}

Why Chai

The Chai framework makes it easy to host your ratatui apps on an SSH server.

First, encapsulate your TUI program within a stateful struct. Then, implement the ChaiApp trait for this struct to satisfy the required interface abstractions. After that, it's simple plug-and-play by providing your new struct to the ChaiServer.

Running a Chai Server

mod app;
use app::MyApp; // your TUI app

use chai_framework::{ChaiServer, load_host_keys};
use russh::{MethodKind, MethodSet, server::Config};

#[tokio::main]
async fn main() {
    // Load a private key (for example: ~/.ssh/id_ed25519)
    let host_key = load_host_keys("/home/your_user/.ssh/id_ed25519")
        .expect("Failed to load host key");

    let mut methods = MethodSet::empty();
    methods.push(MethodKind::None);

    let config = Config {
        keys: vec![host_key],
        methods,
        ..Default::default()
    };

    let mut server = ChaiServer::<MyApp>::new(2222)
        .with_max_connections(32)      // optional (default: 100)
        .with_channel_buffer(1024);    // optional (default: 64)

    server
        .run(config)
        .await
        .expect("Failed running server");
}

Logging

Chai uses tracing.

You can control logging with environment variables:

RUST_LOG=info cargo run

Examples

For examples, see here. Simply run cargo run --example [example name].

chai-framework 2.1.0