use std::collections::HashMap;
use std::sync::{
atomic::{AtomicBool, Ordering},
Arc,
};
use axum::extract::ws::{Message, WebSocket, WebSocketUpgrade};
use axum::extract::State;
use axum::http::{HeaderMap, HeaderValue, StatusCode};
use axum::response::{IntoResponse, Response};
use axum::routing::get;
use axum::Router;
use futures::{SinkExt, StreamExt};
use tokio::sync::{mpsc, Mutex};
use uuid::Uuid;
use crate::config::Config;
use crate::runtime::store::RuntimeArgsStore;
use crate::runtime::{RuntimeApplyResult, RuntimeScope, RuntimeUpdateRequest};
use crate::support::command_spec::parse_command_spec;
use crate::support::cors::build_cors_layer;
use crate::support::signals::install_signal_handlers;
use crate::support::stdio_child::StdioChild;
const WS_CLIENT_BUFFER: usize = 256;
#[derive(Clone)]
struct AppState {
clients: Arc<Mutex<HashMap<String, mpsc::Sender<serde_json::Value>>>>,
child: Arc<StdioChild>,
runtime: RuntimeArgsStore,
base_headers: HeaderMap,
ready: Arc<AtomicBool>,
}
pub async fn run(
config: Config,
runtime: RuntimeArgsStore,
mut updates: mpsc::Receiver<RuntimeUpdateRequest>,
) -> Result<(), String> {
let stdio_cmd = config.stdio.clone().ok_or("stdio command is required")?;
tracing::info!(" - port: {}", config.port);
tracing::info!(" - stdio: {}", stdio_cmd);
tracing::info!(" - messagePath: {}", config.message_path);
let spec = parse_command_spec(&stdio_cmd)?;
let child = Arc::new(StdioChild::new(spec, true));
let initial_args = runtime.get_effective(None).await;
child.spawn(&initial_args).await?;
let clients: Arc<Mutex<HashMap<String, mpsc::Sender<serde_json::Value>>>> =
Arc::new(Mutex::new(HashMap::new()));
let ready = Arc::new(AtomicBool::new(false));
let state = AppState {
clients: clients.clone(),
child: child.clone(),
runtime: runtime.clone(),
base_headers: header_map_from(&config.headers),
ready: ready.clone(),
};
let runtime_child = child.clone();
let runtime_store = runtime.clone();
tokio::spawn(async move {
while let Some(req) = updates.recv().await {
let result = match req.update.scope {
RuntimeScope::Global => {
let update_result = runtime_store.update_global(req.update.update).await;
if update_result.restart_needed {
let args = runtime_store.get_effective(None).await;
if runtime_child.restart(&args).await.is_err() {
RuntimeApplyResult::error("Failed to restart child")
} else {
RuntimeApplyResult::ok("Restarted child with new runtime args", true)
}
} else {
RuntimeApplyResult::ok("Updated runtime args", false)
}
}
RuntimeScope::Session(_) => RuntimeApplyResult::error(
"Per-session runtime overrides are not supported for stdio→WS",
),
};
let _ = req.respond_to.send(result);
}
});
let mut router = Router::new()
.route(&config.message_path, get(ws_handler))
.with_state(state.clone());
for ep in &config.health_endpoints {
let state = state.clone();
let path = ep.clone();
router = router.route(
&path,
get(move || async move { health_handler(state.clone()).await }),
);
}
if let Some(cors) = build_cors_layer(&config.cors) {
router = router.layer(cors);
}
install_signal_handlers(None);
let mut rx = child.subscribe();
tokio::spawn(async move {
loop {
let msg = match rx.recv().await {
Ok(msg) => msg,
Err(tokio::sync::broadcast::error::RecvError::Lagged(skipped)) => {
tracing::warn!(
"stdio->ws child output receiver lagged by {skipped} messages; continuing"
);
continue;
}
Err(tokio::sync::broadcast::error::RecvError::Closed) => break,
};
let mut target_id: Option<String> = None;
let mut outgoing = msg.clone();
if let Some((client_id, raw_id)) = strip_prefixed_id(&msg) {
target_id = Some(client_id);
if let Some(obj) = outgoing.as_object_mut() {
obj.insert("id".to_string(), raw_id);
}
}
if let Some(target) = target_id {
let sender = {
let clients_guard = clients.lock().await;
clients_guard.get(&target).cloned()
};
if let Some(sender) = sender {
if sender.send(outgoing).await.is_err() {
let mut clients_guard = clients.lock().await;
clients_guard.remove(&target);
}
}
continue;
}
let senders: Vec<(String, mpsc::Sender<serde_json::Value>)> = {
let clients_guard = clients.lock().await;
clients_guard
.iter()
.map(|(id, sender)| (id.clone(), sender.clone()))
.collect()
};
let mut dead = Vec::new();
for (id, sender) in senders {
if sender.send(outgoing.clone()).await.is_err() {
dead.push(id);
}
}
if !dead.is_empty() {
let mut clients_guard = clients.lock().await;
for id in dead {
clients_guard.remove(&id);
}
}
}
});
ready.store(true, Ordering::SeqCst);
let addr: std::net::SocketAddr = ([0, 0, 0, 0], config.port).into();
tracing::info!("Listening on port {}", config.port);
tracing::info!(
"WebSocket endpoint: ws://localhost:{}{}",
config.port,
config.message_path
);
let listener = tokio::net::TcpListener::bind(addr)
.await
.map_err(|err| err.to_string())?;
axum::serve(listener, router.into_make_service())
.await
.map_err(|err| err.to_string())
}
async fn ws_handler(ws: WebSocketUpgrade, State(state): State<AppState>) -> impl IntoResponse {
ws.on_upgrade(move |socket| handle_socket(socket, state))
}
async fn handle_socket(stream: WebSocket, state: AppState) {
let client_id = Uuid::new_v4().to_string();
let (mut sender_ws, mut receiver_ws) = stream.split();
let (tx, mut rx) = mpsc::channel::<serde_json::Value>(WS_CLIENT_BUFFER);
{
let mut clients = state.clients.lock().await;
clients.insert(client_id.clone(), tx);
}
let child = state.child.clone();
let send_task = tokio::spawn(async move {
while let Some(msg) = rx.recv().await {
if let Ok(text) = serde_json::to_string(&msg) {
if sender_ws.send(Message::Text(text.into())).await.is_err() {
break;
}
}
}
});
let client_id_clone = client_id.clone();
let recv_task = tokio::spawn(async move {
while let Some(Ok(message)) = receiver_ws.next().await {
if let Message::Text(text) = message {
if let Ok(mut json) = serde_json::from_str::<serde_json::Value>(&text) {
if let Some(id) = json.get("id").cloned() {
let prefixed = prefix_id(&client_id_clone, &id);
if let Some(obj) = json.as_object_mut() {
obj.insert("id".to_string(), prefixed);
}
}
let _ = child.send(&json).await;
}
}
}
});
let _ = tokio::join!(send_task, recv_task);
let mut clients = state.clients.lock().await;
clients.remove(&client_id);
}
async fn health_handler(state: AppState) -> impl IntoResponse {
if !state.child.is_alive().await {
return (
StatusCode::INTERNAL_SERVER_ERROR,
"Child process has been killed",
)
.into_response();
}
if !state.ready.load(Ordering::SeqCst) {
return (StatusCode::INTERNAL_SERVER_ERROR, "Server is not ready").into_response();
}
let mut response = (StatusCode::OK, "ok").into_response();
apply_headers(&state, &mut response).await;
response
}
async fn apply_headers(state: &AppState, response: &mut Response) {
let runtime = state.runtime.get_effective(None).await;
let headers = merge_headers(&state.base_headers, &runtime.headers);
let header_map = response.headers_mut();
for (key, value) in headers.iter() {
header_map.insert(key, value.clone());
}
}
fn header_map_from(headers: &std::collections::HashMap<String, String>) -> HeaderMap {
let mut map = HeaderMap::new();
for (k, v) in headers {
if let (Ok(name), Ok(value)) = (
axum::http::header::HeaderName::from_bytes(k.as_bytes()),
HeaderValue::from_str(v),
) {
map.insert(name, value);
}
}
map
}
fn merge_headers(
base: &HeaderMap,
overlay: &std::collections::HashMap<String, String>,
) -> HeaderMap {
let mut merged = base.clone();
for (k, v) in overlay {
if let (Ok(name), Ok(value)) = (
axum::http::header::HeaderName::from_bytes(k.as_bytes()),
HeaderValue::from_str(v),
) {
merged.insert(name, value);
}
}
merged
}
fn prefix_id(client_id: &str, id: &serde_json::Value) -> serde_json::Value {
match id {
serde_json::Value::String(s) => serde_json::Value::String(format!("{client_id}:{s}")),
serde_json::Value::Number(n) => serde_json::Value::String(format!("{client_id}:{n}")),
_ => serde_json::Value::String(format!("{client_id}:{id}")),
}
}
fn strip_prefixed_id(message: &serde_json::Value) -> Option<(String, serde_json::Value)> {
let id_val = message.get("id")?;
let id_str = id_val.as_str()?;
let mut parts = id_str.splitn(2, ':');
let client = parts.next()?.to_string();
let raw = parts.next()?.to_string();
let raw_id = raw
.parse::<i64>()
.map(|num| serde_json::Value::Number(num.into()))
.unwrap_or_else(|_| serde_json::Value::String(raw));
Some((client, raw_id))
}