feat: hot-reloading of config file

rpxy-bin/src/main.rs

@@ -11,7 +11,12 @@ mod constants;
 mod error;
 mod log;
 
-use crate::{config::build_settings, log::*};
+use crate::{
+  config::{build_settings, parse_opts, ConfigToml, ConfigTomlReloader},
+  constants::CONFIG_WATCH_DELAY_SECS,
+  log::*,
+};
+use hot_reload::{ReloaderReceiver, ReloaderService};
 use rpxy_lib::entrypoint;
 
 fn main() {
@@ -23,17 +28,68 @@ fn main() {
   let runtime = runtime_builder.build().unwrap();
 
   runtime.block_on(async {
-    let (proxy_conf, app_conf) = match build_settings() {
-      Ok(g) => g,
-      Err(e) => {
-        error!("Invalid configuration: {}", e);
+    // Initially load config
+    let Ok(config_path) = parse_opts() else {
+        error!("Invalid toml file");
         std::process::exit(1);
-      }
     };
+    let (config_service, config_rx) =
+      ReloaderService::<ConfigTomlReloader, ConfigToml>::new(&config_path, CONFIG_WATCH_DELAY_SECS, false)
+        .await
+        .unwrap();
 
-    entrypoint(proxy_conf, app_conf, runtime.handle().clone())
-      .await
-      .unwrap()
+    tokio::select! {
+      _ = config_service.start() => {
+        error!("config reloader service exited");
+      }
+      _ = rpxy_service(config_rx, runtime.handle().clone()) => {
+        error!("rpxy service existed");
+      }
+    }
   });
-  warn!("rpxy exited!");
+}
+
+async fn rpxy_service(
+  mut config_rx: ReloaderReceiver<ConfigToml>,
+  runtime_handle: tokio::runtime::Handle,
+) -> Result<(), anyhow::Error> {
+  // Initial loading
+  config_rx.changed().await?;
+  let config_toml = config_rx.borrow().clone().unwrap();
+  let (mut proxy_conf, mut app_conf) = match build_settings(&config_toml) {
+    Ok(v) => v,
+    Err(e) => {
+      error!("Invalid configuration: {e}");
+      return Err(anyhow::anyhow!(e));
+    }
+  };
+
+  // Continuous monitoring
+  loop {
+    tokio::select! {
+      _ = entrypoint(&proxy_conf, &app_conf, &runtime_handle) => {
+        error!("rpxy entrypoint exited");
+        break;
+      }
+      _ = config_rx.changed() => {
+        if config_rx.borrow().is_none() {
+          error!("Something wrong in config reloader receiver");
+          break;
+        }
+        let config_toml = config_rx.borrow().clone().unwrap();
+        match build_settings(&config_toml) {
+          Ok((p, a)) => {
+            (proxy_conf, app_conf) = (p, a)
+          },
+          Err(e) => {
+            error!("Invalid configuration. Configuration does not updated: {e}");
+            continue;
+          }
+        };
+        info!("Configuration updated. Force to re-bind TCP/UDP sockets");
+      }
+      else => break
+    }
+  }
+  Ok(())
 }