feat(metrics): add real-time throughput sampling and byte-counting metrics

rust/crates/rustproxy/src/lib.rs

@@ -71,6 +71,7 @@ pub struct RustProxy {
     cert_manager: Option<Arc<tokio::sync::Mutex<CertManager>>>,
     challenge_server: Option<challenge_server::ChallengeServer>,
     renewal_handle: Option<tokio::task::JoinHandle<()>>,
+    sampling_handle: Option<tokio::task::JoinHandle<()>>,
     nft_manager: Option<NftManager>,
     started: bool,
     started_at: Option<Instant>,
@@ -100,14 +101,19 @@ impl RustProxy {
         let cert_manager = Self::build_cert_manager(&options)
             .map(|cm| Arc::new(tokio::sync::Mutex::new(cm)));
 
+        let retention = options.metrics.as_ref()
+            .and_then(|m| m.retention_seconds)
+            .unwrap_or(3600) as usize;
+
         Ok(Self {
             options,
             route_table: ArcSwap::from(Arc::new(route_manager)),
             listener_manager: None,
-            metrics: Arc::new(MetricsCollector::new()),
+            metrics: Arc::new(MetricsCollector::with_retention(retention)),
             cert_manager,
             challenge_server: None,
             renewal_handle: None,
+            sampling_handle: None,
             nft_manager: None,
             started: false,
             started_at: None,
@@ -276,6 +282,21 @@ impl RustProxy {
         self.started = true;
         self.started_at = Some(Instant::now());
 
+        // Start the throughput sampling task
+        let metrics = Arc::clone(&self.metrics);
+        let interval_ms = self.options.metrics.as_ref()
+            .and_then(|m| m.sample_interval_ms)
+            .unwrap_or(1000);
+        self.sampling_handle = Some(tokio::spawn(async move {
+            let mut interval = tokio::time::interval(
+                std::time::Duration::from_millis(interval_ms)
+            );
+            loop {
+                interval.tick().await;
+                metrics.sample_all();
+            }
+        }));
+
         // Apply NFTables rules for routes using nftables forwarding engine
         self.apply_nftables_rules(&self.options.routes.clone()).await;
 
@@ -478,6 +499,11 @@ impl RustProxy {
 
         info!("Stopping RustProxy...");
 
+        // Stop sampling task
+        if let Some(handle) = self.sampling_handle.take() {
+            handle.abort();
+        }
+
         // Stop renewal timer
         if let Some(handle) = self.renewal_handle.take() {
             handle.abort();