feat(metrics): add frontend and backend protocol distribution metrics

rust/crates/rustproxy-metrics/src/collector.rs

@@ -33,6 +33,9 @@ pub struct Metrics {
     pub total_datagrams_out: u64,
     // Protocol detection cache snapshot (populated by RustProxy from HttpProxyService)
     pub detected_protocols: Vec<ProtocolCacheEntryMetric>,
+    // Protocol distribution for frontend (client→proxy) and backend (proxy→upstream)
+    pub frontend_protocols: ProtocolMetrics,
+    pub backend_protocols: ProtocolMetrics,
 }
 
 /// Per-route metrics.
@@ -99,6 +102,23 @@ pub struct ProtocolCacheEntryMetric {
     pub h3_consecutive_failures: Option<u32>,
 }
 
+/// Protocol distribution metrics for frontend (client→proxy) and backend (proxy→upstream).
+/// Tracks active and total counts for each protocol category.
+#[derive(Debug, Clone, Serialize, Deserialize, Default)]
+#[serde(rename_all = "camelCase")]
+pub struct ProtocolMetrics {
+    pub h1_active: u64,
+    pub h1_total: u64,
+    pub h2_active: u64,
+    pub h2_total: u64,
+    pub h3_active: u64,
+    pub h3_total: u64,
+    pub ws_active: u64,
+    pub ws_total: u64,
+    pub other_active: u64,
+    pub other_total: u64,
+}
+
 /// Statistics snapshot.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -170,6 +190,30 @@ pub struct MetricsCollector {
     total_datagrams_in: AtomicU64,
     total_datagrams_out: AtomicU64,
 
+    // ── Frontend protocol tracking (h1/h2/h3/ws/other) ──
+    frontend_h1_active: AtomicU64,
+    frontend_h1_total: AtomicU64,
+    frontend_h2_active: AtomicU64,
+    frontend_h2_total: AtomicU64,
+    frontend_h3_active: AtomicU64,
+    frontend_h3_total: AtomicU64,
+    frontend_ws_active: AtomicU64,
+    frontend_ws_total: AtomicU64,
+    frontend_other_active: AtomicU64,
+    frontend_other_total: AtomicU64,
+
+    // ── Backend protocol tracking (h1/h2/h3/ws/other) ──
+    backend_h1_active: AtomicU64,
+    backend_h1_total: AtomicU64,
+    backend_h2_active: AtomicU64,
+    backend_h2_total: AtomicU64,
+    backend_h3_active: AtomicU64,
+    backend_h3_total: AtomicU64,
+    backend_ws_active: AtomicU64,
+    backend_ws_total: AtomicU64,
+    backend_other_active: AtomicU64,
+    backend_other_total: AtomicU64,
+
     // ── Lock-free pending throughput counters (hot path) ──
     global_pending_tp_in: AtomicU64,
     global_pending_tp_out: AtomicU64,
@@ -221,6 +265,26 @@ impl MetricsCollector {
             total_http_requests: AtomicU64::new(0),
             pending_http_requests: AtomicU64::new(0),
             http_request_throughput: Mutex::new(ThroughputTracker::new(retention_seconds)),
+            frontend_h1_active: AtomicU64::new(0),
+            frontend_h1_total: AtomicU64::new(0),
+            frontend_h2_active: AtomicU64::new(0),
+            frontend_h2_total: AtomicU64::new(0),
+            frontend_h3_active: AtomicU64::new(0),
+            frontend_h3_total: AtomicU64::new(0),
+            frontend_ws_active: AtomicU64::new(0),
+            frontend_ws_total: AtomicU64::new(0),
+            frontend_other_active: AtomicU64::new(0),
+            frontend_other_total: AtomicU64::new(0),
+            backend_h1_active: AtomicU64::new(0),
+            backend_h1_total: AtomicU64::new(0),
+            backend_h2_active: AtomicU64::new(0),
+            backend_h2_total: AtomicU64::new(0),
+            backend_h3_active: AtomicU64::new(0),
+            backend_h3_total: AtomicU64::new(0),
+            backend_ws_active: AtomicU64::new(0),
+            backend_ws_total: AtomicU64::new(0),
+            backend_other_active: AtomicU64::new(0),
+            backend_other_total: AtomicU64::new(0),
             global_pending_tp_in: AtomicU64::new(0),
             global_pending_tp_out: AtomicU64::new(0),
             route_pending_tp: DashMap::new(),
@@ -411,6 +475,62 @@ impl MetricsCollector {
         self.total_datagrams_out.fetch_add(1, Ordering::Relaxed);
     }
 
+    // ── Frontend/backend protocol distribution tracking ──
+
+    /// Get the (active, total) counter pair for a frontend protocol.
+    fn frontend_proto_counters(&self, proto: &str) -> (&AtomicU64, &AtomicU64) {
+        match proto {
+            "h2" => (&self.frontend_h2_active, &self.frontend_h2_total),
+            "h3" => (&self.frontend_h3_active, &self.frontend_h3_total),
+            "ws" => (&self.frontend_ws_active, &self.frontend_ws_total),
+            "other" => (&self.frontend_other_active, &self.frontend_other_total),
+            _ => (&self.frontend_h1_active, &self.frontend_h1_total), // h1 + default
+        }
+    }
+
+    /// Get the (active, total) counter pair for a backend protocol.
+    fn backend_proto_counters(&self, proto: &str) -> (&AtomicU64, &AtomicU64) {
+        match proto {
+            "h2" => (&self.backend_h2_active, &self.backend_h2_total),
+            "h3" => (&self.backend_h3_active, &self.backend_h3_total),
+            "ws" => (&self.backend_ws_active, &self.backend_ws_total),
+            "other" => (&self.backend_other_active, &self.backend_other_total),
+            _ => (&self.backend_h1_active, &self.backend_h1_total), // h1 + default
+        }
+    }
+
+    /// Record a frontend request/connection opened with a given protocol.
+    pub fn frontend_protocol_opened(&self, proto: &str) {
+        let (active, total) = self.frontend_proto_counters(proto);
+        active.fetch_add(1, Ordering::Relaxed);
+        total.fetch_add(1, Ordering::Relaxed);
+    }
+
+    /// Record a frontend request/connection closed with a given protocol.
+    pub fn frontend_protocol_closed(&self, proto: &str) {
+        let (active, _) = self.frontend_proto_counters(proto);
+        let val = active.load(Ordering::Relaxed);
+        if val > 0 {
+            active.fetch_sub(1, Ordering::Relaxed);
+        }
+    }
+
+    /// Record a backend connection opened with a given protocol.
+    pub fn backend_protocol_opened(&self, proto: &str) {
+        let (active, total) = self.backend_proto_counters(proto);
+        active.fetch_add(1, Ordering::Relaxed);
+        total.fetch_add(1, Ordering::Relaxed);
+    }
+
+    /// Record a backend connection closed with a given protocol.
+    pub fn backend_protocol_closed(&self, proto: &str) {
+        let (active, _) = self.backend_proto_counters(proto);
+        let val = active.load(Ordering::Relaxed);
+        if val > 0 {
+            active.fetch_sub(1, Ordering::Relaxed);
+        }
+    }
+
     // ── Per-backend recording methods ──
 
     /// Record a successful backend connection with its connect duration.
@@ -866,6 +986,30 @@ impl MetricsCollector {
             total_datagrams_in: self.total_datagrams_in.load(Ordering::Relaxed),
             total_datagrams_out: self.total_datagrams_out.load(Ordering::Relaxed),
             detected_protocols: vec![],
+            frontend_protocols: ProtocolMetrics {
+                h1_active: self.frontend_h1_active.load(Ordering::Relaxed),
+                h1_total: self.frontend_h1_total.load(Ordering::Relaxed),
+                h2_active: self.frontend_h2_active.load(Ordering::Relaxed),
+                h2_total: self.frontend_h2_total.load(Ordering::Relaxed),
+                h3_active: self.frontend_h3_active.load(Ordering::Relaxed),
+                h3_total: self.frontend_h3_total.load(Ordering::Relaxed),
+                ws_active: self.frontend_ws_active.load(Ordering::Relaxed),
+                ws_total: self.frontend_ws_total.load(Ordering::Relaxed),
+                other_active: self.frontend_other_active.load(Ordering::Relaxed),
+                other_total: self.frontend_other_total.load(Ordering::Relaxed),
+            },
+            backend_protocols: ProtocolMetrics {
+                h1_active: self.backend_h1_active.load(Ordering::Relaxed),
+                h1_total: self.backend_h1_total.load(Ordering::Relaxed),
+                h2_active: self.backend_h2_active.load(Ordering::Relaxed),
+                h2_total: self.backend_h2_total.load(Ordering::Relaxed),
+                h3_active: self.backend_h3_active.load(Ordering::Relaxed),
+                h3_total: self.backend_h3_total.load(Ordering::Relaxed),
+                ws_active: self.backend_ws_active.load(Ordering::Relaxed),
+                ws_total: self.backend_ws_total.load(Ordering::Relaxed),
+                other_active: self.backend_other_active.load(Ordering::Relaxed),
+                other_total: self.backend_other_total.load(Ordering::Relaxed),
+            },
         }
     }
 }