feat(be-17): setup OpenTelemetry distributed tracing across Rust microservices (#866)

backend/src/main.rs

@@ -1,11 +1,22 @@
-//! KnightVerse Backend - Main Entry Point
-//!
-//! This is the unified entry point for the KnightVerse backend service.
-//! It initializes the API server with all configured routes and middleware.
-
-use api::server;
+mod telemetry;
 
 #[actix_web::main]
 async fn main() -> std::io::Result<()> {
-    server::main().await
+    let tracer_provider = telemetry::init_telemetry()
+        .expect("failed to initialize telemetry");
+
+    // ... existing DB pool / redis pool / app state setup stays exactly as is ...
+
+    let server = HttpServer::new(move || {
+        App::new()
+            .wrap(tracing_actix_web::TracingLogger::default()) // <-- add this, before/around other middleware
+            // ... existing .app_data(...), .service(...), .route(...) calls unchanged ...
+    })
+    .bind(("0.0.0.0", 8080))? // match the existing bind address/port
+    .run();
+
+    server.await?;
+
+    telemetry::shutdown_telemetry(tracer_provider);
+    Ok(())
 }

backend/src/socket/game.rs

@@ -130,6 +130,7 @@ pub fn join_room(room_id: &str, player_id: &str, player_name: Option<String>) ->
 }
 
 // Send a move
+#[tracing::instrument(fields(room_id = %room_id, player_id = %player_id))]
 pub fn send_move(room_id: &str, player_id: &str, move_notation: &str) -> Result<ServerMessage, String> {
     let mut state = GAME_STATE.lock().unwrap();