asyncio improvement

main.py

@@ -1,4 +1,5 @@
 import os
+import asyncio
 from fastapi import FastAPI, Request, Depends, HTTPException
 from starlette.middleware.sessions import SessionMiddleware 
 from starlette.staticfiles import StaticFiles 
@@ -23,6 +24,20 @@ BASE_DIR = os.path.dirname(os.path.abspath(__file__))
 STATIC_DIR = os.path.join(BASE_DIR, "static")
 TEMPLATES_DIR = os.path.join(BASE_DIR, "templates")
 
+@asynccontextmanager
+async def background_listener_startup(app: FastAPI):
+    """A non-blocking task to start listeners after the app has started."""
+    print("Background task: Starting listeners for all users...")
+    db = SessionLocal()
+    users = db.query(models.User).all()
+    db.close()
+    for user in users:
+        # Use try/except to ensure one failing listener doesn't stop others
+        try:
+            await app.state.listener_manager.start_listener_for_user(user, app.state.websocket_manager)
+        except Exception as e:
+            print(f"ERROR: Failed to start listener for user {user.id} ({user.username}): {e}")
+
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     # This code runs on startup
@@ -32,13 +47,8 @@ async def lifespan(app: FastAPI):
     models.Base.metadata.create_all(bind=engine)
     print("Application startup: Database tables created.")
 
-    # Start listeners for all existing users
-    db = SessionLocal()
-    users = db.query(models.User).all()
-    db.close()
-    for user in users:
-        await app.state.listener_manager.start_listener_for_user(user, app.state.websocket_manager)
-
+    # Decouple listener startup from the main application startup
+    asyncio.create_task(background_listener_startup(app))
     yield
     
     # This code runs on shutdown