fix: use synchronous FastAPI webhook to prevent Cloud Run from freezing the bot during CPU throttling

Author: rozen03

main.py

@@ -5,9 +5,11 @@
 import traceback
 from telegram.constants import ParseMode
 from telegram.ext import Application, CommandHandler, CallbackQueryHandler, MessageHandler, filters
+from contextlib import asynccontextmanager
+from fastapi import FastAPI, Request, Response
+import uvicorn
 
 from bot_logic import COMMANDS, button
-from models import init_db
 from tg_ids import ROZEN_CHATID
 
 async def error_handler(update, context):
@@ -54,16 +56,51 @@ async def post_init(application: Application):
     except Exception as e:
         logging.getLogger("DCUBABOT").error(f"Failed to set bot commands: {e}")
 
+# Instancia global de la aplicación de Telegram
+application = Application.builder().token(os.environ["TELEGRAM_BOT_TOKEN"]).post_init(post_init).build()
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    # Setup de la aplicación de Telegram al arrancar FastAPI
+    await application.initialize()
+    await application.start()
+    
+    webhook_url = os.environ["WEBHOOK_URL"]
+    token = os.environ["TELEGRAM_BOT_TOKEN"]
+    url = f'{webhook_url.rstrip("/")}/{token}'
+    await application.bot.set_webhook(url=url)
+    
+    yield
+    
+    # Shutdown
+    await application.stop()
+    await application.shutdown()
+
+app = FastAPI(lifespan=lifespan)
+
+@app.post("/{token}")
+async def telegram_webhook(token: str, request: Request):
+    if token != os.environ["TELEGRAM_BOT_TOKEN"]:
+        return Response(status_code=403)
+        
+    try:
+        data = await request.json()
+        update = telegram.Update.de_json(data=data, bot=application.bot)
+        # Await the processing SYNCHRONOUSLY before returning 200 OK
+        # This prevents Cloud Run from throttling the CPU while the bot is doing work
+        await application.process_update(update)
+    except Exception as e:
+        logging.error(f"Failed to process update: {e}")
+        
+    return Response(status_code=200)
+
 def main():
     """Start the bot."""
     logging.basicConfig(
         level=logging.INFO,
         format='[%(asctime)s] - [%(name)s] - [%(levelname)s] - %(message)s',
     )
 
-
-    application = Application.builder().token(os.environ["TELEGRAM_BOT_TOKEN"]).post_init(post_init).build()
-
     application.add_error_handler(error_handler)
 
     # Add the logging middleware handler with a high priority
@@ -74,15 +111,9 @@ def main():
 
     application.add_handler(CallbackQueryHandler(button))
 
-    webhook_url = os.environ["WEBHOOK_URL"]
-    
-    # Start the Bot
-    application.run_webhook(
-        listen="0.0.0.0",
-        port=int(os.environ.get("PORT", 8080)),
-        url_path=os.environ["TELEGRAM_BOT_TOKEN"],
-        webhook_url=f'{webhook_url.rstrip("/")}/{os.environ["TELEGRAM_BOT_TOKEN"]}',
-    )
+    # Run the FastAPI app via uvicorn
+    port = int(os.environ.get("PORT", 8080))
+    uvicorn.run(app, host="0.0.0.0", port=port)
 
 if __name__ == "__main__":
     main()