"""Thread-safe WebSocket Manager for Gradio Frontend. This module provides a robust WebSocket connection that runs in a background thread with its own event loop, completely separated from Gradio's synchronous environment. Uses thread-safe queues for communication. Architecture: Gradio (Sync) ←→ Message Queues ←→ Background Thread (Async WebSocket) Usage: manager = WebSocketManager("ws://localhost:8000/ws/conversation/123") manager.start() # Send messages (sync) manager.send_message({"type": "start_conversation", ...}) # Get received messages (sync) messages = manager.get_messages() """ import asyncio import threading import time import json import queue import logging from typing import Dict, List, Optional from datetime import datetime from enum import Enum import websockets from websockets.exceptions import ConnectionClosed, WebSocketException # Setup logging logger = logging.getLogger(__name__) class ManagerState(Enum): """WebSocket manager states.""" STOPPED = "stopped" STARTING = "starting" CONNECTED = "connected" DISCONNECTED = "disconnected" ERROR = "error" class WebSocketManager: """Thread-safe WebSocket manager for Gradio frontend.""" def __init__(self, url: str, conversation_id: str, extra_headers: Optional[Dict[str, str]] = None): """Initialize WebSocket manager. Args: url: WebSocket server URL conversation_id: Unique conversation identifier extra_headers: Optional headers to send during the WebSocket handshake """ self.url = url self.conversation_id = conversation_id self.extra_headers = extra_headers # State management self.state = ManagerState.STOPPED self.last_error = None # Background thread and event loop self.thread = None self.loop = None self.websocket = None self._stop_event = threading.Event() # Thread-safe message queues self.outbound_queue = queue.Queue() # Messages to send self.inbound_queue = queue.Queue() # Received messages self.max_messages = 100 # Statistics self.messages_sent = 0 self.messages_received = 0 self.connection_time = None def start(self) -> bool: """Start the WebSocket manager in background thread. Returns: True if started successfully """ if self.thread and self.thread.is_alive(): logger.warning("WebSocket manager already running") return True try: self.state = ManagerState.STARTING self._stop_event.clear() # Start background thread self.thread = threading.Thread(target=self._run_websocket, daemon=True) self.thread.start() # Wait for connection (up to 10 seconds) start_time = time.time() while time.time() - start_time < 10: if self.state == ManagerState.CONNECTED: logger.info(f"WebSocket manager started successfully") return True elif self.state == ManagerState.ERROR: logger.error(f"WebSocket manager failed to start: {self.last_error}") return False time.sleep(0.1) logger.error("WebSocket manager startup timed out") self.state = ManagerState.ERROR self.last_error = "Startup timeout" return False except Exception as e: self.state = ManagerState.ERROR self.last_error = str(e) logger.error(f"Error starting WebSocket manager: {e}") return False def stop(self): """Stop the WebSocket manager.""" logger.info("Stopping WebSocket manager...") self._stop_event.set() if self.thread and self.thread.is_alive(): self.thread.join(timeout=5) self.state = ManagerState.STOPPED logger.info("WebSocket manager stopped") def send_message(self, message: Dict) -> bool: """Send message via WebSocket (thread-safe). Args: message: Message dictionary to send Returns: True if queued successfully """ if self.state != ManagerState.CONNECTED: logger.warning(f"Cannot send message - manager state: {self.state.value}") return False try: # Add metadata message.update({ "conversation_id": self.conversation_id, "timestamp": datetime.now().isoformat(), "client_id": f"gradio_{id(self)}" }) # Queue for background thread to send self.outbound_queue.put_nowait(message) logger.debug(f"Queued message: {message.get('type', 'unknown')}") return True except queue.Full: logger.error("Outbound message queue is full") return False except Exception as e: logger.error(f"Error queuing message: {e}") return False def get_messages(self) -> List[Dict]: """Get all received messages (thread-safe). Returns: List of received message dictionaries """ messages = [] try: while True: message = self.inbound_queue.get_nowait() messages.append(message) except queue.Empty: pass except Exception as e: logger.error(f"Error getting messages: {e}") return messages def get_conversation_messages(self) -> List[Dict]: """Get only conversation messages from received messages. Returns: List of conversation message dictionaries """ all_messages = self.get_messages() return [ msg for msg in all_messages if msg.get("type") == "conversation_message" ] def get_status(self) -> Dict: """Get current manager status. Returns: Status dictionary """ return { "state": self.state.value, "url": self.url, "conversation_id": self.conversation_id, "messages_sent": self.messages_sent, "messages_received": self.messages_received, "last_error": self.last_error, "connection_time": self.connection_time.isoformat() if self.connection_time else None, "thread_alive": self.thread.is_alive() if self.thread else False } def _run_websocket(self): """Run WebSocket in background thread with dedicated event loop.""" logger.info("Starting WebSocket background thread") try: # Create new event loop for this thread self.loop = asyncio.new_event_loop() asyncio.set_event_loop(self.loop) # Run the WebSocket connection self.loop.run_until_complete(self._websocket_main()) except Exception as e: logger.error(f"Error in WebSocket background thread: {e}") self.state = ManagerState.ERROR self.last_error = str(e) finally: if self.loop: self.loop.close() async def _websocket_main(self): """Main WebSocket connection and message handling loop.""" retry_count = 0 max_retries = 5 while not self._stop_event.is_set() and retry_count < max_retries: try: logger.info(f"Connecting to WebSocket: {self.url}") async with websockets.connect( self.url, extra_headers=self.extra_headers, ping_interval=20, ping_timeout=10 ) as websocket: self.websocket = websocket self.state = ManagerState.CONNECTED self.connection_time = datetime.now() retry_count = 0 # Reset on successful connection logger.info("WebSocket connected successfully") # Start message handling tasks send_task = asyncio.create_task(self._send_loop()) receive_task = asyncio.create_task(self._receive_loop()) # Wait until connection closes or stop requested done, pending = await asyncio.wait( [send_task, receive_task], return_when=asyncio.FIRST_COMPLETED ) # Cancel remaining tasks for task in pending: task.cancel() try: await task except asyncio.CancelledError: pass except (ConnectionClosed, WebSocketException) as e: logger.warning(f"WebSocket connection lost: {e}") self.state = ManagerState.DISCONNECTED if not self._stop_event.is_set(): retry_count += 1 retry_delay = min(2 ** retry_count, 30) # Exponential backoff logger.info(f"Reconnecting in {retry_delay}s (attempt {retry_count}/{max_retries})") await asyncio.sleep(retry_delay) except Exception as e: logger.error(f"Unexpected WebSocket error: {e}") self.state = ManagerState.ERROR self.last_error = str(e) break if retry_count >= max_retries: self.state = ManagerState.ERROR self.last_error = "Max reconnection attempts reached" self.websocket = None logger.info("WebSocket connection ended") async def _send_loop(self): """Send messages from outbound queue.""" while not self._stop_event.is_set(): try: # Check for messages to send (non-blocking) try: message = self.outbound_queue.get_nowait() await self.websocket.send(json.dumps(message)) self.messages_sent += 1 logger.debug(f"Sent message: {message.get('type', 'unknown')}") except queue.Empty: # No messages to send, sleep briefly await asyncio.sleep(0.1) except json.JSONEncodeError as e: logger.error(f"Error encoding message: {e}") except (ConnectionClosed, WebSocketException): logger.warning("WebSocket closed during send") break except Exception as e: logger.error(f"Error in send loop: {e}") break async def _receive_loop(self): """Receive messages and put in inbound queue.""" while not self._stop_event.is_set(): try: message_str = await self.websocket.recv() message = json.loads(message_str) # Add to inbound queue (with size limit) try: self.inbound_queue.put_nowait(message) self.messages_received += 1 logger.debug(f"Received message: {message.get('type', 'unknown')}") # Keep queue size manageable while self.inbound_queue.qsize() > self.max_messages: try: self.inbound_queue.get_nowait() except queue.Empty: break except queue.Full: logger.warning("Inbound message queue is full, dropping message") except (ConnectionClosed, WebSocketException): logger.warning("WebSocket closed during receive") break except json.JSONDecodeError as e: logger.error(f"Error decoding received message: {e}") except Exception as e: logger.error(f"Error in receive loop: {e}") break def __del__(self): """Cleanup on destruction.""" try: self.stop() except: pass