import asyncio import logging import time from collections import deque from contextlib import asynccontextmanager from typing import Any, AsyncIterator, Deque, Dict, List, Optional, Type, Union from uuid import uuid4 from fastapi import WebSocketDisconnect from websockets.exceptions import ConnectionClosed from freqtrade.rpc.api_server.ws.proxy import WebSocketProxy from freqtrade.rpc.api_server.ws.serializer import ( HybridJSONWebSocketSerializer, WebSocketSerializer, ) from freqtrade.rpc.api_server.ws.types import WebSocketType from freqtrade.rpc.api_server.ws_schemas import WSMessageSchemaType logger = logging.getLogger(__name__) class WebSocketChannel: """ Object to help facilitate managing a websocket connection """ def __init__( self, websocket: WebSocketType, channel_id: Optional[str] = None, serializer_cls: Type[WebSocketSerializer] = HybridJSONWebSocketSerializer, send_throttle: float = 0.01, ): self.channel_id = channel_id if channel_id else uuid4().hex[:8] self._websocket = WebSocketProxy(websocket) # Internal event to signify a closed websocket self._closed = asyncio.Event() # The async tasks created for the channel self._channel_tasks: List[asyncio.Task] = [] # Deque for average send times self._send_times: Deque[float] = deque([], maxlen=10) # High limit defaults to 3 to start self._send_high_limit = 3 self._send_throttle = send_throttle # The subscribed message types self._subscriptions: List[str] = [] # Wrap the WebSocket in the Serializing class self._wrapped_ws = serializer_cls(self._websocket) def __repr__(self): return f"WebSocketChannel({self.channel_id}, {self.remote_addr})" @property def raw_websocket(self): return self._websocket.raw_websocket @property def remote_addr(self): return self._websocket.remote_addr @property def avg_send_time(self): return sum(self._send_times) / len(self._send_times) def _calc_send_limit(self): """ Calculate the send high limit for this channel """ # Only update if we have enough data if len(self._send_times) == self._send_times.maxlen: # At least 1s or twice the average of send times, with a # maximum of 3 seconds per message self._send_high_limit = min(max(self.avg_send_time * 2, 1), 3) async def send( self, message: Union[WSMessageSchemaType, Dict[str, Any]], use_timeout: bool = False ): """ Send a message on the wrapped websocket. If the sending takes too long, it will raise a TimeoutError and disconnect the connection. :param message: The message to send :param use_timeout: Enforce send high limit, defaults to False """ try: _ = time.time() # If the send times out, it will raise # a TimeoutError and bubble up to the # message_endpoint to close the connection await asyncio.wait_for( self._wrapped_ws.send(message), timeout=self._send_high_limit if use_timeout else None, ) total_time = time.time() - _ self._send_times.append(total_time) self._calc_send_limit() except asyncio.TimeoutError: logger.info(f"Connection for {self} timed out, disconnecting") raise # Explicitly give control back to event loop as # websockets.send does not # Also throttles how fast we send await asyncio.sleep(self._send_throttle) async def recv(self): """ Receive a message on the wrapped websocket """ return await self._wrapped_ws.recv() async def ping(self): """ Ping the websocket """ return await self._websocket.ping() async def accept(self): """ Accept the underlying websocket connection, if the connection has been closed before we can accept, just close the channel. """ try: return await self._websocket.accept() except RuntimeError: await self.close() async def close(self): """ Close the WebSocketChannel """ self._closed.set() try: await self._websocket.close() except RuntimeError: pass def is_closed(self) -> bool: """ Closed flag """ return self._closed.is_set() def set_subscriptions(self, subscriptions: List[str]) -> None: """ Set which subscriptions this channel is subscribed to :param subscriptions: List of subscriptions, List[str] """ self._subscriptions = subscriptions def subscribed_to(self, message_type: str) -> bool: """ Check if this channel is subscribed to the message_type :param message_type: The message type to check """ return message_type in self._subscriptions async def run_channel_tasks(self, *tasks, **kwargs): """ Create and await on the channel tasks unless an exception was raised, then cancel them all. :params *tasks: All coros or tasks to be run concurrently :param **kwargs: Any extra kwargs to pass to gather """ if not self.is_closed(): # Wrap the coros into tasks if they aren't already self._channel_tasks = [ task if isinstance(task, asyncio.Task) else asyncio.create_task(task) for task in tasks ] try: return await asyncio.gather(*self._channel_tasks, **kwargs) except Exception: # If an exception occurred, cancel the rest of the tasks await self.cancel_channel_tasks() async def cancel_channel_tasks(self): """ Cancel and wait on all channel tasks """ for task in self._channel_tasks: task.cancel() # Wait for tasks to finish cancelling try: await task except ( asyncio.CancelledError, asyncio.TimeoutError, WebSocketDisconnect, ConnectionClosed, RuntimeError, ): pass except Exception as e: logger.info(f"Encountered unknown exception: {e}", exc_info=e) self._channel_tasks = [] async def __aiter__(self): """ Generator for received messages """ # We can not catch any errors here as websocket.recv is # the first to catch any disconnects and bubble it up # so the connection is garbage collected right away while not self.is_closed(): yield await self.recv() @asynccontextmanager async def create_channel(websocket: WebSocketType, **kwargs) -> AsyncIterator[WebSocketChannel]: """ Context manager for safely opening and closing a WebSocketChannel """ channel = WebSocketChannel(websocket, **kwargs) try: await channel.accept() logger.info(f"Connected to channel - {channel}") yield channel finally: await channel.close() logger.info(f"Disconnected from channel - {channel}")