"""websockets bassd Socket Mode client * https://api.slack.com/apis/connections/socket * https://slack.dev/python-slack-sdk/socket-mode/ * https://pypi.org/project/websockets/ """ import asyncio import logging from asyncio import Future, Lock from logging import Logger from asyncio import Queue from typing import Union, Optional, List, Callable, Awaitable import websockets from websockets.exceptions import WebSocketException try: from websockets.asyncio.client import ClientConnection except ImportError: # To keep compatibility with websockets <14.x we use WebSocketClientProtocol # To keep compatibility with websockets 8.x, we use this import over .legacy.client from websockets import WebSocketClientProtocol as ClientConnection # type: ignore[no-redef, attr-defined] from slack_sdk.socket_mode.async_client import AsyncBaseSocketModeClient from slack_sdk.socket_mode.async_listeners import ( AsyncWebSocketMessageListener, AsyncSocketModeRequestListener, ) from slack_sdk.socket_mode.request import SocketModeRequest from slack_sdk.web.async_client import AsyncWebClient from ..logger.messages import debug_redacted_message_string def _session_closed(session: Optional[ClientConnection]) -> bool: if session is None: return True if hasattr(session, "closed"): # The session is a WebSocketClientProtocol instance return session.closed # WebSocket close code, defined in https://datatracker.ietf.org/doc/html/rfc6455.html#section-7.1.5 # None if the connection isn’t closed yet. return session.close_code is not None class SocketModeClient(AsyncBaseSocketModeClient): logger: Logger web_client: AsyncWebClient app_token: str wss_uri: Optional[str] # type: ignore[assignment] auto_reconnect_enabled: bool message_queue: Queue message_listeners: List[ Union[ AsyncWebSocketMessageListener, Callable[["AsyncBaseSocketModeClient", dict, Optional[str]], Awaitable[None]], ] ] socket_mode_request_listeners: List[ Union[ AsyncSocketModeRequestListener, Callable[["AsyncBaseSocketModeClient", SocketModeRequest], Awaitable[None]], ] ] message_receiver: Optional[Future] message_processor: Future ping_interval: float trace_enabled: bool current_session: Optional[ClientConnection] current_session_monitor: Optional[Future] default_auto_reconnect_enabled: bool closed: bool connect_operation_lock: Lock def __init__( self, app_token: str, logger: Optional[Logger] = None, web_client: Optional[AsyncWebClient] = None, auto_reconnect_enabled: bool = True, ping_interval: float = 10, trace_enabled: bool = False, ): """Socket Mode client Args: app_token: App-level token logger: Custom logger web_client: Web API client auto_reconnect_enabled: True if automatic reconnection is enabled (default: True) ping_interval: interval for ping-pong with Slack servers (seconds) trace_enabled: True if more verbose logs to see what's happening under the hood """ self.app_token = app_token self.logger = logger or logging.getLogger(__name__) self.web_client = web_client or AsyncWebClient() self.closed = False self.connect_operation_lock = Lock() self.default_auto_reconnect_enabled = auto_reconnect_enabled self.auto_reconnect_enabled = self.default_auto_reconnect_enabled self.ping_interval = ping_interval self.trace_enabled = trace_enabled self.wss_uri = None self.message_queue = Queue() self.message_listeners = [] self.socket_mode_request_listeners = [] self.current_session = None self.current_session_monitor = None self.message_receiver = None self.message_processor = asyncio.ensure_future(self.process_messages()) async def monitor_current_session(self) -> None: # In the asyncio runtime, accessing a shared object (self.current_session here) from # multiple tasks can cause race conditions and errors. # To avoid such, we access only the session that is active when this loop starts. session: ClientConnection = self.current_session # type: ignore[assignment] session_id: str = await self.session_id() if self.logger.level <= logging.DEBUG: self.logger.debug(f"A new monitor_current_session() execution loop for {session_id} started") try: while not self.closed: if session != self.current_session: if self.logger.level <= logging.DEBUG: self.logger.debug(f"The monitor_current_session task for {session_id} is now cancelled") break await asyncio.sleep(self.ping_interval) try: if self.auto_reconnect_enabled and _session_closed(session=session): self.logger.info(f"The session ({session_id}) seems to be already closed. Reconnecting...") await self.connect_to_new_endpoint() except Exception as e: self.logger.error( "Failed to check the current session or reconnect to the server " f"(error: {type(e).__name__}, message: {e}, session: {session_id})" ) except asyncio.CancelledError: if self.logger.level <= logging.DEBUG: self.logger.debug(f"The monitor_current_session task for {session_id} is now cancelled") raise async def receive_messages(self) -> None: # In the asyncio runtime, accessing a shared object (self.current_session here) from # multiple tasks can cause race conditions and errors. # To avoid such, we access only the session that is active when this loop starts. session: ClientConnection = self.current_session # type: ignore[assignment] session_id: str = await self.session_id() consecutive_error_count = 0 if self.logger.level <= logging.DEBUG: self.logger.debug(f"A new receive_messages() execution loop with {session_id} started") try: while not self.closed: if session != self.current_session: if self.logger.level <= logging.DEBUG: self.logger.debug(f"The running receive_messages task for {session_id} is now cancelled") break try: message = await session.recv() if message is not None: if isinstance(message, bytes): message = message.decode("utf-8") if self.logger.level <= logging.DEBUG: self.logger.debug( f"Received message: {debug_redacted_message_string(message)}, session: {session_id}" ) await self.enqueue_message(message) consecutive_error_count = 0 except Exception as e: consecutive_error_count += 1 self.logger.error( f"Failed to receive or enqueue a message: {type(e).__name__}, error: {e}, session: {session_id}" ) if isinstance(e, websockets.ConnectionClosedError): await asyncio.sleep(self.ping_interval) else: await asyncio.sleep(consecutive_error_count) except asyncio.CancelledError: if self.logger.level <= logging.DEBUG: self.logger.debug(f"The running receive_messages task for {session_id} is now cancelled") raise async def is_connected(self) -> bool: return not self.closed and not _session_closed(self.current_session) async def session_id(self) -> str: return self.build_session_id(self.current_session) # type: ignore[arg-type] async def connect(self): if self.wss_uri is None: self.wss_uri = await self.issue_new_wss_url() old_session: Optional[ClientConnection] = None if self.current_session is None else self.current_session # NOTE: websockets does not support proxy settings self.current_session = await websockets.connect( uri=self.wss_uri, ping_interval=self.ping_interval, ) session_id = await self.session_id() self.auto_reconnect_enabled = self.default_auto_reconnect_enabled self.logger.info(f"A new session ({session_id}) has been established") if self.current_session_monitor is not None: self.current_session_monitor.cancel() self.current_session_monitor = asyncio.ensure_future(self.monitor_current_session()) if self.logger.level <= logging.DEBUG: self.logger.debug(f"A new monitor_current_session() executor has been recreated for {session_id}") if self.message_receiver is not None: self.message_receiver.cancel() self.message_receiver = asyncio.ensure_future(self.receive_messages()) if self.logger.level <= logging.DEBUG: self.logger.debug(f"A new receive_messages() executor has been recreated for {session_id}") if old_session is not None: await old_session.close() old_session_id = self.build_session_id(old_session) self.logger.info(f"The old session ({old_session_id}) has been abandoned") async def disconnect(self): if self.current_session is not None: await self.current_session.close() async def send_message(self, message: str): session = self.current_session session_id = self.build_session_id(session) # type: ignore[arg-type] if self.logger.level <= logging.DEBUG: self.logger.debug(f"Sending a message: {message}, session: {session_id}") try: await session.send(message) # type: ignore[union-attr] except WebSocketException as e: # We rarely get this exception while replacing the underlying WebSocket connections. # We can do one more try here as the self.current_session should be ready now. if self.logger.level <= logging.DEBUG: self.logger.debug( f"Failed to send a message (error: {e}, message: {message}, session: {session_id})" " as the underlying connection was replaced. Retrying the same request only one time..." ) # Although acquiring self.connect_operation_lock also for the first method call is the safest way, # we avoid synchronizing a lot for better performance. That's why we are doing a retry here. try: if await self.is_connected(): await self.current_session.send(message) # type: ignore[union-attr] else: self.logger.warning(f"The current session ({session_id}) is no longer active. Failed to send a message") raise e finally: if self.connect_operation_lock.locked() is True: self.connect_operation_lock.release() async def close(self): self.closed = True self.auto_reconnect_enabled = False await self.disconnect() self.message_processor.cancel() if self.current_session_monitor is not None: self.current_session_monitor.cancel() if self.message_receiver is not None: self.message_receiver.cancel() @classmethod def build_session_id(cls, session: ClientConnection) -> str: if session is None: return "" return "s_" + str(hash(session))