# This has to be done first as Twisted is import-order-sensitive with reactors import asyncio # isort:skip import os # isort:skip import sys # isort:skip import warnings # isort:skip from concurrent.futures import ThreadPoolExecutor # isort:skip from twisted.internet import asyncioreactor # isort:skip twisted_loop = asyncio.new_event_loop() if "ASGI_THREADS" in os.environ: twisted_loop.set_default_executor( ThreadPoolExecutor(max_workers=int(os.environ["ASGI_THREADS"])) ) current_reactor = sys.modules.get("twisted.internet.reactor", None) if current_reactor is not None: if not isinstance(current_reactor, asyncioreactor.AsyncioSelectorReactor): warnings.warn( "Something has already installed a non-asyncio Twisted reactor. Attempting to uninstall it; " + "you can fix this warning by importing daphne.server early in your codebase or " + "finding the package that imports Twisted and importing it later on.", UserWarning, stacklevel=2, ) del sys.modules["twisted.internet.reactor"] asyncioreactor.install(twisted_loop) else: asyncioreactor.install(twisted_loop) import logging import time from concurrent.futures import CancelledError from functools import partial from twisted.internet import defer, reactor from twisted.internet.endpoints import serverFromString from twisted.logger import STDLibLogObserver, globalLogBeginner from twisted.web import http from .http_protocol import HTTPFactory from .ws_protocol import WebSocketFactory logger = logging.getLogger(__name__) class Server: def __init__( self, application, endpoints=None, signal_handlers=True, action_logger=None, http_timeout=None, request_buffer_size=8192, websocket_timeout=86400, websocket_connect_timeout=20, ping_interval=20, ping_timeout=30, root_path="", proxy_forwarded_address_header=None, proxy_forwarded_port_header=None, proxy_forwarded_proto_header=None, verbosity=1, websocket_handshake_timeout=5, application_close_timeout=10, ready_callable=None, server_name="daphne", ): self.application = application self.endpoints = endpoints or [] self.listeners = [] self.listening_addresses = [] self.signal_handlers = signal_handlers self.action_logger = action_logger self.http_timeout = http_timeout self.ping_interval = ping_interval self.ping_timeout = ping_timeout self.request_buffer_size = request_buffer_size self.proxy_forwarded_address_header = proxy_forwarded_address_header self.proxy_forwarded_port_header = proxy_forwarded_port_header self.proxy_forwarded_proto_header = proxy_forwarded_proto_header self.websocket_timeout = websocket_timeout self.websocket_connect_timeout = websocket_connect_timeout self.websocket_handshake_timeout = websocket_handshake_timeout self.application_close_timeout = application_close_timeout self.root_path = root_path self.verbosity = verbosity self.abort_start = False self.ready_callable = ready_callable self.server_name = server_name # Check our construction is actually sensible if not self.endpoints: logger.error("No endpoints. This server will not listen on anything.") sys.exit(1) def run(self): # A dict of protocol: {"application_instance":, "connected":, "disconnected":} dicts self.connections = {} # Make the factory self.http_factory = HTTPFactory(self) self.ws_factory = WebSocketFactory(self, server=self.server_name) self.ws_factory.setProtocolOptions( autoPingTimeout=self.ping_timeout, allowNullOrigin=True, openHandshakeTimeout=self.websocket_handshake_timeout, ) if self.verbosity <= 1: # Redirect the Twisted log to nowhere globalLogBeginner.beginLoggingTo( [lambda _: None], redirectStandardIO=False, discardBuffer=True ) else: globalLogBeginner.beginLoggingTo([STDLibLogObserver(__name__)]) # Detect what Twisted features are enabled if http.H2_ENABLED: logger.info("HTTP/2 support enabled") else: logger.info( "HTTP/2 support not enabled (install the http2 and tls Twisted extras)" ) # Kick off the timeout loop reactor.callLater(1, self.application_checker) reactor.callLater(2, self.timeout_checker) for socket_description in self.endpoints: logger.info("Configuring endpoint %s", socket_description) ep = serverFromString(reactor, str(socket_description)) listener = ep.listen(self.http_factory) listener.addCallback(self.listen_success) listener.addErrback(self.listen_error) self.listeners.append(listener) # Set the asyncio reactor's event loop as global # TODO: Should we instead pass the global one into the reactor? asyncio.set_event_loop(reactor._asyncioEventloop) # Verbosity 3 turns on asyncio debug to find those blocking yields if self.verbosity >= 3: asyncio.get_event_loop().set_debug(True) reactor.addSystemEventTrigger("before", "shutdown", self.kill_all_applications) if not self.abort_start: # Trigger the ready flag if we had one if self.ready_callable: self.ready_callable() # Run the reactor reactor.run(installSignalHandlers=self.signal_handlers) def listen_success(self, port): """ Called when a listen succeeds so we can store port details (if there are any) """ if hasattr(port, "getHost"): host = port.getHost() if hasattr(host, "host") and hasattr(host, "port"): self.listening_addresses.append((host.host, host.port)) logger.info( "Listening on TCP address %s:%s", port.getHost().host, port.getHost().port, ) def listen_error(self, failure): logger.critical("Listen failure: %s", failure.getErrorMessage()) self.stop() def stop(self): """ Force-stops the server. """ if reactor.running: reactor.stop() else: self.abort_start = True ### Protocol handling def protocol_connected(self, protocol): """ Adds a protocol as a current connection. """ if protocol in self.connections: raise RuntimeError("Protocol %r was added to main list twice!" % protocol) self.connections[protocol] = {"connected": time.time()} def protocol_disconnected(self, protocol): # Set its disconnected time (the loops will come and clean it up) # Do not set it if it is already set. Overwriting it might # cause it to never be cleaned up. # See https://github.com/django/channels/issues/1181 if "disconnected" not in self.connections[protocol]: self.connections[protocol]["disconnected"] = time.time() ### Internal event/message handling def create_application(self, protocol, scope): """ Creates a new application instance that fronts a Protocol instance for one of our supported protocols. Pass it the protocol, and it will work out the type, supply appropriate callables, and return you the application's input queue """ # Make sure the protocol has not had another application made for it assert "application_instance" not in self.connections[protocol] # Make an instance of the application input_queue = asyncio.Queue() scope.setdefault("asgi", {"version": "3.0"}) application_instance = self.application( scope=scope, receive=input_queue.get, send=partial(self.handle_reply, protocol), ) # Run it, and stash the future for later checking if protocol not in self.connections: return None self.connections[protocol]["application_instance"] = asyncio.ensure_future( application_instance, loop=asyncio.get_event_loop(), ) return input_queue async def handle_reply(self, protocol, message): """ Coroutine that jumps the reply message from asyncio to Twisted """ # Don't do anything if the connection is closed or does not exist if protocol not in self.connections or self.connections[protocol].get( "disconnected", None ): return try: self.check_headers_type(message) except ValueError: # Ensure to send SOME reply. protocol.basic_error(500, b"Server Error", "Server Error") raise # Let the protocol handle it protocol.handle_reply(message) @staticmethod def check_headers_type(message): if not message["type"] == "http.response.start": return for k, v in message.get("headers", []): if not isinstance(k, bytes): raise ValueError( "Header name '{}' expected to be `bytes`, but got `{}`".format( k, type(k) ) ) if not isinstance(v, bytes): raise ValueError( "Header value '{}' expected to be `bytes`, but got `{}`".format( v, type(v) ) ) ### Utility def application_checker(self): """ Goes through the set of current application Futures and cleans up any that are done/prints exceptions for any that errored. """ for protocol, details in list(self.connections.items()): disconnected = details.get("disconnected", None) application_instance = details.get("application_instance", None) # First, see if the protocol disconnected and the app has taken # too long to close up if ( disconnected and time.time() - disconnected > self.application_close_timeout ): if application_instance and not application_instance.done(): logger.warning( "Application instance %r for connection %s took too long to shut down and was killed.", application_instance, repr(protocol), ) application_instance.cancel() # Then see if the app is done and we should reap it if application_instance and application_instance.done(): try: exception = application_instance.exception() except (CancelledError, asyncio.CancelledError): # Future cancellation. We can ignore this. pass else: if exception: if isinstance(exception, KeyboardInterrupt): # Protocol is asking the server to exit (likely during test) self.stop() else: logger.error( "Exception inside application: %s", exception, exc_info=exception, ) if not disconnected: protocol.handle_exception(exception) del self.connections[protocol]["application_instance"] application_instance = None # Check to see if protocol is closed and app is closed so we can remove it if not application_instance and disconnected: del self.connections[protocol] reactor.callLater(1, self.application_checker) def kill_all_applications(self): """ Kills all application coroutines before reactor exit. """ # Send cancel to all coroutines wait_for = [] for details in self.connections.values(): application_instance = details["application_instance"] if not application_instance.done(): application_instance.cancel() wait_for.append(application_instance) logger.info("Killed %i pending application instances", len(wait_for)) # Make Twisted wait until they're all dead wait_deferred = defer.Deferred.fromFuture(asyncio.gather(*wait_for)) wait_deferred.addErrback(lambda x: None) return wait_deferred def timeout_checker(self): """ Called periodically to enforce timeout rules on all connections. Also checks pings at the same time. """ for protocol in list(self.connections.keys()): protocol.check_timeouts() reactor.callLater(2, self.timeout_checker) def log_action(self, protocol, action, details): """ Dispatches to any registered action logger, if there is one. """ if self.action_logger: self.action_logger(protocol, action, details)