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Add Twisted Protocol based UDP endpoint listener
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,223 +1,56 @@ | ||
| import errno | ||
| from select import select | ||
| import socket | ||
| import sys | ||
| import threading | ||
| from time import time | ||
|
|
||
| from ..endpoint import DataTooBigException, Endpoint, EndpointClosedException, IllegalDestination | ||
|
|
||
| if sys.platform == 'win32': | ||
| SOCKET_BLOCK_ERRORCODE = 10035 # WSAEWOULDBLOCK | ||
| else: | ||
| SOCKET_BLOCK_ERRORCODE = errno.EWOULDBLOCK | ||
| from twisted.internet import protocol, reactor, error | ||
| from ..endpoint import Endpoint, EndpointClosedException | ||
|
|
||
| UDP_MAX_SIZE = 2 ** 16 - 60 | ||
|
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|
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| class UDPEndpoint(Endpoint): | ||
| """ | ||
| UDP implementation for sending messages over the Internet. | ||
| """ | ||
| class UDPEndpoint(Endpoint, protocol.DatagramProtocol): | ||
|
|
||
| def __init__(self, port, ip="0.0.0.0"): | ||
| """ | ||
| Bind an interface to the WWW on a certain port (and IP). | ||
| :param port: the port to use | ||
| :type port: int | ||
| :param ip: the interface to bind to | ||
| :type ip: string | ||
| """ | ||
| super(UDPEndpoint, self).__init__() | ||
|
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||
| self._port = port | ||
| self._ip = ip | ||
|
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| self._thread = None | ||
| self._socket = None | ||
|
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| self._sendqueue_lock = threading.RLock() | ||
| self._sendqueue = [] | ||
|
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| self._running = False | ||
| self._listening_port = False | ||
|
|
||
| def assert_open(self): | ||
| """ | ||
| Check if the underlying socket is open, or raise an exception. | ||
| :raises: EndpointClosedException if the socket is closed | ||
| """ | ||
| if not self.is_open(): | ||
| raise EndpointClosedException(self) | ||
|
|
||
| def is_open(self): | ||
| """ | ||
| Check if the underlying socket is open. | ||
| """ | ||
| return self._socket and self._running | ||
|
|
||
| def get_address(self): | ||
| """ | ||
| Get the address for this Endpoint. | ||
| """ | ||
| self.assert_open() | ||
| return self._socket.getsockname() | ||
| def datagramReceived(self, datagram, addr): | ||
| self.notify_listeners((addr, datagram)) | ||
|
|
||
| def send(self, socket_address, packet): | ||
| """ | ||
| Send a UDP packet to a socket_address. | ||
| :param socket_address: the socket_address to send the packet to | ||
| :param packet: the packet to send to the socket_address | ||
| :return: whether sending was successful | ||
| """ | ||
| self.assert_open() | ||
|
|
||
| if len(packet) > UDP_MAX_SIZE: | ||
| raise DataTooBigException(len(packet), UDP_MAX_SIZE) | ||
| if socket_address == ('0.0.0.0', 0): | ||
| raise IllegalDestination() | ||
|
|
||
| try: | ||
| self._socket.sendto(packet, socket_address) | ||
| except socket.error: | ||
| with self._sendqueue_lock: | ||
| did_have_senqueue = bool(self._sendqueue) | ||
| self._sendqueue.append((time(), socket_address, packet)) | ||
|
|
||
| # If we did not have a sendqueue, then we need to call process_sendqueue in order send these messages | ||
| if not did_have_senqueue: | ||
| self._process_sendqueue() | ||
|
|
||
| return True | ||
| self.transport.write(packet, socket_address) | ||
|
|
||
| def open(self): | ||
| """ | ||
| Open this Endpoint for sending and receiving packets. | ||
| """ | ||
| for _ in xrange(10000): | ||
| try: | ||
| self._listening_port = reactor.listenUDP(self._port, self, self._ip, UDP_MAX_SIZE) | ||
| self._logger.debug("Listening at %d", self._port) | ||
| self._socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) | ||
| self._socket.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, 870400) | ||
| self._socket.bind((self._ip, self._port)) | ||
| self._socket.setblocking(0) | ||
|
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||
| self._port = self._socket.getsockname()[1] | ||
| except socket.error: | ||
| break | ||
| except error.CannotListenError: | ||
| self._logger.debug("Listening failed at %d", self._port) | ||
| self._port += 1 | ||
| continue | ||
| break | ||
|
|
||
| self._running = True | ||
| self._thread = threading.Thread(name="UDPEndpoint", target=self._loop) | ||
| self._thread.daemon = True | ||
| self._thread.start() | ||
| return True | ||
|
|
||
| def close(self, timeout=10.0): | ||
| """ | ||
| Close this Endpoint for sending and receiving. | ||
| :param timeout: the maximum amount of time to wait for the socket to close | ||
| :return: whether closing occurred naturally | ||
| """ | ||
| self._running = False | ||
| result = True | ||
|
|
||
| if timeout > 0.0: | ||
| self._thread.join(timeout) | ||
|
|
||
| if self._thread.is_alive(): | ||
| self._logger.error("the endpoint thread is still running (after waiting %f seconds)", timeout) | ||
| result = False | ||
|
|
||
| else: | ||
| if self._thread.is_alive(): | ||
| self._logger.error("the endpoint thread is still running " | ||
| "(use timeout > 0.0 to ensure the thread stops)") | ||
| result = False | ||
|
|
||
| try: | ||
| self._socket.close() | ||
| except socket.error as exception: | ||
| self._logger.exception("%s", exception) | ||
| result = False | ||
| def assert_open(self): | ||
| if not self._running: | ||
| raise EndpointClosedException(self) | ||
|
|
||
| return result | ||
| def close(self): | ||
| self._running = False | ||
| return self._listening_port.stopListening() | ||
|
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||
| def _loop(self): | ||
| def get_address(self): | ||
| """ | ||
| The loop handling sending and receiving messages over this Endpoint. | ||
| Get the address for this Endpoint. | ||
| """ | ||
| self.assert_open() | ||
| return (self._listening_port.getHost().host, | ||
| self._listening_port.getHost().port) | ||
|
|
||
| recvfrom = self._socket.recvfrom | ||
| socket_list = [self._socket.fileno()] | ||
|
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| prev_sendqueue = 0 | ||
| while self._running: | ||
| # This is a tricky, if we are running on the DAS4 whenever a socket is ready for writing all processes of | ||
| # this node will try to write. Therefore, we have to limit the frequency of trying to write a bit. | ||
| if self._sendqueue and (time() - prev_sendqueue) > 0.1: | ||
| read_list, write_list, _ = select(socket_list, socket_list, [], 0.1) | ||
| else: | ||
| read_list, write_list, _ = select(socket_list, [], [], 0.1) | ||
|
|
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| # Furthermore, if we are allowed to send, process sendqueue immediately | ||
| if write_list: | ||
| self._process_sendqueue() | ||
| prev_sendqueue = time() | ||
|
|
||
| if read_list: | ||
| packets = [] | ||
| try: | ||
| while True: | ||
| (data, sock_addr) = recvfrom(65535) | ||
| if data: | ||
| packets.append((sock_addr, data)) | ||
| else: | ||
| break | ||
|
|
||
| except socket.error as e: | ||
| if e.errno != errno.EAGAIN: | ||
| self._logger.debug('socket error: %s' % repr(e)) | ||
|
|
||
| finally: | ||
| if packets: | ||
| for packet in packets: | ||
| self.notify_listeners(packet) | ||
|
|
||
| def _process_sendqueue(self): | ||
| def is_open(self): | ||
| """ | ||
| Send any outstanding/previously undeliverable messages. | ||
| Check if the underlying socket is open. | ||
| """ | ||
| self.assert_open() | ||
|
|
||
| with self._sendqueue_lock: | ||
| if self._sendqueue: | ||
| index = 0 | ||
| NUM_PACKETS = min(max(50, len(self._sendqueue) / 10), len(self._sendqueue)) | ||
| self._logger.debug("%d left in sendqueue, trying to send %d packets", | ||
| len(self._sendqueue), NUM_PACKETS) | ||
|
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| allowed_timestamp = time() - 300 | ||
|
|
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| for i in xrange(NUM_PACKETS): | ||
| queued_at, sock_addr, data = self._sendqueue[i] | ||
| if queued_at > allowed_timestamp: | ||
| try: | ||
| self._socket.sendto(data, sock_addr) | ||
| index += 1 | ||
| except socket.error as e: | ||
| if e[0] != SOCKET_BLOCK_ERRORCODE: | ||
| self._logger.warning("could not send %d to %s (%d in sendqueue)", | ||
| len(data), sock_addr, len(self._sendqueue)) | ||
| break | ||
| else: | ||
| index += 1 | ||
|
|
||
| self._sendqueue = self._sendqueue[index:] | ||
| if self._sendqueue: | ||
| self._logger.debug("%d left in sendqueue", len(self._sendqueue)) | ||
| return self._listening_port and self._running |
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