|
| 1 | +import re |
| 2 | +import socket |
| 3 | +import logging |
| 4 | +import eventlet |
| 5 | + |
| 6 | +from tools import * |
| 7 | + |
| 8 | +log = configure_logging('Duplex') |
| 9 | + |
| 10 | + |
| 11 | +class DuplexAPI: |
| 12 | + def __new__(cls): |
| 13 | + eventlet_routine() |
| 14 | + return object.__new__(cls) |
| 15 | + |
| 16 | + def __init__(self): |
| 17 | + self._job = None |
| 18 | + self._sock = None |
| 19 | + self._regex = None |
| 20 | + self._running = None |
| 21 | + self._last_exc = None |
| 22 | + self._buffer = bytearray() |
| 23 | + |
| 24 | + self._pool = eventlet.GreenPool() |
| 25 | + self._recv_queue = eventlet.Queue() |
| 26 | + self._send_queue = eventlet.Queue() |
| 27 | + |
| 28 | + if type(self) is DuplexAPI: |
| 29 | + raise NotImplementedError("DuplexAPI is not meant to be instanciated, use the Duplex class.") |
| 30 | + |
| 31 | + def _pack_msg(self, msg: bytes): |
| 32 | + return b'%START%' + msg + b'%STOP%' |
| 33 | + |
| 34 | + def _unpack_msg(self, data: bytes): |
| 35 | + if self._regex is None: |
| 36 | + self._regex = re.compile(b'%START%(.*?)%STOP%', flags=re.DOTALL) |
| 37 | + |
| 38 | + messages = self._regex.findall(data) |
| 39 | + remainder = self._regex.sub(b'', data) |
| 40 | + return messages, remainder |
| 41 | + |
| 42 | + def _reset_buffer(self, data: bytes): |
| 43 | + self._buffer.clear() |
| 44 | + self._buffer.extend(data) |
| 45 | + |
| 46 | + def _recv_to_buffer(self): |
| 47 | + while True: |
| 48 | + try: |
| 49 | + chunk = self._sock.recv(4096) |
| 50 | + except socket.error: |
| 51 | + # Non-blocking socket, no data available. |
| 52 | + break |
| 53 | + |
| 54 | + if chunk: |
| 55 | + self._buffer.extend(chunk) |
| 56 | + else: |
| 57 | + self._notify_disconnected() |
| 58 | + break |
| 59 | + |
| 60 | + def _recv_msg(self): |
| 61 | + self._recv_to_buffer() |
| 62 | + messages, remainder = self._unpack_msg(self._buffer) |
| 63 | + self._reset_buffer(remainder) |
| 64 | + return messages |
| 65 | + |
| 66 | + def _send_msg(self, msg: bytes): |
| 67 | + packet = self._pack_msg(msg) |
| 68 | + self._sock.sendall(packet) |
| 69 | + |
| 70 | + def _send_items_in_queue(self): |
| 71 | + if not self._send_queue.empty(): |
| 72 | + try: |
| 73 | + packet = self._send_queue.get(timeout=2) |
| 74 | + except eventlet.queue.Empty: |
| 75 | + log.warning("Couldn't fetch item from queue.") |
| 76 | + else: |
| 77 | + self._send_msg(packet) |
| 78 | + |
| 79 | + def _receive_and_put_in_queue(self): |
| 80 | + for msg in self._recv_msg(): |
| 81 | + try: |
| 82 | + self._recv_queue.put(msg, timeout=2) |
| 83 | + except eventlet.queue.Full: |
| 84 | + log.warning(f"Couldn't put item in queue.") |
| 85 | + |
| 86 | + def _loop_running(self): |
| 87 | + return self._running is True |
| 88 | + |
| 89 | + def _stop_loop(self): |
| 90 | + self._running = False |
| 91 | + |
| 92 | + def _exchange_messages(self): |
| 93 | + while self._loop_running(): |
| 94 | + self._send_items_in_queue() |
| 95 | + self._receive_and_put_in_queue() |
| 96 | + eventlet.sleep() |
| 97 | + |
| 98 | + def _notify_disconnected(self): |
| 99 | + log.debug("Peer disconnected.") |
| 100 | + self.stop(exception=socket.error("Other side disconnected.")) |
| 101 | + |
| 102 | + def _kill_job(self): |
| 103 | + if self._job is not None: |
| 104 | + self._job.kill() |
| 105 | + if self._sock is not None: |
| 106 | + self._sock.close() |
| 107 | + |
| 108 | + def _handle_exception(self, raise_exc: bool = True): |
| 109 | + if self._last_exc is None: |
| 110 | + return |
| 111 | + |
| 112 | + last_exc = self._last_exc |
| 113 | + |
| 114 | + if raise_exc: |
| 115 | + self._last_exc = None |
| 116 | + raise last_exc |
| 117 | + else: |
| 118 | + log.exception("Duplex stopped due to an exception.", exc_info=last_exc) |
| 119 | + |
| 120 | + def _get(self, block: bool = True, timeout: int | None = None): |
| 121 | + msg = self._recv_queue.get(block=block, timeout=timeout) |
| 122 | + return msg |
| 123 | + |
| 124 | + def _get_safe(self): |
| 125 | + while True: |
| 126 | + try: |
| 127 | + msg = self._get(block=False, timeout=1) |
| 128 | + return msg |
| 129 | + except eventlet.queue.Empty: |
| 130 | + pass |
| 131 | + |
| 132 | + if not self._loop_running(): |
| 133 | + log.error("Can't receive message, duplex interrupted.") |
| 134 | + return b'' |
| 135 | + |
| 136 | + eventlet.sleep() |
| 137 | + |
| 138 | + def _put(self, *args, **kwargs): |
| 139 | + self._send_queue.put(*args, **kwargs) |
| 140 | + |
| 141 | + def __del__(self): |
| 142 | + self.close(raise_exc=False) |
| 143 | + |
| 144 | + |
| 145 | +class Duplex(DuplexAPI): |
| 146 | + |
| 147 | + def listen(self, port: int, *, host: str): |
| 148 | + """Wait for a connection on the given port and host.""" |
| 149 | + server = socket.create_server((host, port)) |
| 150 | + server.listen(0) |
| 151 | + log.info(f"Listening on %s:%d.", host, port) |
| 152 | + |
| 153 | + self._sock, peer = server.accept() |
| 154 | + self._sock.setblocking(False) |
| 155 | + log.info(f"Connection from %s accepted.", peer[0]) |
| 156 | + |
| 157 | + def connect(self, host: str, port: int): |
| 158 | + """Connect to the given host and port.""" |
| 159 | + self._sock = socket.create_connection((host, port)) |
| 160 | + self._sock.setblocking(False) |
| 161 | + log.info(f"Connected to %s:%d.", host, port) |
| 162 | + |
| 163 | + def start(self): |
| 164 | + """Start the message exchange loop.""" |
| 165 | + self._running = True |
| 166 | + self._job = self._pool.spawn(self._exchange_messages) |
| 167 | + log.debug("Message exchange job started.") |
| 168 | + |
| 169 | + def stop(self, exception: Exception | None = None): |
| 170 | + """Stop the message exchange loop.""" |
| 171 | + if self._loop_running(): |
| 172 | + self._stop_loop() |
| 173 | + log.debug("Message exchange loop stopped.") |
| 174 | + |
| 175 | + if exception is not None: |
| 176 | + self._last_exc = exception |
| 177 | + |
| 178 | + def close(self, raise_exc: bool = True): |
| 179 | + """Wait for everything to be closed, raise an exception if there was an error by default.""" |
| 180 | + if self._loop_running(): |
| 181 | + self.stop() |
| 182 | + |
| 183 | + self._kill_job() |
| 184 | + self._pool.waitall() |
| 185 | + self._handle_exception(raise_exc) |
| 186 | + |
| 187 | + def receive(self, timeout: int | None = None): |
| 188 | + """ |
| 189 | + Wait for an incoming message. |
| 190 | + If `timeout` is 0, return directly with a message if available or raise `eventlet.queue.Empty`. |
| 191 | + If `timeout` is a positive integer, wait that many seconds for a message, before raising `eventlet.queue.Empty`. |
| 192 | + If `timeout` is None or not specified, block until a message is received. This method *will* return early in case of error. |
| 193 | + """ |
| 194 | + if not self._loop_running(): |
| 195 | + self.close() |
| 196 | + |
| 197 | + if timeout is None: |
| 198 | + return self._get_safe() |
| 199 | + return self._get(block=True, timeout=timeout) |
| 200 | + |
| 201 | + def send(self, msg: bytes, notify_cb: callable = None): |
| 202 | + """Put a message in the send queue.""" |
| 203 | + if not self._loop_running(): |
| 204 | + self.close() |
| 205 | + |
| 206 | + self._put(msg) |
| 207 | + |
| 208 | + def set_logging_level(self, level: int): |
| 209 | + log.setLevel(level) |
| 210 | + |
| 211 | + @classmethod |
| 212 | + def connect_to(cls, host: str = '127.0.0.1', port: int = 8765, verbose: bool = False): |
| 213 | + """Create a Duplex client connected to the given host and port.""" |
| 214 | + duplex = cls() |
| 215 | + if verbose: duplex.set_logging_level(logging.DEBUG) |
| 216 | + duplex.connect(host, port) |
| 217 | + duplex.start() |
| 218 | + return duplex |
| 219 | + |
| 220 | + @classmethod |
| 221 | + def listen_on(cls, host: str = '0.0.0.0', port: int = 8765, verbose: bool = False): |
| 222 | + """Create a Duplex server listening on the given host and port.""" |
| 223 | + duplex = cls() |
| 224 | + if verbose: duplex.set_logging_level(logging.DEBUG) |
| 225 | + duplex.listen(port, host=host) |
| 226 | + duplex.start() |
| 227 | + return duplex |
| 228 | + |
| 229 | + |
| 230 | + @classmethod |
| 231 | + @make_awaitable |
| 232 | + def listen_wait(cls, host: str = '0.0.0.0', port: int = 8765, verbose: bool = False): |
| 233 | + """Create a Duplex server and wait for a connection on given host and port.""" |
| 234 | + return cls.listen_on(host, port, verbose) |
| 235 | + |
| 236 | + @make_awaitable |
| 237 | + def wait_for_message(self, timeout: int | None = None): |
| 238 | + """ |
| 239 | + Wait for an incoming message. |
| 240 | + If `timeout` is 0, return directly with a message if available or raise `eventlet.queue.Empty`. |
| 241 | + If `timeout` is a positive integer, wait that many seconds for a message, before raising `eventlet.queue.Empty`. |
| 242 | + If `timeout` is None or not specified, block until a message is received. This method *will* still return early in case of error. |
| 243 | + """ |
| 244 | + return self.receive(timeout=timeout) |
| 245 | + |
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