gps303/collector.py

   1 """ TCP server that communicates with terminals """
   2
   3 from configparser import ConfigParser
   4 from logging import getLogger
   5 from os import umask
   6 from socket import (
   7     socket,
   8     AF_INET6,
   9     SOCK_STREAM,
  10     SOL_SOCKET,
  11     SO_KEEPALIVE,
  12     SO_REUSEADDR,
  13 )
  14 from struct import pack
  15 from time import time
  16 from typing import Dict, List, Optional, Tuple
  17 import zmq
  18
  19 from . import common
  20 from .gps303proto import (
  21     GPS303Conn,
  22     HIBERNATION,
  23     LOGIN,
  24     inline_response,
  25     parse_message,
  26     proto_of_message,
  27 )
  28 from .zmsg import Bcast, Resp
  29
  30 log = getLogger("gps303/collector")
  31
  32 MAXBUFFER: int = 4096
  33
  34
  35 class Client:
  36     """Connected socket to the terminal plus buffer and metadata"""
  37
  38     def __init__(self, sock: socket, addr: Tuple[str, int]) -> None:
  39         self.sock = sock
  40         self.addr = addr
  41         self.stream = GPS303Conn()
  42         self.imei: Optional[str] = None
  43
  44     def close(self) -> None:
  45         log.debug("Closing fd %d (IMEI %s)", self.sock.fileno(), self.imei)
  46         self.sock.close()
  47         rest = self.stream.close()
  48         if rest:
  49             log.warning("%d bytes in buffer on close: %s", len(rest), rest)
  50
  51     def recv(self) -> Optional[List[Tuple[float, Tuple[str, int], bytes]]]:
  52         """Read from the socket and parse complete messages"""
  53         try:
  54             segment = self.sock.recv(MAXBUFFER)
  55         except OSError as e:
  56             log.warning(
  57                 "Reading from fd %d (IMEI %s): %s",
  58                 self.sock.fileno(),
  59                 self.imei,
  60                 e,
  61             )
  62             return None
  63         if not segment:  # Terminal has closed connection
  64             log.info(
  65                 "EOF reading from fd %d (IMEI %s)",
  66                 self.sock.fileno(),
  67                 self.imei,
  68             )
  69             return None
  70         when = time()
  71         msgs = []
  72         for elem in self.stream.recv(segment):
  73             if isinstance(elem, bytes):
  74                 msgs.append((when, self.addr, elem))
  75             else:
  76                 log.warning(
  77                     "%s from fd %d (IMEI %s)",
  78                     elem,
  79                     self.sock.fileno(),
  80                     self.imei,
  81                 )
  82         return msgs
  83
  84     def send(self, buffer: bytes) -> None:
  85         try:
  86             self.sock.send(self.stream.enframe(buffer))
  87         except OSError as e:
  88             log.error(
  89                 "Sending to fd %d (IMEI %s): %s",
  90                 self.sock.fileno(),
  91                 self.imei,
  92                 e,
  93             )
  94
  95     def set_imei(self, imei: str) -> None:
  96         self.imei = imei
  97
  98
  99 class Clients:
 100     def __init__(self) -> None:
 101         self.by_fd: Dict[int, Client] = {}
 102         self.by_imei: Dict[str, Client] = {}
 103
 104     def add(self, clntsock: socket, clntaddr: Tuple[str, int]) -> int:
 105         fd = clntsock.fileno()
 106         log.info("Start serving fd %d from %s", fd, clntaddr)
 107         self.by_fd[fd] = Client(clntsock, clntaddr)
 108         return fd
 109
 110     def stop(self, fd: int) -> None:
 111         clnt = self.by_fd[fd]
 112         log.info("Stop serving fd %d (IMEI %s)", clnt.sock.fileno(), clnt.imei)
 113         clnt.close()
 114         if clnt.imei:
 115             del self.by_imei[clnt.imei]
 116         del self.by_fd[fd]
 117
 118     def recv(
 119         self, fd: int
 120     ) -> Optional[List[Tuple[Optional[str], float, Tuple[str, int], bytes]]]:
 121         clnt = self.by_fd[fd]
 122         msgs = clnt.recv()
 123         if msgs is None:
 124             return None
 125         result = []
 126         for when, peeraddr, packet in msgs:
 127             if proto_of_message(packet) == LOGIN.PROTO:
 128                 msg = parse_message(packet)
 129                 if isinstance(msg, LOGIN):  # Can be unparseable
 130                     if clnt.imei is None:
 131                         clnt.imei = msg.imei
 132                         log.info(
 133                             "LOGIN from fd %d (IMEI %s)",
 134                             clnt.sock.fileno(),
 135                             clnt.imei,
 136                         )
 137                         oldclnt = self.by_imei.get(clnt.imei)
 138                         if oldclnt is not None:
 139                             log.info(
 140                                 "Orphaning fd %d with the same IMEI",
 141                                 oldclnt.sock.fileno(),
 142                             )
 143                             oldclnt.imei = None
 144                     self.by_imei[clnt.imei] = clnt
 145                 else:
 146                     log.warning(
 147                         "Login message from %s: %s, but client imei unfilled",
 148                         peeraddr,
 149                         packet,
 150                     )
 151             result.append((clnt.imei, when, peeraddr, packet))
 152             log.debug(
 153                 "Received from %s (IMEI %s): %s",
 154                 peeraddr,
 155                 clnt.imei,
 156                 packet.hex(),
 157             )
 158         return result
 159
 160     def response(self, resp: Resp) -> None:
 161         if resp.imei in self.by_imei:
 162             self.by_imei[resp.imei].send(resp.packet)
 163         else:
 164             log.info("Not connected (IMEI %s)", resp.imei)
 165
 166
 167 def runserver(conf: ConfigParser, handle_hibernate: bool = True) -> None:
 168     # Is this https://github.com/zeromq/pyzmq/issues/1627 still not fixed?!
 169     zctx = zmq.Context()  # type: ignore
 170     zpub = zctx.socket(zmq.PUB)  # type: ignore
 171     zpull = zctx.socket(zmq.PULL)  # type: ignore
 172     oldmask = umask(0o117)
 173     zpub.bind(conf.get("collector", "publishurl"))
 174     zpull.bind(conf.get("collector", "listenurl"))
 175     umask(oldmask)
 176     tcpl = socket(AF_INET6, SOCK_STREAM)
 177     tcpl.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
 178     tcpl.bind(("", conf.getint("collector", "port")))
 179     tcpl.listen(5)
 180     tcpfd = tcpl.fileno()
 181     poller = zmq.Poller()  # type: ignore
 182     poller.register(zpull, flags=zmq.POLLIN)
 183     poller.register(tcpfd, flags=zmq.POLLIN)
 184     clients = Clients()
 185     try:
 186         while True:
 187             tosend = []
 188             topoll = []
 189             tostop = []
 190             events = poller.poll(1000)
 191             for sk, fl in events:
 192                 if sk is zpull:
 193                     while True:
 194                         try:
 195                             msg = zpull.recv(zmq.NOBLOCK)
 196                             zmsg = Resp(msg)
 197                             tosend.append(zmsg)
 198                         except zmq.Again:
 199                             break
 200                 elif sk == tcpfd:
 201                     clntsock, clntaddr = tcpl.accept()
 202                     clntsock.setsockopt(SOL_SOCKET, SO_KEEPALIVE, 1)
 203                     topoll.append((clntsock, clntaddr))
 204                 elif fl & zmq.POLLIN:
 205                     received = clients.recv(sk)
 206                     if received is None:
 207                         log.debug("Terminal gone from fd %d", sk)
 208                         tostop.append(sk)
 209                     else:
 210                         for imei, when, peeraddr, packet in received:
 211                             proto = proto_of_message(packet)
 212                             zpub.send(
 213                                 Bcast(
 214                                     proto=proto,
 215                                     imei=imei,
 216                                     when=when,
 217                                     peeraddr=peeraddr,
 218                                     packet=packet,
 219                                 ).packed
 220                             )
 221                             if proto == HIBERNATION.PROTO and handle_hibernate:
 222                                 log.debug(
 223                                     "HIBERNATION from fd %d (IMEI %s)",
 224                                     sk,
 225                                     imei,
 226                                 )
 227                                 tostop.append(sk)
 228                             respmsg = inline_response(packet)
 229                             if respmsg is not None:
 230                                 tosend.append(
 231                                     Resp(imei=imei, when=when, packet=respmsg)
 232                                 )
 233                 else:
 234                     log.debug("Stray event: %s on socket %s", fl, sk)
 235             # poll queue consumed, make changes now
 236             for zmsg in tosend:
 237                 zpub.send(
 238                     Bcast(
 239                         is_incoming=False,
 240                         proto=proto_of_message(zmsg.packet),
 241                         when=zmsg.when,
 242                         imei=zmsg.imei,
 243                         packet=zmsg.packet,
 244                     ).packed
 245                 )
 246                 log.debug("Sending to the client: %s", zmsg)
 247                 clients.response(zmsg)
 248             for fd in tostop:
 249                 poller.unregister(fd)  # type: ignore
 250                 clients.stop(fd)
 251             for clntsock, clntaddr in topoll:
 252                 fd = clients.add(clntsock, clntaddr)
 253                 poller.register(fd, flags=zmq.POLLIN)
 254     except KeyboardInterrupt:
 255         zpub.close()
 256         zpull.close()
 257         zctx.destroy()  # type: ignore
 258         tcpl.close()
 259
 260
 261 if __name__.endswith("__main__"):
 262     runserver(common.init(log))