gps303/collector.py

   1 """ TCP server that communicates with terminals """
   2
   3 from getopt import getopt
   4 from logging import getLogger, StreamHandler, DEBUG, INFO
   5 from logging.handlers import SysLogHandler
   6 from socket import socket, AF_INET, SOCK_STREAM, SOL_SOCKET, SO_REUSEADDR
   7 from time import time
   8 import sys
   9 import zmq
  10
  11 from .config import readconfig
  12 from .gps303proto import handle_packet, make_response, LOGIN, set_config
  13
  14 CONF = "/etc/gps303.conf"
  15
  16 log = getLogger("gps303/collector")
  17
  18
  19 class Bcast:
  20     """Zmq message to broadcast what was received from the terminal"""
  21     def __init__(self, imei, msg):
  22         self.as_bytes = imei.encode() + msg.encode()
  23
  24
  25 class Resp:
  26     """Zmq message received from a third party to send to the terminal"""
  27     def __init__(self, msg):
  28         self.imei = msg[:16].decode()
  29         self.payload = msg[16:]
  30
  31
  32 class Client:
  33     """Connected socket to the terminal plus buffer and metadata"""
  34     def __init__(self, sock, addr):
  35         self.sock = sock
  36         self.addr = addr
  37         self.buffer = b""
  38         self.imei = None
  39
  40     def close(self):
  41         self.sock.close()
  42         self.buffer = b""
  43         self.imei = None
  44
  45     def recv(self):
  46         segment = self.sock.recv(4096)
  47         if not segment:
  48             return None
  49         when = time()
  50         self.buffer += segment
  51         # implement framing properly
  52         msg = handle_packet(packet, self.addr, when)
  53         self.buffer = self.buffer[len(packet):]
  54         if isinstance(msg, LOGIN):
  55             self.imei = msg.imei
  56         return msg
  57
  58     def send(self, buffer):
  59         self.sock.send(buffer)
  60
  61
  62 class Clients:
  63     def __init__(self):
  64         self.by_fd = {}
  65         self.by_imei = {}
  66
  67     def add(self, clntsock, clntaddr):
  68         fd = clntsock.fileno()
  69         self.by_fd[fd] = Client(clntsock, clntaddr)
  70         return fd
  71
  72     def stop(self, fd):
  73         clnt = by_fd[fd]
  74         clnt.close()
  75         if clnt.imei:
  76             del self.by_imei[clnt.imei]
  77         del self.by_fd[fd]
  78
  79     def recv(self, fd):
  80         clnt = by_fd[fd]
  81         msg = clnt.recv()
  82         if isinstance(msg, LOGIN):
  83             self.by_imei[clnt.imei] = clnt
  84         return clnt.imei, msg
  85
  86     def response(self, zmsg):
  87         if zmsg.imei in self.by_imei:
  88             clnt = self.by_imei[zmsg.imei].send(zmsg.payload)
  89
  90
  91 def runserver(opts, conf):
  92     zctx = zmq.Context()
  93     zpub = zctx.socket(zmq.PUB)
  94     zpub.bind(conf.get("collector", "publishurl"))
  95     zsub = zctx.socket(zmq.SUB)
  96     zsub.connect(conf.get("collector", "listenurl"))
  97     tcpl = socket(AF_INET, SOCK_STREAM)
  98     tcpl.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
  99     tcpl.bind(("", conf.getint("collector", "port")))
 100     tcpl.listen(5)
 101     tcpfd = tcpl.fileno()
 102     poller = zmq.Poller()
 103     poller.register(zsub, flags=zmq.POLLIN)
 104     poller.register(tcpfd, flags=zmq.POLLIN)
 105     clients = Clients()
 106     try:
 107         while True:
 108             tosend = []
 109             topoll = []
 110             tostop = []
 111             events = poller.poll(10)
 112             for sk, fl in events:
 113                 if sk is zsub:
 114                     while True:
 115                         try:
 116                             msg = zsub.recv(zmq.NOBLOCK)
 117                             tosend.append(Resp(msg))
 118                         except zmq.Again:
 119                             break
 120                 elif sk == tcpfd:
 121                     clntsock, clntaddr = ctlsock.accept()
 122                     topoll.append((clntsock, clntaddr))
 123                 else:
 124                     imei, msg = clients.recv(sk)
 125                     zpub.send(Bcast(imei, msg).as_bytes)
 126                     if msg is None or isinstance(msg, HIBERNATION):
 127                         tostop.append(sk)
 128             # poll queue consumed, make changes now
 129             for fd in tostop:
 130                 clients.stop(fd)
 131                 pollset.unregister(fd)
 132             for zmsg in tosend:
 133                 clients.response(zmsg)
 134             for clntsock, clntaddr in topoll:
 135                 fd = clients.add(clntsock, clntaddr)
 136                 pollset.register(fd)
 137     except KeyboardInterrupt:
 138         pass
 139
 140
 141 if __name__.endswith("__main__"):
 142     opts, _ = getopt(sys.argv[1:], "c:d")
 143     opts = dict(opts)
 144     conf = readconfig(opts["-c"] if "-c" in opts else CONF)
 145     if sys.stdout.isatty():
 146         log.addHandler(StreamHandler(sys.stderr))
 147     else:
 148         log.addHandler(SysLogHandler(address="/dev/log"))
 149     log.setLevel(DEBUG if "-d" in opts else INFO)
 150     log.info("starting with options: %s", opts)
 151     runserver(opts, conf)