code/breadcrumb/server/net.py

   1 #-*- coding: utf8 -*-
   2 """Network code for the Breadcrumb server."""
   3
   4 # Copyright (C) 2008 Laurens Van Houtven <lvh at laurensvh.be>
   5 # This program is free software: you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation, either version 3 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 from twisted.internet import reactor
  19 from twisted.internet.protocol import DatagramProtocol  # UDP
  20 from twisted.internet.protocol import Protocol, Factory # TCP
  21
  22 import os
  23 import sys
  24 import time
  25 import atexit
  26 import logging
  27 import decoding
  28
  29 sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
  30 import common.consts as consts
  31
  32 class BreadcrumbServer:
  33     """A superclass for Breadcrumb servers."""
  34     def __init__(self, handler = None):
  35         self.handler = handler
  36         atexit.register(self.clean_up)
  37
  38         self.keepdatapoints = False
  39         self.datapoints = []
  40
  41     def new_crumb(self, packed):
  42         """Unpacks a new crumb, checks it, and passes it to the handler."""
  43
  44         logging.debug('Got a new crumb, sending to decoder...')
  45         point = decoding.decodecrumb(packed)
  46
  47         if self.keepdatapoints:
  48             self.datapoints.append(point)
  49
  50         if 'handlerid' in point and 'handlermsg' in point:
  51             id, msg = point['handlerid'], point['handlermsg']
  52             self.handler.newmessage(id, msg)
  53
  54         self.handler.newpoint(point)
  55
  56     def clean_up(self):
  57         """Cleans up before closing.
  58
  59         This tells the handler that we're about to shut down, so it has a
  60         chance to close connections, finalize files...
  61         """
  62         try:
  63             logging.info('Cleaning up...')
  64             self.handler.cleanup()
  65         except NameError:
  66             logging.info('... but the handler has no cleanup method.')
  67
  68 class BreadcrumbTCPServer(BreadcrumbServer, Protocol):
  69     """A TCP server for the breadcrumb protocol."""
  70     def __init__(self, handler = None):
  71         BreadcrumbServer.__init__(self, handler)
  72
  73     def dataReceived(self, crumb):
  74         """Handles a new crumb, received over TCP."""
  75         self.new_crumb(crumb)
  76
  77 class BreadcrumbUDPServer(BreadcrumbServer, DatagramProtocol):
  78     """A UDP server for the breadcrumb protocol."""
  79     def __init__(self, handler = None):
  80         BreadcrumbServer.__init__(self, handler)
  81         logging.debug("New BreadcrumbUDPServer instance created.")
  82
  83     def datagramReceived(self, crumb, (host, port)):
  84         """Handles a new crumb, received over UDP."""
  85         logging.debug("received something from %s:%d" % (host, port))
  86         self.new_crumb(crumb)
  87
  88 def start_server(port = None, handler = None, encap = 'UDP'):
  89     """Runs the Breadcrumb server.
  90
  91     The server argument is either the server proper (for UDP servers) or the
  92     relevant factory (for TCP and derived protocols).
  93     """
  94     logging.info("Booting the Breadcrumb server (version %s)" % consts.VERSION)
  95     logging.debug("Server started at %s." % time.ctime())
  96
  97     try:
  98         port = int(port)
  99     except ValueError:
 100         logging.error("Got noninteger port %s, can't start server..." % port)
 101         raise RuntimeError, 'Bad port: %s' % port
 102
 103     encap = encap.upper()
 104     if encap == 'TCP':
 105         server = BreadcrumbTCPServer(handler = handler)
 106
 107         factory = Factory()
 108         factory.protocol = server
 109
 110         if port is None:
 111             port = consts.DEFAULT_TCP_PORT
 112
 113         logging.debug("Prepared TCP reactor on port %d" % port)
 114         reactor.listenTCP(port, factory)
 115
 116     elif encap == 'UDP':
 117         server = BreadcrumbUDPServer(handler = handler)
 118
 119         if port is None:
 120             port = consts.DEFAULT_UDP_PORT
 121
 122         logging.debug("Prepared UDP reactor on port %d" % port)
 123         reactor.listenUDP(port, server)
 124
 125     elif encap == 'SSH':
 126         # TODO: Implement
 127         raise NotImplementedError, 'SSH protocol server not implemented.'
 128     else:
 129         raise RuntimeError, 'Unknown encapsulation %s' % encap
 130
 131     reactor.run()