Package spoon :: Package transports :: Module transports
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Source Code for Module spoon.transports.transports

  1  # 
  2  # Copyright (C) 2006, Matt Sullivan <matts@zarrf.com> 
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 23   
 24  from spoon import Serial, SpoonStream, serialprop, __SPOONLINKMSG_TAG__ 
 25  from spoon import NullLogger, LMTYPE_INIT, LMTYPE_NETWORK, LMTYPE_NETWORK_PROTO 
 26  from spoon import ber 
 27   
 28  from threading import Thread 
 29   
 30   
 31   
32 -class SpoonRPCHello(Serial):
33 """ 34 This object is sent as a very simple form of initial negotiation. 35 It contains the nodeId and the protocol version (currently always 36 1.) 37 """ 38 nodeId = serialprop() 39 version = serialprop(1)
40
41 -class LinkMessage(object):
42 """ 43 Link message is the wrapper which will contain messages sent between two directly connected nodes. 44 This message just consists of a msg type (an int) and some arbitrary attachment. The msgtype 45 determines what system will deal with the message. 46 Since this is strictly for use between directly connected nodes, there's no need for src or destination 47 fields. 48 """
49 - def __init__(self, msgtype=None, attach=None):
50 self.msgtype = msgtype 51 self.attach = attach
52 53 @ber.encoder(LinkMessage)
54 -def encode_linkmessage(fd, obj):
55 ber.Tag.from_tag(__SPOONLINKMSG_TAG__, None).write(fd) 56 b = ber.BERStream(fd) 57 b.add(obj.msgtype) 58 b.add(obj.attach) 59 b._add_eof()
60 @ber.decoder(__SPOONLINKMSG_TAG__)
61 -def decode_linkmessage(fd, tag):
62 out = LinkMessage() 63 b = ber.BERStream(fd) 64 out.msgtype = b.next() 65 out.attach = b.next() 66 # Pull the EOF off the stream 67 if b.has_next(): 68 pass 69 return out
70
71 -class TransportException(Exception):
72 pass
73
74 -class TransportHub(object):
75 """ 76 Where all of your transports connect to form your glorious new node. 77 78 79 @cvar activeTransports: A simple list of the transports that are currently active 80 @cvar links: A dict, keys are the node id of the directly connected neighbor and the values are 81 the associated transport 82 @cvar nodeId: The local node id. This must be set to the node's integer id before the spoon transport hub is started. 83 The nodeId is just a network wide, unique int. How this is determined is left as an excercise for the implementation. 84 In most cases, it should probably be something that is constant for the host/program between instances. 85 @type nodeId: int 86 """ 87 activeTransports = [] 88 links = {} 89 nodeId = None 90 _log = NullLogger() 91 92 @staticmethod
93 - def setLogger(logger):
94 """ 95 Sets a logger object for SpoonRPC to use. 96 97 This can be a python logger object, or just anything that supports that general protocol. 98 It defaults to NullLogger which does nothing with the messages. 99 """ 100 TransportHub._log = logger
101 102 @staticmethod
103 - def addTransport(t):
104 """ 105 Must be called after a transport is initialized to initiate the spoonRPC protocol. 106 107 @param t: The transport being initialized 108 @return: Nothing 109 @raise TransportException: If the protocol initialization fails for some reason. 110 """ 111 # This is our protocol initilization, just a simple exchange of nodeId 112 hello = SpoonRPCHello() 113 hello.nodeId = TransportHub.nodeId 114 lmhello = LinkMessage(LMTYPE_INIT, hello) 115 t.spoon.write(lmhello) 116 remoteLmHello = t.spoon.read() 117 remoteHello = remoteLmHello.attach 118 if (type(remoteLmHello) != LinkMessage) or (type(remoteHello) != SpoonRPCHello): 119 TransportHub._log.error("Did not get proper Hello message from neighbor across transport "+repr(t)) 120 raise TransportException("Did not get proper Hello message from neighbor across transport "+repr(t)) 121 122 # TODO Implement something to check that the transport authenticated as the proper node if it supports such a thing 123 if TransportHub.links.has_key(remoteHello.nodeId): 124 # Try to remove any transports we currently have to this nodeid 125 try: 126 TransportHub.activeTransports.remove(TransportHub.links[remoteHello.nodeId]) 127 except: 128 pass 129 del TransportHub.links[remoteHello.nodeId] 130 t.nodeId = remoteHello.nodeId 131 TransportHub.links[remoteHello.nodeId] = t 132 TransportHub.activeTransports.append(t) 133 # TODO possibly refactor this to handle other message types, but we'll figure that out later. 134 tNetwork = t.getNetwork() 135 if tNetwork: 136 tNetwork.addTransport(t, t.nodeId)
137 138 @staticmethod
139 - def removeTransport(t):
140 """ 141 Must be called after a transport has been made inactive. 142 143 """ 144 if not TransportHub.links.has_key(t.nodeId): 145 TransportHub._log.warn("Removing transport for nodeId %d and it wasn't in the links dict."%t.nodeId) 146 raise TransportException("Removing transport for nodeId %d and it wasn't in the links dict."%t.nodeId) 147 del TransportHub.links[t.nodeId] 148 TransportHub.activeTransports.remove(t) 149 # TODO possibly refactor this to handle other message types, but we'll figure that out later. 150 t.getNetwork().removeTransport(t)
151