1 ## Copyright 2002 Andrew Loewenstern, All Rights Reserved
3 from const import reactor
5 from pickle import loads, dumps
8 from ktable import KTable, K
9 from knode import KNode as Node
11 from hash import newID
13 from actions import FindNode, GetValue, KeyExpirer
14 from twisted.web import xmlrpc
15 from twisted.internet.defer import Deferred
16 from twisted.python import threadable
17 from twisted.internet.app import Application
18 from twisted.web import server
21 from bsddb3 import db ## find this at http://pybsddb.sf.net/
22 from bsddb3._db import DBNotFoundError
24 from xmlrpclib import Binary
26 # don't ping unless it's been at least this many seconds since we've heard from a peer
27 MAX_PING_INTERVAL = 60 * 15 # fifteen minutes
31 # this is the main class!
32 class Khashmir(xmlrpc.XMLRPC):
33 __slots__ = ['listener', 'node', 'table', 'store', 'itime', 'kw', 'app']
34 def __init__(self, host, port):
35 self.node = Node().init(newID(), host, port)
36 self.table = KTable(self.node)
37 self.app = Application("xmlrpc")
38 self.app.listenTCP(port, server.Site(self))
40 ## these databases may be more suited to on-disk rather than in-memory
41 # h((key, value)) -> (key, value, time) mappings
43 self.store.open(None, None, db.DB_BTREE)
45 # <insert time> -> h((key, value))
47 self.itime.set_flags(db.DB_DUP)
48 self.itime.open(None, None, db.DB_BTREE)
50 # key -> h((key, value))
52 self.kw.set_flags(db.DB_DUP)
53 self.kw.open(None, None, db.DB_BTREE)
55 KeyExpirer(store=self.store, itime=self.itime, kw=self.kw)
57 def render(self, request):
59 Override the built in render so we can have access to the request object!
60 note, crequest is probably only valid on the initial call (not after deferred!)
62 self.crequest = request
63 return xmlrpc.XMLRPC.render(self, request)
67 ####### LOCAL INTERFACE - use these methods!
68 def addContact(self, host, port):
70 ping this node and add the contact info to the table on pong!
72 n =Node().init(" "*20, host, port) # note, we
76 ## this call is async!
77 def findNode(self, id, callback, errback=None):
78 """ returns the contact info for node, or the k closest nodes, from the global table """
79 # get K nodes out of local table/cache, or the node we want
80 nodes = self.table.findNodes(id)
82 d.addCallbacks(callback, errback)
83 if len(nodes) == 1 and nodes[0].id == id :
86 # create our search state
87 state = FindNode(self, id, d.callback)
88 reactor.callFromThread(state.goWithNodes, nodes)
92 def valueForKey(self, key, callback):
93 """ returns the values found for key in global table """
94 nodes = self.table.findNodes(key)
95 # decode values, they will be base64 encoded
96 # create our search state
97 state = GetValue(self, key, callback)
98 reactor.callFromThread(state.goWithNodes, nodes)
102 ## async, but in the current implementation there is no guarantee a store does anything so there is no callback right now
103 def storeValueForKey(self, key, value, callback=None):
104 """ stores the value for key in the global table, returns immediately, no status
105 in this implementation, peers respond but don't indicate status to storing values
106 values are stored in peers on a first-come first-served basis
107 this will probably change so more than one value can be stored under a key
109 def _storeValueForKey(nodes, key=key, value=value, response=callback , default= lambda t: "didn't respond"):
111 # default callback - this will get called for each successful store value
112 def _storedValueHandler(sender):
114 response=_storedValueHandler
116 if node.id != self.node.id:
117 df = node.storeValue(key, value, self.node.senderDict())
118 df.addCallbacks(response, default)
119 # this call is asynch
120 self.findNode(key, _storeValueForKey)
123 def insertNode(self, n):
125 insert a node in our local table, pinging oldest contact in bucket, if necessary
127 If all you have is a host/port, then use addContact, which calls this method after
128 receiving the PONG from the remote node. The reason for the seperation is we can't insert
129 a node into the table without it's peer-ID. That means of course the node passed into this
130 method needs to be a properly formed Node object with a valid ID.
132 old = self.table.insertNode(n)
133 if old and (time.time() - old.lastSeen) > MAX_PING_INTERVAL and old.id != self.node.id:
134 # the bucket is full, check to see if old node is still around and if so, replace it
136 ## these are the callbacks used when we ping the oldest node in a bucket
137 def _staleNodeHandler(oldnode=old, newnode = n):
138 """ called if the pinged node never responds """
139 self.table.replaceStaleNode(old, newnode)
141 def _notStaleNodeHandler(sender, old=old):
142 """ called when we get a ping from the remote node """
143 sender = Node().initWithSenderDict(sender)
144 if sender.id == old.id:
145 self.table.insertNode(old)
147 df = old.ping(self.node.senderDict())
148 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
151 def sendPing(self, node):
155 df = node.ping(self.node.senderDict())
156 ## these are the callbacks we use when we issue a PING
157 def _pongHandler(sender, id=node.id, host=node.host, port=node.port, table=self.table):
158 sender = Node().initWithSenderDict(sender)
159 if id != 20 * ' ' and id != sender.id:
160 # whoah, got response from different peer than we were expecting
163 #print "Got PONG from %s at %s:%s" % (`msg['id']`, t.target.host, t.target.port)
164 sender['host'] = host
165 sender['port'] = port
166 n = Node().initWithDict(sender)
169 def _defaultPong(err):
170 # this should probably increment a failed message counter and dump the node if it gets over a threshold
173 df.addCallbacks(_pongHandler,_defaultPong)
176 def findCloseNodes(self):
178 This does a findNode on the ID one away from our own.
179 This will allow us to populate our table with nodes on our network closest to our own.
180 This is called as soon as we start up with an empty table
182 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
185 self.findNode(id, callback)
187 def refreshTable(self):
194 for bucket in self.table.buckets:
195 if time.time() - bucket.lastAccessed >= 60 * 60:
196 id = randRange(bucket.min, bucket.max)
197 self.findNode(id, callback)
201 ##### INCOMING MESSAGE HANDLERS
203 def xmlrpc_ping(self, sender):
205 takes sender dict = {'id', <id>, 'port', port} optional keys = 'ip'
208 ip = self.crequest.getClientIP()
210 n = Node().initWithDict(sender)
212 return self.node.senderDict()
214 def xmlrpc_find_node(self, target, sender):
215 nodes = self.table.findNodes(target)
216 nodes = map(lambda node: node.senderDict(), nodes)
217 ip = self.crequest.getClientIP()
219 n = Node().initWithDict(sender)
221 return nodes, self.node.senderDict()
223 def xmlrpc_store_value(self, key, value, sender):
225 h1 = sha(key+value.data).digest()
227 if not self.store.has_key(h1):
228 v = dumps((key, value.data, t))
229 self.store.put(h1, v)
230 self.itime.put(t, h1)
233 # update last insert time
234 tup = loads(self.store[h1])
235 self.store[h1] = dumps((tup[0], tup[1], t))
236 self.itime.put(t, h1)
238 ip = self.crequest.getClientIP()
240 n = Node().initWithDict(sender)
242 return self.node.senderDict()
244 def xmlrpc_find_value(self, key, sender):
245 ip = self.crequest.getClientIP()
248 n = Node().initWithDict(sender)
251 if self.kw.has_key(key):
257 v = loads(self.store[h1])[1]
260 l = map(lambda v: Binary(v), l)
261 return {'values' : l}, self.node.senderDict()
263 nodes = self.table.findNodes(key)
264 nodes = map(lambda node: node.senderDict(), nodes)
265 return {'nodes' : nodes}, self.node.senderDict()
273 def test_build_net(quiet=0, peers=24, host='localhost', pause=1):
274 from whrandom import randrange
280 print "Building %s peer table." % peers
282 for i in xrange(peers):
283 a = Khashmir(host, port + i)
287 thread.start_new_thread(l[0].app.run, ())
293 print "adding contacts...."
296 n = l[randrange(0, len(l))].node
297 peer.addContact(host, n.port)
298 n = l[randrange(0, len(l))].node
299 peer.addContact(host, n.port)
300 n = l[randrange(0, len(l))].node
301 peer.addContact(host, n.port)
306 print "finding close nodes...."
309 peer.findCloseNodes()
315 # peer.refreshTable()
318 def test_find_nodes(l, quiet=0):
319 import threading, sys
320 from whrandom import randrange
321 flag = threading.Event()
325 a = l[randrange(0,n)]
326 b = l[randrange(0,n)]
328 def callback(nodes, flag=flag, id = b.node.id):
329 if (len(nodes) >0) and (nodes[0].id == id):
330 print "test_find_nodes PASSED"
332 print "test_find_nodes FAILED"
334 a.findNode(b.node.id, callback)
337 def test_find_value(l, quiet=0):
338 from whrandom import randrange
340 from hash import newID
341 import time, threading, sys
343 fa = threading.Event()
344 fb = threading.Event()
345 fc = threading.Event()
348 a = l[randrange(0,n)]
349 b = l[randrange(0,n)]
350 c = l[randrange(0,n)]
351 d = l[randrange(0,n)]
356 print "inserting value..."
358 a.storeValueForKey(key, value)
364 def __init__(self, flag, value=value):
368 def callback(self, values):
370 if(len(values) == 0):
378 if self.val in values:
383 b.valueForKey(key, cb(fa).callback)
385 c.valueForKey(key, cb(fb).callback)
387 d.valueForKey(key, cb(fc).callback)
392 k = Khashmir('localhost', port)
393 thread.start_new_thread(k.app.run, ())
396 if __name__ == "__main__":
399 print "finding nodes..."
402 print "inserting and fetching values..."