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 if sender['id'] == old.id:
144 self.table.insertNode(old)
146 df = old.ping(self.node.senderDict())
147 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
150 def sendPing(self, node):
154 df = node.ping(self.node.senderDict())
155 ## these are the callbacks we use when we issue a PING
156 def _pongHandler(sender, id=node.id, host=node.host, port=node.port, table=self.table):
157 if id != 20 * ' ' and id != sender['id']:
158 # whoah, got response from different peer than we were expecting
161 #print "Got PONG from %s at %s:%s" % (`msg['id']`, t.target.host, t.target.port)
162 sender['host'] = host
163 sender['port'] = port
164 n = Node().initWithDict(sender)
167 def _defaultPong(err):
168 # this should probably increment a failed message counter and dump the node if it gets over a threshold
171 df.addCallbacks(_pongHandler,_defaultPong)
174 def findCloseNodes(self):
176 This does a findNode on the ID one away from our own.
177 This will allow us to populate our table with nodes on our network closest to our own.
178 This is called as soon as we start up with an empty table
180 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
183 self.findNode(id, callback)
185 def refreshTable(self):
192 for bucket in self.table.buckets:
193 if time.time() - bucket.lastAccessed >= 60 * 60:
194 id = randRange(bucket.min, bucket.max)
195 self.findNode(id, callback)
199 ##### INCOMING MESSAGE HANDLERS
201 def xmlrpc_ping(self, sender):
203 takes sender dict = {'id', <id>, 'port', port} optional keys = 'ip'
206 ip = self.crequest.getClientIP()
208 n = Node().initWithDict(sender)
210 return self.node.senderDict()
212 def xmlrpc_find_node(self, target, sender):
213 nodes = self.table.findNodes(target)
214 nodes = map(lambda node: node.senderDict(), nodes)
215 ip = self.crequest.getClientIP()
217 n = Node().initWithDict(sender)
219 return nodes, self.node.senderDict()
221 def xmlrpc_store_value(self, key, value, sender):
223 h1 = sha(key+value.data).digest()
225 if not self.store.has_key(h1):
226 v = dumps((key, value.data, t))
227 self.store.put(h1, v)
228 self.itime.put(t, h1)
231 # update last insert time
232 tup = loads(self.store[h1])
233 self.store[h1] = dumps((tup[0], tup[1], t))
234 self.itime.put(t, h1)
236 ip = self.crequest.getClientIP()
238 n = Node().initWithDict(sender)
240 return self.node.senderDict()
242 def xmlrpc_find_value(self, key, sender):
243 ip = self.crequest.getClientIP()
246 n = Node().initWithDict(sender)
249 if self.kw.has_key(key):
255 v = loads(self.store[h1])[1]
258 l = map(lambda v: Binary(v), l)
259 return {'values' : l}, self.node.senderDict()
261 nodes = self.table.findNodes(key)
262 nodes = map(lambda node: node.senderDict(), nodes)
263 return {'nodes' : nodes}, self.node.senderDict()
271 def test_build_net(quiet=0, peers=24, host='localhost', pause=1):
272 from whrandom import randrange
278 print "Building %s peer table." % peers
280 for i in xrange(peers):
281 a = Khashmir(host, port + i)
285 thread.start_new_thread(l[0].app.run, ())
291 print "adding contacts...."
294 n = l[randrange(0, len(l))].node
295 peer.addContact(host, n.port)
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)
304 print "finding close nodes...."
307 peer.findCloseNodes()
313 # peer.refreshTable()
316 def test_find_nodes(l, quiet=0):
317 import threading, sys
318 from whrandom import randrange
319 flag = threading.Event()
323 a = l[randrange(0,n)]
324 b = l[randrange(0,n)]
326 def callback(nodes, flag=flag, id = b.node.id):
327 if (len(nodes) >0) and (nodes[0].id == id):
328 print "test_find_nodes PASSED"
330 print "test_find_nodes FAILED"
332 a.findNode(b.node.id, callback)
335 def test_find_value(l, quiet=0):
336 from whrandom import randrange
338 from hash import newID
339 import time, threading, sys
341 fa = threading.Event()
342 fb = threading.Event()
343 fc = threading.Event()
346 a = l[randrange(0,n)]
347 b = l[randrange(0,n)]
348 c = l[randrange(0,n)]
349 d = l[randrange(0,n)]
354 print "inserting value..."
356 a.storeValueForKey(key, value)
362 def __init__(self, flag, value=value):
366 def callback(self, values):
368 if(len(values) == 0):
376 if self.val in values:
381 b.valueForKey(key, cb(fa).callback)
383 c.valueForKey(key, cb(fb).callback)
385 d.valueForKey(key, cb(fc).callback)
390 k = Khashmir('localhost', port)
391 thread.start_new_thread(k.app.run, ())
394 if __name__ == "__main__":
397 print "finding nodes..."
400 print "inserting and fetching values..."