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 base64 import decodestring as decode
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 def cbwrap(values, cb=callback):
97 values = map(lambda x: decode(x), values)
99 # create our search state
100 state = GetValue(self, key, cbwrap)
101 reactor.callFromThread(state.goWithNodes, nodes)
105 ## async, but in the current implementation there is no guarantee a store does anything so there is no callback right now
106 def storeValueForKey(self, key, value, callback=None):
107 """ stores the value for key in the global table, returns immediately, no status
108 in this implementation, peers respond but don't indicate status to storing values
109 values are stored in peers on a first-come first-served basis
110 this will probably change so more than one value can be stored under a key
112 def _storeValueForKey(nodes, key=key, value=value, response=callback , default= lambda t: "didn't respond"):
114 # default callback - this will get called for each successful store value
115 def _storedValueHandler(sender):
117 response=_storedValueHandler
119 if node.id != self.node.id:
120 df = node.storeValue(key, value, self.node.senderDict())
121 df.addCallbacks(response, default)
122 # this call is asynch
123 self.findNode(key, _storeValueForKey)
126 def insertNode(self, n):
128 insert a node in our local table, pinging oldest contact in bucket, if necessary
130 If all you have is a host/port, then use addContact, which calls this method after
131 receiving the PONG from the remote node. The reason for the seperation is we can't insert
132 a node into the table without it's peer-ID. That means of course the node passed into this
133 method needs to be a properly formed Node object with a valid ID.
135 old = self.table.insertNode(n)
136 if old and (time.time() - old.lastSeen) > MAX_PING_INTERVAL and old.id != self.node.id:
137 # the bucket is full, check to see if old node is still around and if so, replace it
139 ## these are the callbacks used when we ping the oldest node in a bucket
140 def _staleNodeHandler(oldnode=old, newnode = n):
141 """ called if the pinged node never responds """
142 self.table.replaceStaleNode(old, newnode)
144 def _notStaleNodeHandler(sender, old=old):
145 """ called when we get a ping from the remote node """
146 if sender['id'] == old.id:
147 self.table.insertNode(old)
149 df = old.ping(self.node.senderDict())
150 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
153 def sendPing(self, node):
157 df = node.ping(self.node.senderDict())
158 ## these are the callbacks we use when we issue a PING
159 def _pongHandler(sender, id=node.id, host=node.host, port=node.port, table=self.table):
160 if id != 20 * ' ' and id != sender['id']:
161 # whoah, got response from different peer than we were expecting
164 #print "Got PONG from %s at %s:%s" % (`msg['id']`, t.target.host, t.target.port)
165 sender['host'] = host
166 sender['port'] = port
167 n = Node().initWithDict(sender)
170 def _defaultPong(err):
171 # this should probably increment a failed message counter and dump the node if it gets over a threshold
174 df.addCallbacks(_pongHandler,_defaultPong)
177 def findCloseNodes(self):
179 This does a findNode on the ID one away from our own.
180 This will allow us to populate our table with nodes on our network closest to our own.
181 This is called as soon as we start up with an empty table
183 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
186 self.findNode(id, callback)
188 def refreshTable(self):
195 for bucket in self.table.buckets:
196 if time.time() - bucket.lastAccessed >= 60 * 60:
197 id = randRange(bucket.min, bucket.max)
198 self.findNode(id, callback)
202 ##### INCOMING MESSAGE HANDLERS
204 def xmlrpc_ping(self, sender):
206 takes sender dict = {'id', <id>, 'port', port} optional keys = 'ip'
209 ip = self.crequest.getClientIP()
211 n = Node().initWithDict(sender)
213 return self.node.senderDict()
215 def xmlrpc_find_node(self, target, sender):
216 nodes = self.table.findNodes(target)
217 nodes = map(lambda node: node.senderDict(), nodes)
218 ip = self.crequest.getClientIP()
220 n = Node().initWithDict(sender)
222 return nodes, self.node.senderDict()
224 def xmlrpc_store_value(self, key, value, sender):
226 h1 = sha(key+value).digest()
228 if not self.store.has_key(h1):
229 v = dumps((key, value, t))
230 self.store.put(h1, v)
231 self.itime.put(t, h1)
234 # update last insert time
235 tup = loads(self.store[h1])
236 self.store[h1] = dumps((tup[0], tup[1], t))
237 self.itime.put(t, h1)
239 ip = self.crequest.getClientIP()
241 n = Node().initWithDict(sender)
243 return self.node.senderDict()
245 def xmlrpc_find_value(self, key, sender):
246 ip = self.crequest.getClientIP()
249 n = Node().initWithDict(sender)
252 if self.kw.has_key(key):
258 v = loads(self.store[h1])[1]
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..."