1 ## Copyright 2002-2004 Andrew Loewenstern, All Rights Reserved
2 # see LICENSE.txt for license information
5 warnings.simplefilter("ignore", DeprecationWarning)
7 from datetime import datetime, timedelta
8 from random import randrange
12 from twisted.internet.defer import Deferred
13 from twisted.internet import protocol, reactor
14 from twisted.trial import unittest
17 from ktable import KTable
18 from knode import KNodeBase, KNodeRead, KNodeWrite, NULL_ID
19 from khash import newID, newIDInRange
20 from actions import FindNode, GetValue, KeyExpirer, StoreValue
23 # this is the base class, has base functionality and find node, no key-value mappings
24 class KhashmirBase(protocol.Factory):
26 def __init__(self, config, cache_dir='/tmp'):
28 self.setup(config, cache_dir)
30 def setup(self, config, cache_dir):
32 self.port = config['PORT']
33 self.store = DB(os.path.join(cache_dir, 'khashmir.' + str(self.port) + '.db'))
34 self.node = self._loadSelfNode('', self.port)
35 self.table = KTable(self.node, config)
36 self.token_secrets = [newID()]
37 #self.app = service.Application("krpc")
38 self.udp = krpc.hostbroker(self, config)
39 self.udp.protocol = krpc.KRPC
40 self.listenport = reactor.listenUDP(self.port, self.udp)
41 self._loadRoutingTable()
42 self.expirer = KeyExpirer(self.store, config)
43 self.refreshTable(force=1)
44 self.next_checkpoint = reactor.callLater(60, self.checkpoint, (1,))
46 def Node(self, id, host = None, port = None):
47 """Create a new node."""
48 n = self._Node(id, host, port)
50 n.conn = self.udp.connectionForAddr((n.host, n.port))
54 self.listenport.stopListening()
56 def _loadSelfNode(self, host, port):
57 id = self.store.getSelfNode()
60 return self._Node(id, host, port)
62 def checkpoint(self, auto=0):
63 self.token_secrets.insert(0, newID())
64 if len(self.token_secrets) > 3:
65 self.token_secrets.pop()
66 self.store.saveSelfNode(self.node.id)
67 self.store.dumpRoutingTable(self.table.buckets)
70 self.next_checkpoint = reactor.callLater(randrange(int(self.config['CHECKPOINT_INTERVAL'] * .9),
71 int(self.config['CHECKPOINT_INTERVAL'] * 1.1)),
72 self.checkpoint, (1,))
74 def _loadRoutingTable(self):
76 load routing table nodes from database
77 it's usually a good idea to call refreshTable(force=1) after loading the table
79 nodes = self.store.getRoutingTable()
81 n = self.Node(rec[0], rec[1], int(rec[2]))
82 self.table.insertNode(n, contacted=0)
86 ####### LOCAL INTERFACE - use these methods!
87 def addContact(self, host, port, callback=None, errback=None):
89 ping this node and add the contact info to the table on pong!
91 n = self.Node(NULL_ID, host, port)
92 self.sendJoin(n, callback=callback, errback=errback)
94 ## this call is async!
95 def findNode(self, id, callback, errback=None):
96 """ returns the contact info for node, or the k closest nodes, from the global table """
97 # get K nodes out of local table/cache, or the node we want
98 nodes = self.table.findNodes(id)
101 d.addCallbacks(callback, errback)
103 d.addCallback(callback)
104 if len(nodes) == 1 and nodes[0].id == id :
107 # create our search state
108 state = FindNode(self, id, d.callback, self.config)
109 reactor.callLater(0, state.goWithNodes, nodes)
111 def insertNode(self, n, contacted=1):
113 insert a node in our local table, pinging oldest contact in bucket, if necessary
115 If all you have is a host/port, then use addContact, which calls this method after
116 receiving the PONG from the remote node. The reason for the seperation is we can't insert
117 a node into the table without it's peer-ID. That means of course the node passed into this
118 method needs to be a properly formed Node object with a valid ID.
120 old = self.table.insertNode(n, contacted=contacted)
121 if (old and old.id != self.node.id and
122 (datetime.now() - old.lastSeen) >
123 timedelta(seconds=self.config['MIN_PING_INTERVAL'])):
124 # the bucket is full, check to see if old node is still around and if so, replace it
126 ## these are the callbacks used when we ping the oldest node in a bucket
127 def _staleNodeHandler(oldnode=old, newnode = n):
128 """ called if the pinged node never responds """
129 self.table.replaceStaleNode(old, newnode)
131 def _notStaleNodeHandler(dict, old=old):
132 """ called when we get a pong from the old node """
134 if dict['id'] == old.id:
135 self.table.justSeenNode(old.id)
137 df = old.ping(self.node.id)
138 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
140 def sendJoin(self, node, callback=None, errback=None):
144 df = node.join(self.node.id)
145 ## these are the callbacks we use when we issue a PING
146 def _pongHandler(dict, node=node, self=self, callback=callback):
147 n = self.Node(dict['rsp']['id'], dict['_krpc_sender'][0], dict['_krpc_sender'][1])
150 callback((dict['rsp']['ip_addr'], dict['rsp']['port']))
151 def _defaultPong(err, node=node, table=self.table, callback=callback, errback=errback):
152 table.nodeFailed(node)
158 df.addCallbacks(_pongHandler,_defaultPong)
160 def findCloseNodes(self, callback=lambda a: None, errback = None):
162 This does a findNode on the ID one away from our own.
163 This will allow us to populate our table with nodes on our network closest to our own.
164 This is called as soon as we start up with an empty table
166 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
167 self.findNode(id, callback, errback)
169 def refreshTable(self, force=0):
171 force=1 will refresh table regardless of last bucket access time
176 for bucket in self.table.buckets:
177 if force or (datetime.now() - bucket.lastAccessed >
178 timedelta(seconds=self.config['BUCKET_STALENESS'])):
179 id = newIDInRange(bucket.min, bucket.max)
180 self.findNode(id, callback)
184 Returns (num_contacts, num_nodes)
185 num_contacts: number contacts in our routing table
186 num_nodes: number of nodes estimated in the entire dht
188 num_contacts = reduce(lambda a, b: a + len(b.l), self.table.buckets, 0)
189 num_nodes = self.config['K'] * (2**(len(self.table.buckets) - 1))
190 return (num_contacts, num_nodes)
193 """Closes the port and cancels pending later calls."""
194 self.listenport.stopListening()
196 self.next_checkpoint.cancel()
199 self.expirer.shutdown()
202 #### Remote Interface - called by remote nodes
203 def krpc_ping(self, id, _krpc_sender):
204 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
205 self.insertNode(n, contacted=0)
206 return {"id" : self.node.id}
208 def krpc_join(self, id, _krpc_sender):
209 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
210 self.insertNode(n, contacted=0)
211 return {"ip_addr" : _krpc_sender[0], "port" : _krpc_sender[1], "id" : self.node.id}
213 def krpc_find_node(self, target, id, _krpc_sender):
214 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
215 self.insertNode(n, contacted=0)
216 nodes = self.table.findNodes(target)
217 nodes = map(lambda node: node.contactInfo(), nodes)
218 token = sha(self.token_secrets[0] + _krpc_sender[0]).digest()
219 return {"nodes" : nodes, "token" : token, "id" : self.node.id}
222 ## This class provides read-only access to the DHT, valueForKey
223 ## you probably want to use this mixin and provide your own write methods
224 class KhashmirRead(KhashmirBase):
228 def valueForKey(self, key, callback, searchlocal = 1):
229 """ returns the values found for key in global table
230 callback will be called with a list of values for each peer that returns unique values
231 final callback will be an empty list - probably should change to 'more coming' arg
233 nodes = self.table.findNodes(key)
237 l = self.store.retrieveValues(key)
239 reactor.callLater(0, callback, key, l)
243 # create our search state
244 state = GetValue(self, key, callback, self.config)
245 reactor.callLater(0, state.goWithNodes, nodes, l)
247 #### Remote Interface - called by remote nodes
248 def krpc_find_value(self, key, id, _krpc_sender):
249 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
250 self.insertNode(n, contacted=0)
252 l = self.store.retrieveValues(key)
254 return {'values' : l, "id": self.node.id}
256 nodes = self.table.findNodes(key)
257 nodes = map(lambda node: node.contactInfo(), nodes)
258 return {'nodes' : nodes, "id": self.node.id}
260 ### provides a generic write method, you probably don't want to deploy something that allows
261 ### arbitrary value storage
262 class KhashmirWrite(KhashmirRead):
264 ## async, callback indicates nodes we got a response from (but no guarantee they didn't drop it on the floor)
265 def storeValueForKey(self, key, value, callback=None):
266 """ stores the value and origination time for key in the global table, returns immediately, no status
267 in this implementation, peers respond but don't indicate status to storing values
268 a key can have many values
270 def _storeValueForKey(nodes, key=key, value=value, response=callback , table=self.table):
273 def _storedValueHandler(key, value, sender):
275 response=_storedValueHandler
276 action = StoreValue(self.table, key, value, response, self.config)
277 reactor.callLater(0, action.goWithNodes, nodes)
279 # this call is asynch
280 self.findNode(key, _storeValueForKey)
282 #### Remote Interface - called by remote nodes
283 def krpc_store_value(self, key, value, token, id, _krpc_sender):
284 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
285 self.insertNode(n, contacted=0)
286 for secret in self.token_secrets:
287 this_token = sha(secret + _krpc_sender[0]).digest()
288 if token == this_token:
289 self.store.storeValue(key, value)
291 return {"id" : self.node.id}
293 # the whole shebang, for testing
294 class Khashmir(KhashmirWrite):
297 class SimpleTests(unittest.TestCase):
300 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
301 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
302 'STORE_REDUNDANCY': 3, 'MAX_FAILURES': 3,
303 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
304 'KEINITIAL_DELAY': 15, 'KE_DELAY': 1200,
305 'KE_AGE': 3600, 'SPEW': False, }
309 d = self.DHT_DEFAULTS.copy()
312 d = self.DHT_DEFAULTS.copy()
319 os.unlink(self.a.store.db)
320 os.unlink(self.b.store.db)
322 def testAddContact(self):
323 self.failUnlessEqual(len(self.a.table.buckets), 1)
324 self.failUnlessEqual(len(self.a.table.buckets[0].l), 0)
326 self.failUnlessEqual(len(self.b.table.buckets), 1)
327 self.failUnlessEqual(len(self.b.table.buckets[0].l), 0)
329 self.a.addContact('127.0.0.1', 4045)
335 self.failUnlessEqual(len(self.a.table.buckets), 1)
336 self.failUnlessEqual(len(self.a.table.buckets[0].l), 1)
337 self.failUnlessEqual(len(self.b.table.buckets), 1)
338 self.failUnlessEqual(len(self.b.table.buckets[0].l), 1)
340 def testStoreRetrieve(self):
341 self.a.addContact('127.0.0.1', 4045)
347 self.a.storeValueForKey(sha('foo').digest(), 'foobar')
354 self.a.valueForKey(sha('foo').digest(), self._cb)
363 def _cb(self, key, val):
365 self.failUnlessEqual(self.got, 1)
366 elif 'foobar' in val:
370 class MultiTest(unittest.TestCase):
374 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
375 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
376 'STORE_REDUNDANCY': 3, 'MAX_FAILURES': 3,
377 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
378 'KEINITIAL_DELAY': 15, 'KE_DELAY': 1200,
379 'KE_AGE': 3600, 'SPEW': False, }
381 def _done(self, val):
386 self.startport = 4088
387 for i in range(self.num):
388 d = self.DHT_DEFAULTS.copy()
389 d['PORT'] = self.startport + i
390 self.l.append(Khashmir(d))
395 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
396 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
397 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
404 i.findCloseNodes(self._done)
409 i.findCloseNodes(self._done)
416 os.unlink(i.store.db)
420 def testStoreRetrieve(self):
427 def _scb(key, value, result):
429 self.l[randrange(0, self.num)].storeValueForKey(K, V, _scb)
437 self.failUnlessEqual(self.got, 1)
443 self.l[randrange(0, self.num)].valueForKey(K, _rcb)