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.app = service.Application("krpc")
37 self.udp = krpc.hostbroker(self)
38 self.udp.protocol = krpc.KRPC
39 self.listenport = reactor.listenUDP(self.port, self.udp)
40 self._loadRoutingTable()
41 self.expirer = KeyExpirer(self.store, config)
42 self.refreshTable(force=1)
43 self.next_checkpoint = reactor.callLater(60, self.checkpoint, (1,))
45 def Node(self, id, host = None, port = None):
46 """Create a new node."""
47 n = self._Node(id, host, port)
49 n.conn = self.udp.connectionForAddr((n.host, n.port))
53 self.listenport.stopListening()
55 def _loadSelfNode(self, host, port):
56 id = self.store.getSelfNode()
59 return self._Node(id, host, port)
61 def checkpoint(self, auto=0):
62 self.store.saveSelfNode(self.node.id)
63 self.store.dumpRoutingTable(self.table.buckets)
66 self.next_checkpoint = reactor.callLater(randrange(int(self.config['CHECKPOINT_INTERVAL'] * .9),
67 int(self.config['CHECKPOINT_INTERVAL'] * 1.1)),
68 self.checkpoint, (1,))
70 def _loadRoutingTable(self):
72 load routing table nodes from database
73 it's usually a good idea to call refreshTable(force=1) after loading the table
75 nodes = self.store.getRoutingTable()
77 n = self.Node(rec[0], rec[1], int(rec[2]))
78 self.table.insertNode(n, contacted=0)
82 ####### LOCAL INTERFACE - use these methods!
83 def addContact(self, host, port, callback=None):
85 ping this node and add the contact info to the table on pong!
87 n = self.Node(NULL_ID, host, port)
88 self.sendPing(n, callback=callback)
90 ## this call is async!
91 def findNode(self, id, callback, errback=None):
92 """ returns the contact info for node, or the k closest nodes, from the global table """
93 # get K nodes out of local table/cache, or the node we want
94 nodes = self.table.findNodes(id)
97 d.addCallbacks(callback, errback)
99 d.addCallback(callback)
100 if len(nodes) == 1 and nodes[0].id == id :
103 # create our search state
104 state = FindNode(self, id, d.callback, self.config)
105 reactor.callLater(0, state.goWithNodes, nodes)
107 def insertNode(self, n, contacted=1):
109 insert a node in our local table, pinging oldest contact in bucket, if necessary
111 If all you have is a host/port, then use addContact, which calls this method after
112 receiving the PONG from the remote node. The reason for the seperation is we can't insert
113 a node into the table without it's peer-ID. That means of course the node passed into this
114 method needs to be a properly formed Node object with a valid ID.
116 old = self.table.insertNode(n, contacted=contacted)
117 if (old and old.id != self.node.id and
118 (datetime.now() - old.lastSeen) >
119 timedelta(seconds=self.config['MIN_PING_INTERVAL'])):
120 # the bucket is full, check to see if old node is still around and if so, replace it
122 ## these are the callbacks used when we ping the oldest node in a bucket
123 def _staleNodeHandler(oldnode=old, newnode = n):
124 """ called if the pinged node never responds """
125 self.table.replaceStaleNode(old, newnode)
127 def _notStaleNodeHandler(dict, old=old):
128 """ called when we get a pong from the old node """
130 if dict['id'] == old.id:
131 self.table.justSeenNode(old.id)
133 df = old.ping(self.node.id)
134 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
136 def sendPing(self, node, callback=None):
140 df = node.ping(self.node.id)
141 ## these are the callbacks we use when we issue a PING
142 def _pongHandler(dict, node=node, self=self, callback=callback):
143 n = self.Node(dict['rsp']['id'], dict['_krpc_sender'][0], dict['_krpc_sender'][1])
147 def _defaultPong(err, node=node, table=self.table, callback=callback):
148 table.nodeFailed(node)
152 df.addCallbacks(_pongHandler,_defaultPong)
154 def findCloseNodes(self, callback=lambda a: None):
156 This does a findNode on the ID one away from our own.
157 This will allow us to populate our table with nodes on our network closest to our own.
158 This is called as soon as we start up with an empty table
160 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
161 self.findNode(id, callback)
163 def refreshTable(self, force=0):
165 force=1 will refresh table regardless of last bucket access time
170 for bucket in self.table.buckets:
171 if force or (datetime.now() - bucket.lastAccessed >
172 timedelta(seconds=self.config['BUCKET_STALENESS'])):
173 id = newIDInRange(bucket.min, bucket.max)
174 self.findNode(id, callback)
178 Returns (num_contacts, num_nodes)
179 num_contacts: number contacts in our routing table
180 num_nodes: number of nodes estimated in the entire dht
182 num_contacts = reduce(lambda a, b: a + len(b.l), self.table.buckets, 0)
183 num_nodes = self.config['K'] * (2**(len(self.table.buckets) - 1))
184 return (num_contacts, num_nodes)
187 """Closes the port and cancels pending later calls."""
188 self.listenport.stopListening()
190 self.next_checkpoint.cancel()
193 self.expirer.shutdown()
196 #### Remote Interface - called by remote nodes
197 def krpc_ping(self, id, _krpc_sender):
198 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
199 self.insertNode(n, contacted=0)
200 return {"id" : self.node.id}
202 def krpc_find_node(self, target, id, _krpc_sender):
203 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
204 self.insertNode(n, contacted=0)
205 nodes = self.table.findNodes(target)
206 nodes = map(lambda node: node.senderDict(), nodes)
207 return {"nodes" : nodes, "id" : self.node.id}
210 ## This class provides read-only access to the DHT, valueForKey
211 ## you probably want to use this mixin and provide your own write methods
212 class KhashmirRead(KhashmirBase):
216 def valueForKey(self, key, callback, searchlocal = 1):
217 """ returns the values found for key in global table
218 callback will be called with a list of values for each peer that returns unique values
219 final callback will be an empty list - probably should change to 'more coming' arg
221 nodes = self.table.findNodes(key)
225 l = self.store.retrieveValues(key)
227 reactor.callLater(0, callback, key, l)
231 # create our search state
232 state = GetValue(self, key, callback, self.config)
233 reactor.callLater(0, state.goWithNodes, nodes, l)
235 #### Remote Interface - called by remote nodes
236 def krpc_find_value(self, key, id, _krpc_sender):
237 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
238 self.insertNode(n, contacted=0)
240 l = self.store.retrieveValues(key)
242 return {'values' : l, "id": self.node.id}
244 nodes = self.table.findNodes(key)
245 nodes = map(lambda node: node.senderDict(), nodes)
246 return {'nodes' : nodes, "id": self.node.id}
248 ### provides a generic write method, you probably don't want to deploy something that allows
249 ### arbitrary value storage
250 class KhashmirWrite(KhashmirRead):
252 ## async, callback indicates nodes we got a response from (but no guarantee they didn't drop it on the floor)
253 def storeValueForKey(self, key, value, callback=None):
254 """ stores the value for key in the global table, returns immediately, no status
255 in this implementation, peers respond but don't indicate status to storing values
256 a key can have many values
258 def _storeValueForKey(nodes, key=key, value=value, response=callback , table=self.table):
261 def _storedValueHandler(key, value, sender):
263 response=_storedValueHandler
264 action = StoreValue(self.table, key, value, response, self.config)
265 reactor.callLater(0, action.goWithNodes, nodes)
267 # this call is asynch
268 self.findNode(key, _storeValueForKey)
270 #### Remote Interface - called by remote nodes
271 def krpc_store_value(self, key, value, id, _krpc_sender):
272 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
273 self.insertNode(n, contacted=0)
274 self.store.storeValue(key, value)
275 return {"id" : self.node.id}
277 # the whole shebang, for testing
278 class Khashmir(KhashmirWrite):
281 class SimpleTests(unittest.TestCase):
284 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
285 'CHECKPOINT_INTERVAL': 900, 'CONCURRENT_REQS': 4,
286 'STORE_REDUNDANCY': 3, 'MAX_FAILURES': 3,
287 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
288 'KEINITIAL_DELAY': 15, 'KE_DELAY': 1200,
293 d = self.DHT_DEFAULTS.copy()
296 d = self.DHT_DEFAULTS.copy()
303 os.unlink(self.a.store.db)
304 os.unlink(self.b.store.db)
306 def testAddContact(self):
307 self.assertEqual(len(self.a.table.buckets), 1)
308 self.assertEqual(len(self.a.table.buckets[0].l), 0)
310 self.assertEqual(len(self.b.table.buckets), 1)
311 self.assertEqual(len(self.b.table.buckets[0].l), 0)
313 self.a.addContact('127.0.0.1', 4045)
319 self.assertEqual(len(self.a.table.buckets), 1)
320 self.assertEqual(len(self.a.table.buckets[0].l), 1)
321 self.assertEqual(len(self.b.table.buckets), 1)
322 self.assertEqual(len(self.b.table.buckets[0].l), 1)
324 def testStoreRetrieve(self):
325 self.a.addContact('127.0.0.1', 4045)
331 self.a.storeValueForKey(sha('foo').digest(), 'foobar')
338 self.a.valueForKey(sha('foo').digest(), self._cb)
347 def _cb(self, key, val):
349 self.assertEqual(self.got, 1)
350 elif 'foobar' in val:
354 class MultiTest(unittest.TestCase):
358 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
359 'CHECKPOINT_INTERVAL': 900, 'CONCURRENT_REQS': 4,
360 'STORE_REDUNDANCY': 3, 'MAX_FAILURES': 3,
361 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
362 'KEINITIAL_DELAY': 15, 'KE_DELAY': 1200,
365 def _done(self, val):
370 self.startport = 4088
371 for i in range(self.num):
372 d = self.DHT_DEFAULTS.copy()
373 d['PORT'] = self.startport + i
374 self.l.append(Khashmir(d))
379 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
380 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
381 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
388 i.findCloseNodes(self._done)
393 i.findCloseNodes(self._done)
400 os.unlink(i.store.db)
404 def testStoreRetrieve(self):
411 def _scb(key, value, result):
413 self.l[randrange(0, self.num)].storeValueForKey(K, V, _scb)
421 self.assertEqual(self.got, 1)
427 self.l[randrange(0, self.num)].valueForKey(K, _rcb)