1 ## Copyright 2002-2004 Andrew Loewenstern, All Rights Reserved
2 # see LICENSE.txt for license information
4 """The main Khashmir program."""
7 warnings.simplefilter("ignore", DeprecationWarning)
9 from datetime import datetime, timedelta
10 from random import randrange, shuffle
14 from twisted.internet.defer import Deferred
15 from twisted.internet import protocol, reactor
16 from twisted.trial import unittest
19 from ktable import KTable
20 from knode import KNodeBase, KNodeRead, KNodeWrite, NULL_ID
21 from khash import newID, newIDInRange
22 from actions import FindNode, FindValue, GetValue, StoreValue
23 from stats import StatsLogger
26 class KhashmirBase(protocol.Factory):
27 """The base Khashmir class, with base functionality and find node, no key-value mappings.
29 @type _Node: L{node.Node}
30 @ivar _Node: the knode implementation to use for this class of DHT
31 @type config: C{dictionary}
32 @ivar config: the configuration parameters for the DHT
34 @ivar port: the port to listen on
36 @ivar store: the database to store nodes and key/value pairs in
37 @type node: L{node.Node}
39 @type table: L{ktable.KTable}
40 @ivar table: the routing table
41 @type token_secrets: C{list} of C{string}
42 @ivar token_secrets: the current secrets to use to create tokens
43 @type stats: L{stats.StatsLogger}
44 @ivar stats: the statistics gatherer
45 @type udp: L{krpc.hostbroker}
46 @ivar udp: the factory for the KRPC protocol
47 @type listenport: L{twisted.internet.interfaces.IListeningPort}
48 @ivar listenport: the UDP listening port
49 @type next_checkpoint: L{twisted.internet.interfaces.IDelayedCall}
50 @ivar next_checkpoint: the delayed call for the next checkpoint
55 def __init__(self, config, cache_dir='/tmp'):
56 """Initialize the Khashmir class and call the L{setup} method.
58 @type config: C{dictionary}
59 @param config: the configuration parameters for the DHT
60 @type cache_dir: C{string}
61 @param cache_dir: the directory to store all files in
62 (optional, defaults to the /tmp directory)
65 self.setup(config, cache_dir)
67 def setup(self, config, cache_dir):
68 """Setup all the Khashmir sub-modules.
70 @type config: C{dictionary}
71 @param config: the configuration parameters for the DHT
72 @type cache_dir: C{string}
73 @param cache_dir: the directory to store all files in
76 self.port = config['PORT']
77 self.store = DB(os.path.join(cache_dir, 'khashmir.' + str(self.port) + '.db'))
78 self.node = self._loadSelfNode('', self.port)
79 self.table = KTable(self.node, config)
80 self.token_secrets = [newID()]
81 self.stats = StatsLogger(self.table, self.store, self.config)
84 self.udp = krpc.hostbroker(self, self.stats, config)
85 self.udp.protocol = krpc.KRPC
86 self.listenport = reactor.listenUDP(self.port, self.udp)
88 # Load the routing table and begin checkpointing
89 self._loadRoutingTable()
90 self.refreshTable(force = True)
91 self.next_checkpoint = reactor.callLater(60, self.checkpoint)
93 def Node(self, id, host = None, port = None):
96 @see: L{node.Node.__init__}
98 n = self._Node(id, host, port)
100 n.conn = self.udp.connectionForAddr((n.host, n.port))
104 """Stop listening for packets."""
105 self.listenport.stopListening()
107 def _loadSelfNode(self, host, port):
108 """Create this node, loading any previously saved one."""
109 id = self.store.getSelfNode()
112 return self._Node(id, host, port)
114 def checkpoint(self):
115 """Perform some periodic maintenance operations."""
116 # Create a new token secret
117 self.token_secrets.insert(0, newID())
118 if len(self.token_secrets) > 3:
119 self.token_secrets.pop()
121 # Save some parameters for reloading
122 self.store.saveSelfNode(self.node.id)
123 self.store.dumpRoutingTable(self.table.buckets)
126 self.store.expireValues(self.config['KEY_EXPIRE'])
129 self.next_checkpoint = reactor.callLater(randrange(int(self.config['CHECKPOINT_INTERVAL'] * .9),
130 int(self.config['CHECKPOINT_INTERVAL'] * 1.1)),
133 def _loadRoutingTable(self):
134 """Load the previous routing table nodes from the database.
136 It's usually a good idea to call refreshTable(force = True) after
139 nodes = self.store.getRoutingTable()
141 n = self.Node(rec[0], rec[1], int(rec[2]))
142 self.table.insertNode(n, contacted = False)
145 def addContact(self, host, port, callback=None, errback=None):
146 """Ping this node and add the contact info to the table on pong.
148 @type host: C{string}
149 @param host: the IP address of the node to contact
151 @param port:the port of the node to contact
152 @type callback: C{method}
153 @param callback: the method to call with the results, it must take 1
154 parameter, the contact info returned by the node
155 (optional, defaults to doing nothing with the results)
156 @type errback: C{method}
157 @param errback: the method to call if an error occurs
158 (optional, defaults to calling the callback with None)
160 n = self.Node(NULL_ID, host, port)
161 self.sendJoin(n, callback=callback, errback=errback)
163 def findNode(self, id, callback, errback=None):
164 """Find the contact info for the K closest nodes in the global table.
167 @param id: the target ID to find the K closest nodes of
168 @type callback: C{method}
169 @param callback: the method to call with the results, it must take 1
170 parameter, the list of K closest nodes
171 @type errback: C{method}
172 @param errback: the method to call if an error occurs
173 (optional, defaults to doing nothing when an error occurs)
175 # Get K nodes out of local table/cache
176 nodes = self.table.findNodes(id)
179 d.addCallbacks(callback, errback)
181 d.addCallback(callback)
183 # If the target ID was found
184 if len(nodes) == 1 and nodes[0].id == id:
187 # Start the finding nodes action
188 state = FindNode(self, id, d.callback, self.config)
189 reactor.callLater(0, state.goWithNodes, nodes)
191 def insertNode(self, node, contacted = True):
192 """Try to insert a node in our local table, pinging oldest contact if necessary.
194 If all you have is a host/port, then use L{addContact}, which calls this
195 method after receiving the PONG from the remote node. The reason for
196 the seperation is we can't insert a node into the table without its
197 node ID. That means of course the node passed into this method needs
198 to be a properly formed Node object with a valid ID.
200 @type node: L{node.Node}
201 @param node: the new node to try and insert
202 @type contacted: C{boolean}
203 @param contacted: whether the new node is known to be good, i.e.
204 responded to a request (optional, defaults to True)
206 old = self.table.insertNode(node, contacted=contacted)
207 if (old and old.id != self.node.id and
208 (datetime.now() - old.lastSeen) >
209 timedelta(seconds=self.config['MIN_PING_INTERVAL'])):
211 def _staleNodeHandler(oldnode = old, newnode = node):
212 """The pinged node never responded, so replace it."""
213 self.table.replaceStaleNode(oldnode, newnode)
215 def _notStaleNodeHandler(dict, old=old):
216 """Got a pong from the old node, so update it."""
218 if dict['id'] == old.id:
219 self.table.justSeenNode(old.id)
221 # Bucket is full, check to see if old node is still available
222 df = old.ping(self.node.id)
223 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
225 def sendJoin(self, node, callback=None, errback=None):
226 """Join the DHT by pinging a bootstrap node.
228 @type node: L{node.Node}
229 @param node: the node to send the join to
230 @type callback: C{method}
231 @param callback: the method to call with the results, it must take 1
232 parameter, the contact info returned by the node
233 (optional, defaults to doing nothing with the results)
234 @type errback: C{method}
235 @param errback: the method to call if an error occurs
236 (optional, defaults to calling the callback with None)
239 def _pongHandler(dict, node=node, self=self, callback=callback):
240 """Node responded properly, callback with response."""
241 n = self.Node(dict['rsp']['id'], dict['_krpc_sender'][0], dict['_krpc_sender'][1])
244 callback((dict['rsp']['ip_addr'], dict['rsp']['port']))
246 def _defaultPong(err, node=node, table=self.table, callback=callback, errback=errback):
247 """Error occurred, fail node and errback or callback with error."""
248 table.nodeFailed(node)
254 df = node.join(self.node.id)
255 df.addCallbacks(_pongHandler, _defaultPong)
257 def findCloseNodes(self, callback=lambda a: None, errback = None):
258 """Perform a findNode on the ID one away from our own.
260 This will allow us to populate our table with nodes on our network
261 closest to our own. This is called as soon as we start up with an
264 @type callback: C{method}
265 @param callback: the method to call with the results, it must take 1
266 parameter, the list of K closest nodes
267 (optional, defaults to doing nothing with the results)
268 @type errback: C{method}
269 @param errback: the method to call if an error occurs
270 (optional, defaults to doing nothing when an error occurs)
272 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
273 self.findNode(id, callback, errback)
275 def refreshTable(self, force = False):
276 """Check all the buckets for those that need refreshing.
278 @param force: refresh all buckets regardless of last bucket access time
279 (optional, defaults to False)
284 for bucket in self.table.buckets:
285 if force or (datetime.now() - bucket.lastAccessed >
286 timedelta(seconds=self.config['BUCKET_STALENESS'])):
287 # Choose a random ID in the bucket and try and find it
288 id = newIDInRange(bucket.min, bucket.max)
289 self.findNode(id, callback)
292 """Closes the port and cancels pending later calls."""
293 self.listenport.stopListening()
295 self.next_checkpoint.cancel()
301 """Gather the statistics for the DHT."""
302 return self.stats.gather()
305 def krpc_ping(self, id, _krpc_sender):
309 @param id: the node ID of the sender node
310 @type _krpc_sender: (C{string}, C{int})
311 @param _krpc_sender: the sender node's IP address and port
313 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
314 self.insertNode(n, contacted = False)
316 return {"id" : self.node.id}
318 def krpc_join(self, id, _krpc_sender):
319 """Add the node by responding with its address and port.
322 @param id: the node ID of the sender node
323 @type _krpc_sender: (C{string}, C{int})
324 @param _krpc_sender: the sender node's IP address and port
326 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
327 self.insertNode(n, contacted = False)
329 return {"ip_addr" : _krpc_sender[0], "port" : _krpc_sender[1], "id" : self.node.id}
331 def krpc_find_node(self, target, id, _krpc_sender):
332 """Find the K closest nodes to the target in the local routing table.
334 @type target: C{string}
335 @param target: the target ID to find nodes for
337 @param id: the node ID of the sender node
338 @type _krpc_sender: (C{string}, C{int})
339 @param _krpc_sender: the sender node's IP address and port
341 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
342 self.insertNode(n, contacted = False)
344 nodes = self.table.findNodes(target)
345 nodes = map(lambda node: node.contactInfo(), nodes)
346 token = sha(self.token_secrets[0] + _krpc_sender[0]).digest()
347 return {"nodes" : nodes, "token" : token, "id" : self.node.id}
350 class KhashmirRead(KhashmirBase):
351 """The read-only Khashmir class, which can only retrieve (not store) key/value mappings."""
356 def findValue(self, key, callback, errback=None):
357 """Get the nodes that have values for the key from the global table.
360 @param key: the target key to find the values for
361 @type callback: C{method}
362 @param callback: the method to call with the results, it must take 1
363 parameter, the list of nodes with values
364 @type errback: C{method}
365 @param errback: the method to call if an error occurs
366 (optional, defaults to doing nothing when an error occurs)
368 # Get K nodes out of local table/cache
369 nodes = self.table.findNodes(key)
372 d.addCallbacks(callback, errback)
374 d.addCallback(callback)
376 # Search for others starting with the locally found ones
377 state = FindValue(self, key, d.callback, self.config)
378 reactor.callLater(0, state.goWithNodes, nodes)
380 def valueForKey(self, key, callback, searchlocal = True):
381 """Get the values found for key in global table.
383 Callback will be called with a list of values for each peer that
384 returns unique values. The final callback will be an empty list.
387 @param key: the target key to get the values for
388 @type callback: C{method}
389 @param callback: the method to call with the results, it must take 2
390 parameters: the key, and the values found
391 @type searchlocal: C{boolean}
392 @param searchlocal: whether to also look for any local values
394 # Get any local values
396 l = self.store.retrieveValues(key)
398 reactor.callLater(0, callback, key, l)
402 def _getValueForKey(nodes, key=key, local_values=l, response=callback, self=self):
403 """Use the found nodes to send requests for values to."""
404 state = GetValue(self, key, local_values, self.config['RETRIEVE_VALUES'], response, self.config)
405 reactor.callLater(0, state.goWithNodes, nodes)
407 # First lookup nodes that have values for the key
408 self.findValue(key, _getValueForKey)
411 def krpc_find_value(self, key, id, _krpc_sender):
412 """Find the number of values stored locally for the key, and the K closest nodes.
415 @param key: the target key to find the values and nodes for
417 @param id: the node ID of the sender node
418 @type _krpc_sender: (C{string}, C{int})
419 @param _krpc_sender: the sender node's IP address and port
421 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
422 self.insertNode(n, contacted = False)
424 nodes = self.table.findNodes(key)
425 nodes = map(lambda node: node.contactInfo(), nodes)
426 num_values = self.store.countValues(key)
427 return {'nodes' : nodes, 'num' : num_values, "id": self.node.id}
429 def krpc_get_value(self, key, num, id, _krpc_sender):
430 """Retrieve the values stored locally for the key.
433 @param key: the target key to retrieve the values for
435 @param num: the maximum number of values to retrieve, or 0 to
438 @param id: the node ID of the sender node
439 @type _krpc_sender: (C{string}, C{int})
440 @param _krpc_sender: the sender node's IP address and port
442 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
443 self.insertNode(n, contacted = False)
445 l = self.store.retrieveValues(key)
446 if num == 0 or num >= len(l):
447 return {'values' : l, "id": self.node.id}
450 return {'values' : l[:num], "id": self.node.id}
453 class KhashmirWrite(KhashmirRead):
454 """The read-write Khashmir class, which can store and retrieve key/value mappings."""
459 def storeValueForKey(self, key, value, callback=None):
460 """Stores the value for the key in the global table.
462 No status in this implementation, peers respond but don't indicate
463 status of storing values.
466 @param key: the target key to store the value for
467 @type value: C{string}
468 @param value: the value to store with the key
469 @type callback: C{method}
470 @param callback: the method to call with the results, it must take 3
471 parameters: the key, the value stored, and the result of the store
472 (optional, defaults to doing nothing with the results)
474 def _storeValueForKey(nodes, key=key, value=value, response=callback, self=self):
475 """Use the returned K closest nodes to store the key at."""
477 def _storedValueHandler(key, value, sender):
478 """Default callback that does nothing."""
480 response = _storedValueHandler
481 action = StoreValue(self, key, value, self.config['STORE_REDUNDANCY'], response, self.config)
482 reactor.callLater(0, action.goWithNodes, nodes)
484 # First find the K closest nodes to operate on.
485 self.findNode(key, _storeValueForKey)
488 def krpc_store_value(self, key, value, token, id, _krpc_sender):
489 """Store the value locally with the key.
492 @param key: the target key to store the value for
493 @type value: C{string}
494 @param value: the value to store with the key
495 @param token: the token to confirm that this peer contacted us previously
497 @param id: the node ID of the sender node
498 @type _krpc_sender: (C{string}, C{int})
499 @param _krpc_sender: the sender node's IP address and port
501 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
502 self.insertNode(n, contacted = False)
503 for secret in self.token_secrets:
504 this_token = sha(secret + _krpc_sender[0]).digest()
505 if token == this_token:
506 self.store.storeValue(key, value)
507 return {"id" : self.node.id}
508 raise krpc.KrpcError, (krpc.KRPC_ERROR_INVALID_TOKEN, 'token is invalid, do a find_nodes to get a fresh one')
511 class Khashmir(KhashmirWrite):
512 """The default Khashmir class (currently the read-write L{KhashmirWrite})."""
516 class SimpleTests(unittest.TestCase):
519 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
520 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
521 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
523 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
524 'KEY_EXPIRE': 3600, 'SPEW': False, }
527 d = self.DHT_DEFAULTS.copy()
530 d = self.DHT_DEFAULTS.copy()
537 os.unlink(self.a.store.db)
538 os.unlink(self.b.store.db)
540 def testAddContact(self):
541 self.failUnlessEqual(len(self.a.table.buckets), 1)
542 self.failUnlessEqual(len(self.a.table.buckets[0].l), 0)
544 self.failUnlessEqual(len(self.b.table.buckets), 1)
545 self.failUnlessEqual(len(self.b.table.buckets[0].l), 0)
547 self.a.addContact('127.0.0.1', 4045)
553 self.failUnlessEqual(len(self.a.table.buckets), 1)
554 self.failUnlessEqual(len(self.a.table.buckets[0].l), 1)
555 self.failUnlessEqual(len(self.b.table.buckets), 1)
556 self.failUnlessEqual(len(self.b.table.buckets[0].l), 1)
558 def testStoreRetrieve(self):
559 self.a.addContact('127.0.0.1', 4045)
565 self.a.storeValueForKey(sha('foo').digest(), 'foobar')
572 self.a.valueForKey(sha('foo').digest(), self._cb)
581 def _cb(self, key, val):
583 self.failUnlessEqual(self.got, 1)
584 elif 'foobar' in val:
588 class MultiTest(unittest.TestCase):
592 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
593 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
594 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
596 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
597 'KEY_EXPIRE': 3600, 'SPEW': False, }
599 def _done(self, val):
604 self.startport = 4088
605 for i in range(self.num):
606 d = self.DHT_DEFAULTS.copy()
607 d['PORT'] = self.startport + i
608 self.l.append(Khashmir(d))
613 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
614 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
615 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
622 i.findCloseNodes(self._done)
627 i.findCloseNodes(self._done)
634 os.unlink(i.store.db)
638 def testStoreRetrieve(self):
645 def _scb(key, value, result):
647 self.l[randrange(0, self.num)].storeValueForKey(K, V, _scb)
655 self.failUnlessEqual(self.got, 1)
661 self.l[randrange(0, self.num)].valueForKey(K, _rcb)