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
15 from twisted.internet.defer import Deferred
16 from twisted.internet import protocol, reactor
17 from twisted.python import log
18 from twisted.trial import unittest
21 from ktable import KTable
22 from knode import KNodeBase, KNodeRead, KNodeWrite, NULL_ID
23 from khash import newID, newIDInRange
24 from actions import FindNode, FindValue, GetValue, StoreValue
25 from stats import StatsLogger
28 class KhashmirBase(protocol.Factory):
29 """The base Khashmir class, with base functionality and find node, no key-value mappings.
31 @type _Node: L{node.Node}
32 @ivar _Node: the knode implementation to use for this class of DHT
33 @type config: C{dictionary}
34 @ivar config: the configuration parameters for the DHT
36 @ivar port: the port to listen on
38 @ivar store: the database to store nodes and key/value pairs in
39 @type node: L{node.Node}
41 @type table: L{ktable.KTable}
42 @ivar table: the routing table
43 @type token_secrets: C{list} of C{string}
44 @ivar token_secrets: the current secrets to use to create tokens
45 @type stats: L{stats.StatsLogger}
46 @ivar stats: the statistics gatherer
47 @type udp: L{krpc.hostbroker}
48 @ivar udp: the factory for the KRPC protocol
49 @type listenport: L{twisted.internet.interfaces.IListeningPort}
50 @ivar listenport: the UDP listening port
51 @type next_checkpoint: L{twisted.internet.interfaces.IDelayedCall}
52 @ivar next_checkpoint: the delayed call for the next checkpoint
57 def __init__(self, config, cache_dir='/tmp'):
58 """Initialize the Khashmir class and call the L{setup} method.
60 @type config: C{dictionary}
61 @param config: the configuration parameters for the DHT
62 @type cache_dir: C{string}
63 @param cache_dir: the directory to store all files in
64 (optional, defaults to the /tmp directory)
67 self.setup(config, cache_dir)
69 def setup(self, config, cache_dir):
70 """Setup all the Khashmir sub-modules.
72 @type config: C{dictionary}
73 @param config: the configuration parameters for the DHT
74 @type cache_dir: C{string}
75 @param cache_dir: the directory to store all files in
78 self.port = config['PORT']
79 self.store = DB(os.path.join(cache_dir, 'khashmir.' + str(self.port) + '.db'))
80 self.node = self._loadSelfNode('', self.port)
81 self.table = KTable(self.node, config)
82 self.token_secrets = [newID()]
83 self.stats = StatsLogger(self.table, self.store, self.config)
86 self.udp = krpc.hostbroker(self, self.stats, config)
87 self.udp.protocol = krpc.KRPC
88 self.listenport = reactor.listenUDP(self.port, self.udp)
90 # Load the routing table and begin checkpointing
91 self._loadRoutingTable()
92 self.refreshTable(force = True)
93 self.next_checkpoint = reactor.callLater(60, self.checkpoint)
95 def Node(self, id, host = None, port = None):
98 @see: L{node.Node.__init__}
100 n = self._Node(id, host, port)
102 n.conn = self.udp.connectionForAddr((n.host, n.port))
106 """Stop listening for packets."""
107 self.listenport.stopListening()
109 def _loadSelfNode(self, host, port):
110 """Create this node, loading any previously saved one."""
111 id = self.store.getSelfNode()
114 return self._Node(id, host, port)
116 def checkpoint(self):
117 """Perform some periodic maintenance operations."""
118 # Create a new token secret
119 self.token_secrets.insert(0, newID())
120 if len(self.token_secrets) > 3:
121 self.token_secrets.pop()
123 # Save some parameters for reloading
124 self.store.saveSelfNode(self.node.id)
125 self.store.dumpRoutingTable(self.table.buckets)
128 self.store.expireValues(self.config['KEY_EXPIRE'])
131 self.next_checkpoint = reactor.callLater(randrange(int(self.config['CHECKPOINT_INTERVAL'] * .9),
132 int(self.config['CHECKPOINT_INTERVAL'] * 1.1)),
135 def _loadRoutingTable(self):
136 """Load the previous routing table nodes from the database.
138 It's usually a good idea to call refreshTable(force = True) after
141 nodes = self.store.getRoutingTable()
143 n = self.Node(rec[0], rec[1], int(rec[2]))
144 self.table.insertNode(n, contacted = False)
147 def addContact(self, host, port, callback=None, errback=None):
148 """Ping this node and add the contact info to the table on pong.
150 @type host: C{string}
151 @param host: the IP address of the node to contact
153 @param port:the port of the node to contact
154 @type callback: C{method}
155 @param callback: the method to call with the results, it must take 1
156 parameter, the contact info returned by the node
157 (optional, defaults to doing nothing with the results)
158 @type errback: C{method}
159 @param errback: the method to call if an error occurs
160 (optional, defaults to calling the callback with None)
162 n = self.Node(NULL_ID, host, port)
163 self.sendJoin(n, callback=callback, errback=errback)
165 def findNode(self, id, callback, errback=None):
166 """Find the contact info for the K closest nodes in the global table.
169 @param id: the target ID to find the K closest nodes of
170 @type callback: C{method}
171 @param callback: the method to call with the results, it must take 1
172 parameter, the list of K closest nodes
173 @type errback: C{method}
174 @param errback: the method to call if an error occurs
175 (optional, defaults to doing nothing when an error occurs)
177 # Get K nodes out of local table/cache
178 nodes = self.table.findNodes(id)
179 nodes = [copy(node) for node in nodes]
182 d.addCallbacks(callback, errback)
184 d.addCallback(callback)
186 # If the target ID was found
187 if len(nodes) == 1 and nodes[0].id == id:
190 # Start the finding nodes action
191 state = FindNode(self, id, d.callback, self.config, self.stats)
192 reactor.callLater(0, state.goWithNodes, nodes)
194 def insertNode(self, node, contacted = True):
195 """Try to insert a node in our local table, pinging oldest contact if necessary.
197 If all you have is a host/port, then use L{addContact}, which calls this
198 method after receiving the PONG from the remote node. The reason for
199 the seperation is we can't insert a node into the table without its
200 node ID. That means of course the node passed into this method needs
201 to be a properly formed Node object with a valid ID.
203 @type node: L{node.Node}
204 @param node: the new node to try and insert
205 @type contacted: C{boolean}
206 @param contacted: whether the new node is known to be good, i.e.
207 responded to a request (optional, defaults to True)
209 old = self.table.insertNode(node, contacted=contacted)
210 if (old and old.id != self.node.id and
211 (datetime.now() - old.lastSeen) >
212 timedelta(seconds=self.config['MIN_PING_INTERVAL'])):
214 def _staleNodeHandler(err, oldnode = old, newnode = node, self = self):
215 """The pinged node never responded, so replace it."""
216 log.msg("ping failed (%s) %s/%s" % (self.config['PORT'], oldnode.host, oldnode.port))
218 self.table.replaceStaleNode(oldnode, newnode)
220 def _notStaleNodeHandler(dict, old=old, self=self):
221 """Got a pong from the old node, so update it."""
222 if dict['id'] == old.id:
223 self.table.justSeenNode(old.id)
225 # Bucket is full, check to see if old node is still available
226 self.stats.startedAction('ping')
227 df = old.ping(self.node.id)
228 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
230 def sendJoin(self, node, callback=None, errback=None):
231 """Join the DHT by pinging a bootstrap node.
233 @type node: L{node.Node}
234 @param node: the node to send the join to
235 @type callback: C{method}
236 @param callback: the method to call with the results, it must take 1
237 parameter, the contact info returned by the node
238 (optional, defaults to doing nothing with the results)
239 @type errback: C{method}
240 @param errback: the method to call if an error occurs
241 (optional, defaults to calling the callback with None)
244 def _pongHandler(dict, node=node, self=self, callback=callback):
245 """Node responded properly, callback with response."""
246 n = self.Node(dict['id'], dict['_krpc_sender'][0], dict['_krpc_sender'][1])
249 callback((dict['ip_addr'], dict['port']))
251 def _defaultPong(err, node=node, self=self, callback=callback, errback=errback):
252 """Error occurred, fail node and errback or callback with error."""
253 log.msg("join failed (%s) %s/%s" % (self.config['PORT'], node.host, node.port))
255 self.table.nodeFailed(node)
261 self.stats.startedAction('join')
262 df = node.join(self.node.id)
263 df.addCallbacks(_pongHandler, _defaultPong)
265 def findCloseNodes(self, callback=lambda a: None, errback = None):
266 """Perform a findNode on the ID one away from our own.
268 This will allow us to populate our table with nodes on our network
269 closest to our own. This is called as soon as we start up with an
272 @type callback: C{method}
273 @param callback: the method to call with the results, it must take 1
274 parameter, the list of K closest nodes
275 (optional, defaults to doing nothing with the results)
276 @type errback: C{method}
277 @param errback: the method to call if an error occurs
278 (optional, defaults to doing nothing when an error occurs)
280 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
281 self.findNode(id, callback, errback)
283 def refreshTable(self, force = False):
284 """Check all the buckets for those that need refreshing.
286 @param force: refresh all buckets regardless of last bucket access time
287 (optional, defaults to False)
292 for bucket in self.table.buckets:
293 if force or (datetime.now() - bucket.lastAccessed >
294 timedelta(seconds=self.config['BUCKET_STALENESS'])):
295 # Choose a random ID in the bucket and try and find it
296 id = newIDInRange(bucket.min, bucket.max)
297 self.findNode(id, callback)
300 """Closes the port and cancels pending later calls."""
301 self.listenport.stopListening()
303 self.next_checkpoint.cancel()
309 """Gather the statistics for the DHT."""
310 return self.stats.formatHTML()
313 def krpc_ping(self, id, _krpc_sender = None):
317 @param id: the node ID of the sender node
318 @type _krpc_sender: (C{string}, C{int})
319 @param _krpc_sender: the sender node's IP address and port
321 if _krpc_sender is not None:
322 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
323 self.insertNode(n, contacted = False)
325 return {"id" : self.node.id}
327 def krpc_join(self, id, _krpc_sender = None):
328 """Add the node by responding with its address and port.
331 @param id: the node ID of the sender node
332 @type _krpc_sender: (C{string}, C{int})
333 @param _krpc_sender: the sender node's IP address and port
335 if _krpc_sender is not None:
336 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
337 self.insertNode(n, contacted = False)
339 _krpc_sender = ('127.0.0.1', self.port)
341 return {"ip_addr" : _krpc_sender[0], "port" : _krpc_sender[1], "id" : self.node.id}
343 def krpc_find_node(self, id, target, _krpc_sender = None):
344 """Find the K closest nodes to the target in the local routing table.
346 @type target: C{string}
347 @param target: the target ID to find nodes for
349 @param id: the node ID of the sender node
350 @type _krpc_sender: (C{string}, C{int})
351 @param _krpc_sender: the sender node's IP address and port
353 if _krpc_sender is not None:
354 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
355 self.insertNode(n, contacted = False)
357 _krpc_sender = ('127.0.0.1', self.port)
359 nodes = self.table.findNodes(target)
360 nodes = map(lambda node: node.contactInfo(), nodes)
361 token = sha(self.token_secrets[0] + _krpc_sender[0]).digest()
362 return {"nodes" : nodes, "token" : token, "id" : self.node.id}
365 class KhashmirRead(KhashmirBase):
366 """The read-only Khashmir class, which can only retrieve (not store) key/value mappings."""
371 def findValue(self, key, callback, errback=None):
372 """Get the nodes that have values for the key from the global table.
375 @param key: the target key to find the values for
376 @type callback: C{method}
377 @param callback: the method to call with the results, it must take 1
378 parameter, the list of nodes with values
379 @type errback: C{method}
380 @param errback: the method to call if an error occurs
381 (optional, defaults to doing nothing when an error occurs)
383 # Get K nodes out of local table/cache
384 nodes = self.table.findNodes(key)
385 nodes = [copy(node) for node in nodes]
388 d.addCallbacks(callback, errback)
390 d.addCallback(callback)
392 # Search for others starting with the locally found ones
393 state = FindValue(self, key, d.callback, self.config, self.stats)
394 reactor.callLater(0, state.goWithNodes, nodes)
396 def valueForKey(self, key, callback, searchlocal = True):
397 """Get the values found for key in global table.
399 Callback will be called with a list of values for each peer that
400 returns unique values. The final callback will be an empty list.
403 @param key: the target key to get the values for
404 @type callback: C{method}
405 @param callback: the method to call with the results, it must take 2
406 parameters: the key, and the values found
407 @type searchlocal: C{boolean}
408 @param searchlocal: whether to also look for any local values
410 # Get any local values
412 l = self.store.retrieveValues(key)
414 reactor.callLater(0, callback, key, l)
418 def _getValueForKey(nodes, key=key, local_values=l, response=callback, self=self):
419 """Use the found nodes to send requests for values to."""
420 state = GetValue(self, key, local_values, self.config['RETRIEVE_VALUES'], response, self.config, self.stats)
421 reactor.callLater(0, state.goWithNodes, nodes)
423 # First lookup nodes that have values for the key
424 self.findValue(key, _getValueForKey)
427 def krpc_find_value(self, id, key, _krpc_sender = None):
428 """Find the number of values stored locally for the key, and the K closest nodes.
431 @param key: the target key to find the values and nodes for
433 @param id: the node ID of the sender node
434 @type _krpc_sender: (C{string}, C{int})
435 @param _krpc_sender: the sender node's IP address and port
437 if _krpc_sender is not None:
438 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
439 self.insertNode(n, contacted = False)
441 nodes = self.table.findNodes(key)
442 nodes = map(lambda node: node.contactInfo(), nodes)
443 num_values = self.store.countValues(key)
444 return {'nodes' : nodes, 'num' : num_values, "id": self.node.id}
446 def krpc_get_value(self, id, key, num, _krpc_sender = None):
447 """Retrieve the values stored locally for the key.
450 @param key: the target key to retrieve the values for
452 @param num: the maximum number of values to retrieve, or 0 to
455 @param id: the node ID of the sender node
456 @type _krpc_sender: (C{string}, C{int})
457 @param _krpc_sender: the sender node's IP address and port
459 if _krpc_sender is not None:
460 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
461 self.insertNode(n, contacted = False)
463 l = self.store.retrieveValues(key)
464 if num == 0 or num >= len(l):
465 return {'values' : l, "id": self.node.id}
468 return {'values' : l[:num], "id": self.node.id}
471 class KhashmirWrite(KhashmirRead):
472 """The read-write Khashmir class, which can store and retrieve key/value mappings."""
477 def storeValueForKey(self, key, value, callback=None):
478 """Stores the value for the key in the global table.
480 No status in this implementation, peers respond but don't indicate
481 status of storing values.
484 @param key: the target key to store the value for
485 @type value: C{string}
486 @param value: the value to store with the key
487 @type callback: C{method}
488 @param callback: the method to call with the results, it must take 3
489 parameters: the key, the value stored, and the result of the store
490 (optional, defaults to doing nothing with the results)
492 def _storeValueForKey(nodes, key=key, value=value, response=callback, self=self):
493 """Use the returned K closest nodes to store the key at."""
495 def _storedValueHandler(key, value, sender):
496 """Default callback that does nothing."""
498 response = _storedValueHandler
499 action = StoreValue(self, key, value, self.config['STORE_REDUNDANCY'], response, self.config, self.stats)
500 reactor.callLater(0, action.goWithNodes, nodes)
502 # First find the K closest nodes to operate on.
503 self.findNode(key, _storeValueForKey)
506 def krpc_store_value(self, id, key, value, token, _krpc_sender = None):
507 """Store the value locally with the key.
510 @param key: the target key to store the value for
511 @type value: C{string}
512 @param value: the value to store with the key
513 @param token: the token to confirm that this peer contacted us previously
515 @param id: the node ID of the sender node
516 @type _krpc_sender: (C{string}, C{int})
517 @param _krpc_sender: the sender node's IP address and port
519 if _krpc_sender is not None:
520 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
521 self.insertNode(n, contacted = False)
523 _krpc_sender = ('127.0.0.1', self.port)
525 for secret in self.token_secrets:
526 this_token = sha(secret + _krpc_sender[0]).digest()
527 if token == this_token:
528 self.store.storeValue(key, value)
529 return {"id" : self.node.id}
530 raise krpc.KrpcError, (krpc.KRPC_ERROR_INVALID_TOKEN, 'token is invalid, do a find_nodes to get a fresh one')
533 class Khashmir(KhashmirWrite):
534 """The default Khashmir class (currently the read-write L{KhashmirWrite})."""
538 class SimpleTests(unittest.TestCase):
541 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
542 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
543 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
545 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
546 'KEY_EXPIRE': 3600, 'SPEW': False, }
549 d = self.DHT_DEFAULTS.copy()
552 d = self.DHT_DEFAULTS.copy()
559 os.unlink(self.a.store.db)
560 os.unlink(self.b.store.db)
562 def testAddContact(self):
563 self.failUnlessEqual(len(self.a.table.buckets), 1)
564 self.failUnlessEqual(len(self.a.table.buckets[0].l), 0)
566 self.failUnlessEqual(len(self.b.table.buckets), 1)
567 self.failUnlessEqual(len(self.b.table.buckets[0].l), 0)
569 self.a.addContact('127.0.0.1', 4045)
575 self.failUnlessEqual(len(self.a.table.buckets), 1)
576 self.failUnlessEqual(len(self.a.table.buckets[0].l), 1)
577 self.failUnlessEqual(len(self.b.table.buckets), 1)
578 self.failUnlessEqual(len(self.b.table.buckets[0].l), 1)
580 def testStoreRetrieve(self):
581 self.a.addContact('127.0.0.1', 4045)
587 self.a.storeValueForKey(sha('foo').digest(), 'foobar')
594 self.a.valueForKey(sha('foo').digest(), self._cb)
603 def _cb(self, key, val):
605 self.failUnlessEqual(self.got, 1)
606 elif 'foobar' in val:
610 class MultiTest(unittest.TestCase):
614 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
615 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
616 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
618 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
619 'KEY_EXPIRE': 3600, 'SPEW': False, }
621 def _done(self, val):
626 self.startport = 4088
627 for i in range(self.num):
628 d = self.DHT_DEFAULTS.copy()
629 d['PORT'] = self.startport + i
630 self.l.append(Khashmir(d))
635 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
636 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
637 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
644 i.findCloseNodes(self._done)
649 i.findCloseNodes(self._done)
656 os.unlink(i.store.db)
660 def testStoreRetrieve(self):
667 def _scb(key, value, result):
669 self.l[randrange(0, self.num)].storeValueForKey(K, V, _scb)
677 self.failUnlessEqual(self.got, 1)
683 self.l[randrange(0, self.num)].valueForKey(K, _rcb)