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)
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):
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
174 # Start with our node
175 nodes = [copy(self.node)]
177 # Start the finding nodes action
178 state = FindNode(self, id, callback, self.config, self.stats)
179 reactor.callLater(0, state.goWithNodes, nodes)
181 def insertNode(self, node, contacted = True):
182 """Try to insert a node in our local table, pinging oldest contact if necessary.
184 If all you have is a host/port, then use L{addContact}, which calls this
185 method after receiving the PONG from the remote node. The reason for
186 the seperation is we can't insert a node into the table without its
187 node ID. That means of course the node passed into this method needs
188 to be a properly formed Node object with a valid ID.
190 @type node: L{node.Node}
191 @param node: the new node to try and insert
192 @type contacted: C{boolean}
193 @param contacted: whether the new node is known to be good, i.e.
194 responded to a request (optional, defaults to True)
196 old = self.table.insertNode(node, contacted=contacted)
197 if (old and old.id != self.node.id and
198 (datetime.now() - old.lastSeen) >
199 timedelta(seconds=self.config['MIN_PING_INTERVAL'])):
201 def _staleNodeHandler(err, oldnode = old, newnode = node, self = self, start = datetime.now()):
202 """The pinged node never responded, so replace it."""
203 log.msg("ping failed (%s) %s/%s" % (self.config['PORT'], oldnode.host, oldnode.port))
205 self.stats.completedAction('ping', start)
206 self.table.replaceStaleNode(oldnode, newnode)
208 def _notStaleNodeHandler(dict, old = old, self = self, start = datetime.now()):
209 """Got a pong from the old node, so update it."""
210 self.stats.completedAction('ping', start)
211 if dict['id'] == old.id:
212 self.table.justSeenNode(old.id)
214 # Bucket is full, check to see if old node is still available
215 self.stats.startedAction('ping')
216 df = old.ping(self.node.id)
217 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
219 def sendJoin(self, node, callback=None, errback=None):
220 """Join the DHT by pinging a bootstrap node.
222 @type node: L{node.Node}
223 @param node: the node to send the join to
224 @type callback: C{method}
225 @param callback: the method to call with the results, it must take 1
226 parameter, the contact info returned by the node
227 (optional, defaults to doing nothing with the results)
228 @type errback: C{method}
229 @param errback: the method to call if an error occurs
230 (optional, defaults to calling the callback with None)
233 def _pongHandler(dict, node=node, self=self, callback=callback, start = datetime.now()):
234 """Node responded properly, callback with response."""
235 n = self.Node(dict['id'], dict['_krpc_sender'][0], dict['_krpc_sender'][1])
236 self.stats.completedAction('join', start)
239 callback((dict['ip_addr'], dict['port']))
241 def _defaultPong(err, node=node, self=self, callback=callback, errback=errback, start = datetime.now()):
242 """Error occurred, fail node and errback or callback with error."""
243 log.msg("join failed (%s) %s/%s" % (self.config['PORT'], node.host, node.port))
245 self.stats.completedAction('join', start)
246 self.table.nodeFailed(node)
252 self.stats.startedAction('join')
253 df = node.join(self.node.id)
254 df.addCallbacks(_pongHandler, _defaultPong)
256 def findCloseNodes(self, callback=lambda a: None):
257 """Perform a findNode on the ID one away from our own.
259 This will allow us to populate our table with nodes on our network
260 closest to our own. This is called as soon as we start up with an
263 @type callback: C{method}
264 @param callback: the method to call with the results, it must take 1
265 parameter, the list of K closest nodes
266 (optional, defaults to doing nothing with the results)
268 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
269 self.findNode(id, callback)
271 def refreshTable(self, force = False):
272 """Check all the buckets for those that need refreshing.
274 @param force: refresh all buckets regardless of last bucket access time
275 (optional, defaults to False)
280 for bucket in self.table.buckets:
281 if force or (datetime.now() - bucket.lastAccessed >
282 timedelta(seconds=self.config['BUCKET_STALENESS'])):
283 # Choose a random ID in the bucket and try and find it
284 id = newIDInRange(bucket.min, bucket.max)
285 self.findNode(id, callback)
288 """Closes the port and cancels pending later calls."""
289 self.listenport.stopListening()
291 self.next_checkpoint.cancel()
297 """Gather the statistics for the DHT."""
298 return self.stats.formatHTML()
301 def krpc_ping(self, id, _krpc_sender = None):
305 @param id: the node ID of the sender node
306 @type _krpc_sender: (C{string}, C{int})
307 @param _krpc_sender: the sender node's IP address and port
309 if _krpc_sender is not None:
310 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
311 self.insertNode(n, contacted = False)
313 return {"id" : self.node.id}
315 def krpc_join(self, id, _krpc_sender = None):
316 """Add the node by responding with its address and port.
319 @param id: the node ID of the sender node
320 @type _krpc_sender: (C{string}, C{int})
321 @param _krpc_sender: the sender node's IP address and port
323 if _krpc_sender is not None:
324 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
325 self.insertNode(n, contacted = False)
327 _krpc_sender = ('127.0.0.1', self.port)
329 return {"ip_addr" : _krpc_sender[0], "port" : _krpc_sender[1], "id" : self.node.id}
331 def krpc_find_node(self, id, target, _krpc_sender = None):
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 if _krpc_sender is not None:
342 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
343 self.insertNode(n, contacted = False)
345 _krpc_sender = ('127.0.0.1', self.port)
347 nodes = self.table.findNodes(target)
348 nodes = map(lambda node: node.contactInfo(), nodes)
349 token = sha(self.token_secrets[0] + _krpc_sender[0]).digest()
350 return {"nodes" : nodes, "token" : token, "id" : self.node.id}
353 class KhashmirRead(KhashmirBase):
354 """The read-only Khashmir class, which can only retrieve (not store) key/value mappings."""
359 def findValue(self, key, callback):
360 """Get the nodes that have values for the key from the global table.
363 @param key: the target key to find the values for
364 @type callback: C{method}
365 @param callback: the method to call with the results, it must take 1
366 parameter, the list of nodes with values
369 nodes = [copy(self.node)]
371 # Search for others starting with the locally found ones
372 state = FindValue(self, key, callback, self.config, self.stats)
373 reactor.callLater(0, state.goWithNodes, nodes)
375 def valueForKey(self, key, callback, searchlocal = True):
376 """Get the values found for key in global table.
378 Callback will be called with a list of values for each peer that
379 returns unique values. The final callback will be an empty list.
382 @param key: the target key to get the values for
383 @type callback: C{method}
384 @param callback: the method to call with the results, it must take 2
385 parameters: the key, and the values found
386 @type searchlocal: C{boolean}
387 @param searchlocal: whether to also look for any local values
390 def _getValueForKey(nodes, key=key, response=callback, self=self, searchlocal=searchlocal):
391 """Use the found nodes to send requests for values to."""
392 # Get any local values
394 l = self.store.retrieveValues(key)
396 node = copy(self.node)
397 node.updateNumValues(len(l))
398 nodes = nodes + [node]
400 state = GetValue(self, key, self.config['RETRIEVE_VALUES'], response, self.config, self.stats)
401 reactor.callLater(0, state.goWithNodes, nodes)
403 # First lookup nodes that have values for the key
404 self.findValue(key, _getValueForKey)
407 def krpc_find_value(self, id, key, _krpc_sender = None):
408 """Find the number of values stored locally for the key, and the K closest nodes.
411 @param key: the target key to find the values and nodes for
413 @param id: the node ID of the sender node
414 @type _krpc_sender: (C{string}, C{int})
415 @param _krpc_sender: the sender node's IP address and port
417 if _krpc_sender is not None:
418 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
419 self.insertNode(n, contacted = False)
421 nodes = self.table.findNodes(key)
422 nodes = map(lambda node: node.contactInfo(), nodes)
423 num_values = self.store.countValues(key)
424 return {'nodes' : nodes, 'num' : num_values, "id": self.node.id}
426 def krpc_get_value(self, id, key, num, _krpc_sender = None):
427 """Retrieve the values stored locally for the key.
430 @param key: the target key to retrieve the values for
432 @param num: the maximum number of values to retrieve, or 0 to
435 @param id: the node ID of the sender node
436 @type _krpc_sender: (C{string}, C{int})
437 @param _krpc_sender: the sender node's IP address and port
439 if _krpc_sender is not None:
440 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
441 self.insertNode(n, contacted = False)
443 l = self.store.retrieveValues(key)
444 if num == 0 or num >= len(l):
445 return {'values' : l, "id": self.node.id}
448 return {'values' : l[:num], "id": self.node.id}
451 class KhashmirWrite(KhashmirRead):
452 """The read-write Khashmir class, which can store and retrieve key/value mappings."""
457 def storeValueForKey(self, key, value, callback=None):
458 """Stores the value for the key in the global table.
460 No status in this implementation, peers respond but don't indicate
461 status of storing values.
464 @param key: the target key to store the value for
465 @type value: C{string}
466 @param value: the value to store with the key
467 @type callback: C{method}
468 @param callback: the method to call with the results, it must take 3
469 parameters: the key, the value stored, and the result of the store
470 (optional, defaults to doing nothing with the results)
472 def _storeValueForKey(nodes, key=key, value=value, response=callback, self=self):
473 """Use the returned K closest nodes to store the key at."""
475 def _storedValueHandler(key, value, sender):
476 """Default callback that does nothing."""
478 response = _storedValueHandler
479 action = StoreValue(self, key, value, self.config['STORE_REDUNDANCY'], response, self.config, self.stats)
480 reactor.callLater(0, action.goWithNodes, nodes)
482 # First find the K closest nodes to operate on.
483 self.findNode(key, _storeValueForKey)
486 def krpc_store_value(self, id, key, value, token, _krpc_sender = None):
487 """Store the value locally with the key.
490 @param key: the target key to store the value for
491 @type value: C{string}
492 @param value: the value to store with the key
493 @param token: the token to confirm that this peer contacted us previously
495 @param id: the node ID of the sender node
496 @type _krpc_sender: (C{string}, C{int})
497 @param _krpc_sender: the sender node's IP address and port
499 if _krpc_sender is not None:
500 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
501 self.insertNode(n, contacted = False)
503 _krpc_sender = ('127.0.0.1', self.port)
505 for secret in self.token_secrets:
506 this_token = sha(secret + _krpc_sender[0]).digest()
507 if token == this_token:
508 self.store.storeValue(key, value)
509 return {"id" : self.node.id}
510 raise krpc.KrpcError, (krpc.KRPC_ERROR_INVALID_TOKEN, 'token is invalid, do a find_nodes to get a fresh one')
513 class Khashmir(KhashmirWrite):
514 """The default Khashmir class (currently the read-write L{KhashmirWrite})."""
518 class SimpleTests(unittest.TestCase):
521 DHT_DEFAULTS = {'PORT': 9977,
522 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
523 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
525 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
526 'KEY_EXPIRE': 3600, 'SPEW': False, }
529 d = self.DHT_DEFAULTS.copy()
532 d = self.DHT_DEFAULTS.copy()
539 os.unlink(self.a.store.db)
540 os.unlink(self.b.store.db)
542 def testAddContact(self):
543 self.failUnlessEqual(len(self.a.table.buckets), 1)
544 self.failUnlessEqual(len(self.a.table.buckets[0].l), 0)
546 self.failUnlessEqual(len(self.b.table.buckets), 1)
547 self.failUnlessEqual(len(self.b.table.buckets[0].l), 0)
549 self.a.addContact('127.0.0.1', 4045)
555 self.failUnlessEqual(len(self.a.table.buckets), 1)
556 self.failUnlessEqual(len(self.a.table.buckets[0].l), 1)
557 self.failUnlessEqual(len(self.b.table.buckets), 1)
558 self.failUnlessEqual(len(self.b.table.buckets[0].l), 1)
560 def testStoreRetrieve(self):
561 self.a.addContact('127.0.0.1', 4045)
567 self.a.storeValueForKey(sha('foo').digest(), 'foobar')
574 self.a.valueForKey(sha('foo').digest(), self._cb)
583 def _cb(self, key, val):
585 self.failUnlessEqual(self.got, 1)
586 elif 'foobar' in val:
590 class MultiTest(unittest.TestCase):
594 DHT_DEFAULTS = {'PORT': 9977,
595 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
596 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
598 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
599 'KEY_EXPIRE': 3600, 'SPEW': False, }
601 def _done(self, val):
606 self.startport = 4088
607 for i in range(self.num):
608 d = self.DHT_DEFAULTS.copy()
609 d['PORT'] = self.startport + i
610 self.l.append(Khashmir(d))
615 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
616 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
617 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
624 i.findCloseNodes(self._done)
629 i.findCloseNodes(self._done)
636 os.unlink(i.store.db)
640 def testStoreRetrieve(self):
647 def _scb(key, value, result):
649 self.l[randrange(0, self.num)].storeValueForKey(K, V, _scb)
657 self.failUnlessEqual(self.got, 1)
663 self.l[randrange(0, self.num)].valueForKey(K, _rcb)