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("action ping failed on %s/%s: %s" % (oldnode.host, oldnode.port, err.getErrorMessage()))
204 self.stats.completedAction('ping', start)
205 self.table.replaceStaleNode(oldnode, newnode)
207 def _notStaleNodeHandler(dict, old = old, self = self, start = datetime.now()):
208 """Got a pong from the old node, so update it."""
209 self.stats.completedAction('ping', start)
210 if dict['id'] == old.id:
211 self.table.justSeenNode(old.id)
213 # Bucket is full, check to see if old node is still available
214 self.stats.startedAction('ping')
215 df = old.ping(self.node.id)
216 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
218 def sendJoin(self, node, callback=None, errback=None):
219 """Join the DHT by pinging a bootstrap node.
221 @type node: L{node.Node}
222 @param node: the node to send the join to
223 @type callback: C{method}
224 @param callback: the method to call with the results, it must take 1
225 parameter, the contact info returned by the node
226 (optional, defaults to doing nothing with the results)
227 @type errback: C{method}
228 @param errback: the method to call if an error occurs
229 (optional, defaults to calling the callback with None)
232 def _pongHandler(dict, node=node, self=self, callback=callback, start = datetime.now()):
233 """Node responded properly, callback with response."""
234 n = self.Node(dict['id'], dict['_krpc_sender'][0], dict['_krpc_sender'][1])
235 self.stats.completedAction('join', start)
236 reactor.callLater(0, self.insertNode, n)
238 callback((dict['ip_addr'], dict['port']))
240 def _defaultPong(err, node=node, self=self, callback=callback, errback=errback, start = datetime.now()):
241 """Error occurred, fail node and errback or callback with error."""
242 log.msg("action join failed on %s/%s: %s" % (node.host, node.port, err.getErrorMessage()))
243 self.stats.completedAction('join', start)
244 self.table.nodeFailed(node)
250 self.stats.startedAction('join')
251 df = node.join(self.node.id)
252 df.addCallbacks(_pongHandler, _defaultPong)
254 def findCloseNodes(self, callback=lambda a: None):
255 """Perform a findNode on the ID one away from our own.
257 This will allow us to populate our table with nodes on our network
258 closest to our own. This is called as soon as we start up with an
261 @type callback: C{method}
262 @param callback: the method to call with the results, it must take 1
263 parameter, the list of K closest nodes
264 (optional, defaults to doing nothing with the results)
266 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
267 self.findNode(id, callback)
269 def refreshTable(self, force = False):
270 """Check all the buckets for those that need refreshing.
272 @param force: refresh all buckets regardless of last bucket access time
273 (optional, defaults to False)
278 for bucket in self.table.buckets:
279 if force or (datetime.now() - bucket.lastAccessed >
280 timedelta(seconds=self.config['BUCKET_STALENESS'])):
281 # Choose a random ID in the bucket and try and find it
282 id = newIDInRange(bucket.min, bucket.max)
283 self.findNode(id, callback)
286 """Closes the port and cancels pending later calls."""
287 self.listenport.stopListening()
289 self.next_checkpoint.cancel()
295 """Gather the statistics for the DHT."""
296 return self.stats.formatHTML()
299 def krpc_ping(self, id, _krpc_sender = None):
303 @param id: the node ID of the sender node
304 @type _krpc_sender: (C{string}, C{int})
305 @param _krpc_sender: the sender node's IP address and port
307 if _krpc_sender is not None:
308 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
309 reactor.callLater(0, self.insertNode, n, False)
311 return {"id" : self.node.id}
313 def krpc_join(self, id, _krpc_sender = None):
314 """Add the node by responding with its address and port.
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 reactor.callLater(0, self.insertNode, n, False)
325 _krpc_sender = ('127.0.0.1', self.port)
327 return {"ip_addr" : _krpc_sender[0], "port" : _krpc_sender[1], "id" : self.node.id}
329 def krpc_find_node(self, id, target, _krpc_sender = None):
330 """Find the K closest nodes to the target in the local routing table.
332 @type target: C{string}
333 @param target: the target ID to find nodes for
335 @param id: the node ID of the sender node
336 @type _krpc_sender: (C{string}, C{int})
337 @param _krpc_sender: the sender node's IP address and port
339 if _krpc_sender is not None:
340 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
341 reactor.callLater(0, self.insertNode, n, False)
343 _krpc_sender = ('127.0.0.1', self.port)
345 nodes = self.table.findNodes(target)
346 nodes = map(lambda node: node.contactInfo(), nodes)
347 token = sha(self.token_secrets[0] + _krpc_sender[0]).digest()
348 return {"nodes" : nodes, "token" : token, "id" : self.node.id}
351 class KhashmirRead(KhashmirBase):
352 """The read-only Khashmir class, which can only retrieve (not store) key/value mappings."""
357 def findValue(self, key, callback):
358 """Get the nodes that have values for the key from the global table.
361 @param key: the target key to find the values for
362 @type callback: C{method}
363 @param callback: the method to call with the results, it must take 1
364 parameter, the list of nodes with values
367 nodes = [copy(self.node)]
369 # Search for others starting with the locally found ones
370 state = FindValue(self, key, callback, self.config, self.stats)
371 reactor.callLater(0, state.goWithNodes, nodes)
373 def valueForKey(self, key, callback, searchlocal = True):
374 """Get the values found for key in global table.
376 Callback will be called with a list of values for each peer that
377 returns unique values. The final callback will be an empty list.
380 @param key: the target key to get the values for
381 @type callback: C{method}
382 @param callback: the method to call with the results, it must take 2
383 parameters: the key, and the values found
384 @type searchlocal: C{boolean}
385 @param searchlocal: whether to also look for any local values
388 def _getValueForKey(nodes, key=key, response=callback, self=self, searchlocal=searchlocal):
389 """Use the found nodes to send requests for values to."""
390 # Get any local values
392 l = self.store.retrieveValues(key)
394 node = copy(self.node)
395 node.updateNumValues(len(l))
396 nodes = nodes + [node]
398 state = GetValue(self, key, self.config['RETRIEVE_VALUES'], response, self.config, self.stats)
399 reactor.callLater(0, state.goWithNodes, nodes)
401 # First lookup nodes that have values for the key
402 self.findValue(key, _getValueForKey)
405 def krpc_find_value(self, id, key, _krpc_sender = None):
406 """Find the number of values stored locally for the key, and the K closest nodes.
409 @param key: the target key to find the values and nodes for
411 @param id: the node ID of the sender node
412 @type _krpc_sender: (C{string}, C{int})
413 @param _krpc_sender: the sender node's IP address and port
415 if _krpc_sender is not None:
416 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
417 reactor.callLater(0, self.insertNode, n, False)
419 nodes = self.table.findNodes(key)
420 nodes = map(lambda node: node.contactInfo(), nodes)
421 num_values = self.store.countValues(key)
422 return {'nodes' : nodes, 'num' : num_values, "id": self.node.id}
424 def krpc_get_value(self, id, key, num, _krpc_sender = None):
425 """Retrieve the values stored locally for the key.
428 @param key: the target key to retrieve the values for
430 @param num: the maximum number of values to retrieve, or 0 to
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 reactor.callLater(0, self.insertNode, n, False)
441 l = self.store.retrieveValues(key)
442 if num == 0 or num >= len(l):
443 return {'values' : l, "id": self.node.id}
446 return {'values' : l[:num], "id": self.node.id}
449 class KhashmirWrite(KhashmirRead):
450 """The read-write Khashmir class, which can store and retrieve key/value mappings."""
455 def storeValueForKey(self, key, value, callback=None):
456 """Stores the value for the key in the global table.
458 No status in this implementation, peers respond but don't indicate
459 status of storing values.
462 @param key: the target key to store the value for
463 @type value: C{string}
464 @param value: the value to store with the key
465 @type callback: C{method}
466 @param callback: the method to call with the results, it must take 3
467 parameters: the key, the value stored, and the result of the store
468 (optional, defaults to doing nothing with the results)
470 def _storeValueForKey(nodes, key=key, value=value, response=callback, self=self):
471 """Use the returned K closest nodes to store the key at."""
473 def _storedValueHandler(key, value, sender):
474 """Default callback that does nothing."""
476 response = _storedValueHandler
477 action = StoreValue(self, key, value, self.config['STORE_REDUNDANCY'], response, self.config, self.stats)
478 reactor.callLater(0, action.goWithNodes, nodes)
480 # First find the K closest nodes to operate on.
481 self.findNode(key, _storeValueForKey)
484 def krpc_store_value(self, id, key, value, token, _krpc_sender = None):
485 """Store the value locally with the key.
488 @param key: the target key to store the value for
489 @type value: C{string}
490 @param value: the value to store with the key
491 @param token: the token to confirm that this peer contacted us previously
493 @param id: the node ID of the sender node
494 @type _krpc_sender: (C{string}, C{int})
495 @param _krpc_sender: the sender node's IP address and port
497 if _krpc_sender is not None:
498 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
499 reactor.callLater(0, self.insertNode, n, False)
501 _krpc_sender = ('127.0.0.1', self.port)
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,
520 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
521 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
523 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
524 'KRPC_TIMEOUT': 14, 'KRPC_INITIAL_DELAY': 2,
525 'KEY_EXPIRE': 3600, 'SPEW': False, }
528 d = self.DHT_DEFAULTS.copy()
531 d = self.DHT_DEFAULTS.copy()
538 os.unlink(self.a.store.db)
539 os.unlink(self.b.store.db)
541 def testAddContact(self):
542 self.failUnlessEqual(len(self.a.table.buckets), 1)
543 self.failUnlessEqual(len(self.a.table.buckets[0].l), 0)
545 self.failUnlessEqual(len(self.b.table.buckets), 1)
546 self.failUnlessEqual(len(self.b.table.buckets[0].l), 0)
548 self.a.addContact('127.0.0.1', 4045)
554 self.failUnlessEqual(len(self.a.table.buckets), 1)
555 self.failUnlessEqual(len(self.a.table.buckets[0].l), 1)
556 self.failUnlessEqual(len(self.b.table.buckets), 1)
557 self.failUnlessEqual(len(self.b.table.buckets[0].l), 1)
559 def testStoreRetrieve(self):
560 self.a.addContact('127.0.0.1', 4045)
566 self.a.storeValueForKey(sha('foo').digest(), 'foobar')
573 self.a.valueForKey(sha('foo').digest(), self._cb)
582 def _cb(self, key, val):
584 self.failUnlessEqual(self.got, 1)
585 elif 'foobar' in val:
589 class MultiTest(unittest.TestCase):
593 DHT_DEFAULTS = {'PORT': 9977,
594 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
595 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
597 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
598 'KRPC_TIMEOUT': 14, 'KRPC_INITIAL_DELAY': 2,
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)