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 # Start with our node
178 nodes = [copy(self.node)]
182 d.addCallbacks(callback, errback)
184 d.addCallback(callback)
186 # Start the finding nodes action
187 state = FindNode(self, id, d.callback, self.config, self.stats)
188 reactor.callLater(0, state.goWithNodes, nodes)
190 def insertNode(self, node, contacted = True):
191 """Try to insert a node in our local table, pinging oldest contact if necessary.
193 If all you have is a host/port, then use L{addContact}, which calls this
194 method after receiving the PONG from the remote node. The reason for
195 the seperation is we can't insert a node into the table without its
196 node ID. That means of course the node passed into this method needs
197 to be a properly formed Node object with a valid ID.
199 @type node: L{node.Node}
200 @param node: the new node to try and insert
201 @type contacted: C{boolean}
202 @param contacted: whether the new node is known to be good, i.e.
203 responded to a request (optional, defaults to True)
205 old = self.table.insertNode(node, contacted=contacted)
206 if (old and old.id != self.node.id and
207 (datetime.now() - old.lastSeen) >
208 timedelta(seconds=self.config['MIN_PING_INTERVAL'])):
210 def _staleNodeHandler(err, oldnode = old, newnode = node, self = self):
211 """The pinged node never responded, so replace it."""
212 log.msg("ping failed (%s) %s/%s" % (self.config['PORT'], oldnode.host, oldnode.port))
214 self.table.replaceStaleNode(oldnode, newnode)
216 def _notStaleNodeHandler(dict, old=old, self=self):
217 """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 self.stats.startedAction('ping')
223 df = old.ping(self.node.id)
224 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
226 def sendJoin(self, node, callback=None, errback=None):
227 """Join the DHT by pinging a bootstrap node.
229 @type node: L{node.Node}
230 @param node: the node to send the join to
231 @type callback: C{method}
232 @param callback: the method to call with the results, it must take 1
233 parameter, the contact info returned by the node
234 (optional, defaults to doing nothing with the results)
235 @type errback: C{method}
236 @param errback: the method to call if an error occurs
237 (optional, defaults to calling the callback with None)
240 def _pongHandler(dict, node=node, self=self, callback=callback):
241 """Node responded properly, callback with response."""
242 n = self.Node(dict['id'], dict['_krpc_sender'][0], dict['_krpc_sender'][1])
245 callback((dict['ip_addr'], dict['port']))
247 def _defaultPong(err, node=node, self=self, callback=callback, errback=errback):
248 """Error occurred, fail node and errback or callback with error."""
249 log.msg("join failed (%s) %s/%s" % (self.config['PORT'], node.host, node.port))
251 self.table.nodeFailed(node)
257 self.stats.startedAction('join')
258 df = node.join(self.node.id)
259 df.addCallbacks(_pongHandler, _defaultPong)
261 def findCloseNodes(self, callback=lambda a: None, errback = None):
262 """Perform a findNode on the ID one away from our own.
264 This will allow us to populate our table with nodes on our network
265 closest to our own. This is called as soon as we start up with an
268 @type callback: C{method}
269 @param callback: the method to call with the results, it must take 1
270 parameter, the list of K closest nodes
271 (optional, defaults to doing nothing with the results)
272 @type errback: C{method}
273 @param errback: the method to call if an error occurs
274 (optional, defaults to doing nothing when an error occurs)
276 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
277 self.findNode(id, callback, errback)
279 def refreshTable(self, force = False):
280 """Check all the buckets for those that need refreshing.
282 @param force: refresh all buckets regardless of last bucket access time
283 (optional, defaults to False)
288 for bucket in self.table.buckets:
289 if force or (datetime.now() - bucket.lastAccessed >
290 timedelta(seconds=self.config['BUCKET_STALENESS'])):
291 # Choose a random ID in the bucket and try and find it
292 id = newIDInRange(bucket.min, bucket.max)
293 self.findNode(id, callback)
296 """Closes the port and cancels pending later calls."""
297 self.listenport.stopListening()
299 self.next_checkpoint.cancel()
305 """Gather the statistics for the DHT."""
306 return self.stats.formatHTML()
309 def krpc_ping(self, id, _krpc_sender = None):
313 @param id: the node ID of the sender node
314 @type _krpc_sender: (C{string}, C{int})
315 @param _krpc_sender: the sender node's IP address and port
317 if _krpc_sender is not None:
318 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
319 self.insertNode(n, contacted = False)
321 return {"id" : self.node.id}
323 def krpc_join(self, id, _krpc_sender = None):
324 """Add the node by responding with its address and port.
327 @param id: the node ID of the sender node
328 @type _krpc_sender: (C{string}, C{int})
329 @param _krpc_sender: the sender node's IP address and port
331 if _krpc_sender is not None:
332 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
333 self.insertNode(n, contacted = False)
335 _krpc_sender = ('127.0.0.1', self.port)
337 return {"ip_addr" : _krpc_sender[0], "port" : _krpc_sender[1], "id" : self.node.id}
339 def krpc_find_node(self, id, target, _krpc_sender = None):
340 """Find the K closest nodes to the target in the local routing table.
342 @type target: C{string}
343 @param target: the target ID to find nodes for
345 @param id: the node ID of the sender node
346 @type _krpc_sender: (C{string}, C{int})
347 @param _krpc_sender: the sender node's IP address and port
349 if _krpc_sender is not None:
350 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
351 self.insertNode(n, contacted = False)
353 _krpc_sender = ('127.0.0.1', self.port)
355 nodes = self.table.findNodes(target)
356 nodes = map(lambda node: node.contactInfo(), nodes)
357 token = sha(self.token_secrets[0] + _krpc_sender[0]).digest()
358 return {"nodes" : nodes, "token" : token, "id" : self.node.id}
361 class KhashmirRead(KhashmirBase):
362 """The read-only Khashmir class, which can only retrieve (not store) key/value mappings."""
367 def findValue(self, key, callback, errback=None):
368 """Get the nodes that have values for the key from the global table.
371 @param key: the target key to find the values for
372 @type callback: C{method}
373 @param callback: the method to call with the results, it must take 1
374 parameter, the list of nodes with values
375 @type errback: C{method}
376 @param errback: the method to call if an error occurs
377 (optional, defaults to doing nothing when an error occurs)
380 nodes = [copy(self.node)]
384 d.addCallbacks(callback, errback)
386 d.addCallback(callback)
388 # Search for others starting with the locally found ones
389 state = FindValue(self, key, d.callback, self.config, self.stats)
390 reactor.callLater(0, state.goWithNodes, nodes)
392 def valueForKey(self, key, callback, searchlocal = True):
393 """Get the values found for key in global table.
395 Callback will be called with a list of values for each peer that
396 returns unique values. The final callback will be an empty list.
399 @param key: the target key to get the values for
400 @type callback: C{method}
401 @param callback: the method to call with the results, it must take 2
402 parameters: the key, and the values found
403 @type searchlocal: C{boolean}
404 @param searchlocal: whether to also look for any local values
407 def _getValueForKey(nodes, key=key, response=callback, self=self, searchlocal=searchlocal):
408 """Use the found nodes to send requests for values to."""
409 # Get any local values
411 l = self.store.retrieveValues(key)
413 node = copy(self.node)
414 node.updateNumValues(len(l))
415 nodes = nodes + [node]
417 state = GetValue(self, key, self.config['RETRIEVE_VALUES'], response, self.config, self.stats)
418 reactor.callLater(0, state.goWithNodes, nodes)
420 # First lookup nodes that have values for the key
421 self.findValue(key, _getValueForKey)
424 def krpc_find_value(self, id, key, _krpc_sender = None):
425 """Find the number of values stored locally for the key, and the K closest nodes.
428 @param key: the target key to find the values and nodes for
430 @param id: the node ID of the sender node
431 @type _krpc_sender: (C{string}, C{int})
432 @param _krpc_sender: the sender node's IP address and port
434 if _krpc_sender is not None:
435 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
436 self.insertNode(n, contacted = False)
438 nodes = self.table.findNodes(key)
439 nodes = map(lambda node: node.contactInfo(), nodes)
440 num_values = self.store.countValues(key)
441 return {'nodes' : nodes, 'num' : num_values, "id": self.node.id}
443 def krpc_get_value(self, id, key, num, _krpc_sender = None):
444 """Retrieve the values stored locally for the key.
447 @param key: the target key to retrieve the values for
449 @param num: the maximum number of values to retrieve, or 0 to
452 @param id: the node ID of the sender node
453 @type _krpc_sender: (C{string}, C{int})
454 @param _krpc_sender: the sender node's IP address and port
456 if _krpc_sender is not None:
457 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
458 self.insertNode(n, contacted = False)
460 l = self.store.retrieveValues(key)
461 if num == 0 or num >= len(l):
462 return {'values' : l, "id": self.node.id}
465 return {'values' : l[:num], "id": self.node.id}
468 class KhashmirWrite(KhashmirRead):
469 """The read-write Khashmir class, which can store and retrieve key/value mappings."""
474 def storeValueForKey(self, key, value, callback=None):
475 """Stores the value for the key in the global table.
477 No status in this implementation, peers respond but don't indicate
478 status of storing values.
481 @param key: the target key to store the value for
482 @type value: C{string}
483 @param value: the value to store with the key
484 @type callback: C{method}
485 @param callback: the method to call with the results, it must take 3
486 parameters: the key, the value stored, and the result of the store
487 (optional, defaults to doing nothing with the results)
489 def _storeValueForKey(nodes, key=key, value=value, response=callback, self=self):
490 """Use the returned K closest nodes to store the key at."""
492 def _storedValueHandler(key, value, sender):
493 """Default callback that does nothing."""
495 response = _storedValueHandler
496 action = StoreValue(self, key, value, self.config['STORE_REDUNDANCY'], response, self.config, self.stats)
497 reactor.callLater(0, action.goWithNodes, nodes)
499 # First find the K closest nodes to operate on.
500 self.findNode(key, _storeValueForKey)
503 def krpc_store_value(self, id, key, value, token, _krpc_sender = None):
504 """Store the value locally with the key.
507 @param key: the target key to store the value for
508 @type value: C{string}
509 @param value: the value to store with the key
510 @param token: the token to confirm that this peer contacted us previously
512 @param id: the node ID of the sender node
513 @type _krpc_sender: (C{string}, C{int})
514 @param _krpc_sender: the sender node's IP address and port
516 if _krpc_sender is not None:
517 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
518 self.insertNode(n, contacted = False)
520 _krpc_sender = ('127.0.0.1', self.port)
522 for secret in self.token_secrets:
523 this_token = sha(secret + _krpc_sender[0]).digest()
524 if token == this_token:
525 self.store.storeValue(key, value)
526 return {"id" : self.node.id}
527 raise krpc.KrpcError, (krpc.KRPC_ERROR_INVALID_TOKEN, 'token is invalid, do a find_nodes to get a fresh one')
530 class Khashmir(KhashmirWrite):
531 """The default Khashmir class (currently the read-write L{KhashmirWrite})."""
535 class SimpleTests(unittest.TestCase):
538 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
539 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
540 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
542 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
543 'KEY_EXPIRE': 3600, 'SPEW': False, }
546 d = self.DHT_DEFAULTS.copy()
549 d = self.DHT_DEFAULTS.copy()
556 os.unlink(self.a.store.db)
557 os.unlink(self.b.store.db)
559 def testAddContact(self):
560 self.failUnlessEqual(len(self.a.table.buckets), 1)
561 self.failUnlessEqual(len(self.a.table.buckets[0].l), 0)
563 self.failUnlessEqual(len(self.b.table.buckets), 1)
564 self.failUnlessEqual(len(self.b.table.buckets[0].l), 0)
566 self.a.addContact('127.0.0.1', 4045)
572 self.failUnlessEqual(len(self.a.table.buckets), 1)
573 self.failUnlessEqual(len(self.a.table.buckets[0].l), 1)
574 self.failUnlessEqual(len(self.b.table.buckets), 1)
575 self.failUnlessEqual(len(self.b.table.buckets[0].l), 1)
577 def testStoreRetrieve(self):
578 self.a.addContact('127.0.0.1', 4045)
584 self.a.storeValueForKey(sha('foo').digest(), 'foobar')
591 self.a.valueForKey(sha('foo').digest(), self._cb)
600 def _cb(self, key, val):
602 self.failUnlessEqual(self.got, 1)
603 elif 'foobar' in val:
607 class MultiTest(unittest.TestCase):
611 DHT_DEFAULTS = {'PORT': 9977, 'K': 8, 'HASH_LENGTH': 160,
612 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
613 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
615 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
616 'KEY_EXPIRE': 3600, 'SPEW': False, }
618 def _done(self, val):
623 self.startport = 4088
624 for i in range(self.num):
625 d = self.DHT_DEFAULTS.copy()
626 d['PORT'] = self.startport + i
627 self.l.append(Khashmir(d))
632 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
633 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
634 i.addContact('127.0.0.1', self.l[randrange(0,self.num)].port)
641 i.findCloseNodes(self._done)
646 i.findCloseNodes(self._done)
653 os.unlink(i.store.db)
657 def testStoreRetrieve(self):
664 def _scb(key, value, result):
666 self.l[randrange(0, self.num)].storeValueForKey(K, V, _scb)
674 self.failUnlessEqual(self.got, 1)
680 self.l[randrange(0, self.num)].valueForKey(K, _rcb)