2 """The main Khashmir program."""
5 warnings.simplefilter("ignore", DeprecationWarning)
7 from datetime import datetime, timedelta
8 from random import randrange, shuffle
13 from twisted.internet.defer import Deferred
14 from twisted.internet import protocol, reactor
15 from twisted.python import log
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)
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):
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
172 # Start with our node
173 nodes = [copy(self.node)]
175 # Start the finding nodes action
176 state = FindNode(self, id, callback, self.config, self.stats)
177 reactor.callLater(0, state.goWithNodes, nodes)
179 def insertNode(self, node, contacted = True):
180 """Try to insert a node in our local table, pinging oldest contact if necessary.
182 If all you have is a host/port, then use L{addContact}, which calls this
183 method after receiving the PONG from the remote node. The reason for
184 the seperation is we can't insert a node into the table without its
185 node ID. That means of course the node passed into this method needs
186 to be a properly formed Node object with a valid ID.
188 @type node: L{node.Node}
189 @param node: the new node to try and insert
190 @type contacted: C{boolean}
191 @param contacted: whether the new node is known to be good, i.e.
192 responded to a request (optional, defaults to True)
194 old = self.table.insertNode(node, contacted=contacted)
195 if (old and old.id != self.node.id and
196 (datetime.now() - old.lastSeen) >
197 timedelta(seconds=self.config['MIN_PING_INTERVAL'])):
199 def _staleNodeHandler(err, oldnode = old, newnode = node, self = self, start = datetime.now()):
200 """The pinged node never responded, so replace it."""
201 log.msg("action ping failed on %s/%s: %s" % (oldnode.host, oldnode.port, err.getErrorMessage()))
202 self.stats.completedAction('ping', start)
203 self.table.replaceStaleNode(oldnode, newnode)
205 def _notStaleNodeHandler(dict, old = old, self = self, start = datetime.now()):
206 """Got a pong from the old node, so update it."""
207 self.stats.completedAction('ping', start)
208 if dict['id'] == old.id:
209 self.table.justSeenNode(old.id)
211 # Bucket is full, check to see if old node is still available
212 self.stats.startedAction('ping')
213 df = old.ping(self.node.id)
214 df.addCallbacks(_notStaleNodeHandler, _staleNodeHandler)
216 def sendJoin(self, node, callback=None, errback=None):
217 """Join the DHT by pinging a bootstrap node.
219 @type node: L{node.Node}
220 @param node: the node to send the join to
221 @type callback: C{method}
222 @param callback: the method to call with the results, it must take 1
223 parameter, the contact info returned by the node
224 (optional, defaults to doing nothing with the results)
225 @type errback: C{method}
226 @param errback: the method to call if an error occurs
227 (optional, defaults to calling the callback with None)
230 def _pongHandler(dict, node=node, self=self, callback=callback, start = datetime.now()):
231 """Node responded properly, callback with response."""
232 n = self.Node(dict['id'], dict['_krpc_sender'][0], dict['_krpc_sender'][1])
233 self.stats.completedAction('join', start)
234 reactor.callLater(0, self.insertNode, n)
236 callback((dict['ip_addr'], dict['port']))
238 def _defaultPong(err, node=node, self=self, callback=callback, errback=errback, start = datetime.now()):
239 """Error occurred, fail node and errback or callback with error."""
240 log.msg("action join failed on %s/%s: %s" % (node.host, node.port, err.getErrorMessage()))
241 self.stats.completedAction('join', start)
242 self.table.nodeFailed(node)
248 self.stats.startedAction('join')
249 df = node.join(self.node.id)
250 df.addCallbacks(_pongHandler, _defaultPong)
252 def findCloseNodes(self, callback=lambda a: None):
253 """Perform a findNode on the ID one away from our own.
255 This will allow us to populate our table with nodes on our network
256 closest to our own. This is called as soon as we start up with an
259 @type callback: C{method}
260 @param callback: the method to call with the results, it must take 1
261 parameter, the list of K closest nodes
262 (optional, defaults to doing nothing with the results)
264 id = self.node.id[:-1] + chr((ord(self.node.id[-1]) + 1) % 256)
265 self.findNode(id, callback)
267 def refreshTable(self, force = False):
268 """Check all the buckets for those that need refreshing.
270 @param force: refresh all buckets regardless of last bucket access time
271 (optional, defaults to False)
276 for bucket in self.table.buckets:
277 if force or (datetime.now() - bucket.lastAccessed >
278 timedelta(seconds=self.config['BUCKET_STALENESS'])):
279 # Choose a random ID in the bucket and try and find it
280 id = newIDInRange(bucket.min, bucket.max)
281 self.findNode(id, callback)
284 """Closes the port and cancels pending later calls."""
285 self.listenport.stopListening()
287 self.next_checkpoint.cancel()
293 """Gather the statistics for the DHT."""
294 return self.stats.formatHTML()
297 def krpc_ping(self, id, _krpc_sender = None):
301 @param id: the node ID of the sender node
302 @type _krpc_sender: (C{string}, C{int})
303 @param _krpc_sender: the sender node's IP address and port
305 if _krpc_sender is not None:
306 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
307 reactor.callLater(0, self.insertNode, n, False)
309 return {"id" : self.node.id}
311 def krpc_join(self, id, _krpc_sender = None):
312 """Add the node by responding with its address and port.
315 @param id: the node ID of the sender node
316 @type _krpc_sender: (C{string}, C{int})
317 @param _krpc_sender: the sender node's IP address and port
319 if _krpc_sender is not None:
320 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
321 reactor.callLater(0, self.insertNode, n, False)
323 _krpc_sender = ('127.0.0.1', self.port)
325 return {"ip_addr" : _krpc_sender[0], "port" : _krpc_sender[1], "id" : self.node.id}
327 def krpc_find_node(self, id, target, _krpc_sender = None):
328 """Find the K closest nodes to the target in the local routing table.
330 @type target: C{string}
331 @param target: the target ID to find nodes for
333 @param id: the node ID of the sender node
334 @type _krpc_sender: (C{string}, C{int})
335 @param _krpc_sender: the sender node's IP address and port
337 if _krpc_sender is not None:
338 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
339 reactor.callLater(0, self.insertNode, n, False)
341 _krpc_sender = ('127.0.0.1', self.port)
343 nodes = self.table.findNodes(target)
344 nodes = map(lambda node: node.contactInfo(), nodes)
345 token = sha(self.token_secrets[0] + _krpc_sender[0]).digest()
346 return {"nodes" : nodes, "token" : token, "id" : self.node.id}
349 class KhashmirRead(KhashmirBase):
350 """The read-only Khashmir class, which can only retrieve (not store) key/value mappings."""
355 def findValue(self, key, callback):
356 """Get the nodes that have values for the key from the global table.
359 @param key: the target key to find the values for
360 @type callback: C{method}
361 @param callback: the method to call with the results, it must take 1
362 parameter, the list of nodes with values
365 nodes = [copy(self.node)]
367 # Search for others starting with the locally found ones
368 state = FindValue(self, key, callback, self.config, self.stats)
369 reactor.callLater(0, state.goWithNodes, nodes)
371 def valueForKey(self, key, callback, searchlocal = True):
372 """Get the values found for key in global table.
374 Callback will be called with a list of values for each peer that
375 returns unique values. The final callback will be an empty list.
378 @param key: the target key to get the values for
379 @type callback: C{method}
380 @param callback: the method to call with the results, it must take 2
381 parameters: the key, and the values found
382 @type searchlocal: C{boolean}
383 @param searchlocal: whether to also look for any local values
386 def _getValueForKey(nodes, key=key, response=callback, self=self, searchlocal=searchlocal):
387 """Use the found nodes to send requests for values to."""
388 # Get any local values
390 l = self.store.retrieveValues(key)
392 node = copy(self.node)
393 node.updateNumValues(len(l))
394 nodes = nodes + [node]
396 state = GetValue(self, key, self.config['RETRIEVE_VALUES'], response, self.config, self.stats)
397 reactor.callLater(0, state.goWithNodes, nodes)
399 # First lookup nodes that have values for the key
400 self.findValue(key, _getValueForKey)
403 def krpc_find_value(self, id, key, _krpc_sender = None):
404 """Find the number of values stored locally for the key, and the K closest nodes.
407 @param key: the target key to find the values and nodes for
409 @param id: the node ID of the sender node
410 @type _krpc_sender: (C{string}, C{int})
411 @param _krpc_sender: the sender node's IP address and port
413 if _krpc_sender is not None:
414 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
415 reactor.callLater(0, self.insertNode, n, False)
417 nodes = self.table.findNodes(key)
418 nodes = map(lambda node: node.contactInfo(), nodes)
419 num_values = self.store.countValues(key)
420 return {'nodes' : nodes, 'num' : num_values, "id": self.node.id}
422 def krpc_get_value(self, id, key, num, _krpc_sender = None):
423 """Retrieve the values stored locally for the key.
426 @param key: the target key to retrieve the values for
428 @param num: the maximum number of values to retrieve, or 0 to
431 @param id: the node ID of the sender node
432 @type _krpc_sender: (C{string}, C{int})
433 @param _krpc_sender: the sender node's IP address and port
435 if _krpc_sender is not None:
436 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
437 reactor.callLater(0, self.insertNode, n, False)
439 l = self.store.retrieveValues(key)
440 if num == 0 or num >= len(l):
441 return {'values' : l, "id": self.node.id}
444 return {'values' : l[:num], "id": self.node.id}
447 class KhashmirWrite(KhashmirRead):
448 """The read-write Khashmir class, which can store and retrieve key/value mappings."""
453 def storeValueForKey(self, key, value, callback=None):
454 """Stores the value for the key in the global table.
456 No status in this implementation, peers respond but don't indicate
457 status of storing values.
460 @param key: the target key to store the value for
461 @type value: C{string}
462 @param value: the value to store with the key
463 @type callback: C{method}
464 @param callback: the method to call with the results, it must take 3
465 parameters: the key, the value stored, and the result of the store
466 (optional, defaults to doing nothing with the results)
468 def _storeValueForKey(nodes, key=key, value=value, response=callback, self=self):
469 """Use the returned K closest nodes to store the key at."""
471 def _storedValueHandler(key, value, sender):
472 """Default callback that does nothing."""
474 response = _storedValueHandler
475 action = StoreValue(self, key, value, self.config['STORE_REDUNDANCY'], response, self.config, self.stats)
476 reactor.callLater(0, action.goWithNodes, nodes)
478 # First find the K closest nodes to operate on.
479 self.findNode(key, _storeValueForKey)
482 def krpc_store_value(self, id, key, value, token, _krpc_sender = None):
483 """Store the value locally with the key.
486 @param key: the target key to store the value for
487 @type value: C{string}
488 @param value: the value to store with the key
489 @param token: the token to confirm that this peer contacted us previously
491 @param id: the node ID of the sender node
492 @type _krpc_sender: (C{string}, C{int})
493 @param _krpc_sender: the sender node's IP address and port
495 if _krpc_sender is not None:
496 n = self.Node(id, _krpc_sender[0], _krpc_sender[1])
497 reactor.callLater(0, self.insertNode, n, False)
499 _krpc_sender = ('127.0.0.1', self.port)
501 for secret in self.token_secrets:
502 this_token = sha(secret + _krpc_sender[0]).digest()
503 if token == this_token:
504 self.store.storeValue(key, value)
505 return {"id" : self.node.id}
506 raise krpc.KrpcError, (krpc.KRPC_ERROR_INVALID_TOKEN, 'token is invalid, do a find_nodes to get a fresh one')
509 class Khashmir(KhashmirWrite):
510 """The default Khashmir class (currently the read-write L{KhashmirWrite})."""
514 class SimpleTests(unittest.TestCase):
517 DHT_DEFAULTS = {'PORT': 9977,
518 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
519 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
521 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
522 'KRPC_TIMEOUT': 14, 'KRPC_INITIAL_DELAY': 2,
523 'KEY_EXPIRE': 3600, 'SPEW': False, }
526 d = self.DHT_DEFAULTS.copy()
529 d = self.DHT_DEFAULTS.copy()
536 os.unlink(self.a.store.db)
537 os.unlink(self.b.store.db)
539 def testAddContact(self):
540 self.failUnlessEqual(len(self.a.table.buckets), 1)
541 self.failUnlessEqual(len(self.a.table.buckets[0].l), 0)
543 self.failUnlessEqual(len(self.b.table.buckets), 1)
544 self.failUnlessEqual(len(self.b.table.buckets[0].l), 0)
546 self.a.addContact('127.0.0.1', 4045)
552 self.failUnlessEqual(len(self.a.table.buckets), 1)
553 self.failUnlessEqual(len(self.a.table.buckets[0].l), 1)
554 self.failUnlessEqual(len(self.b.table.buckets), 1)
555 self.failUnlessEqual(len(self.b.table.buckets[0].l), 1)
557 def testStoreRetrieve(self):
558 self.a.addContact('127.0.0.1', 4045)
564 self.a.storeValueForKey(sha('foo').digest(), 'foobar')
571 self.a.valueForKey(sha('foo').digest(), self._cb)
580 def _cb(self, key, val):
582 self.failUnlessEqual(self.got, 1)
583 elif 'foobar' in val:
587 class MultiTest(unittest.TestCase):
591 DHT_DEFAULTS = {'PORT': 9977,
592 'CHECKPOINT_INTERVAL': 300, 'CONCURRENT_REQS': 4,
593 'STORE_REDUNDANCY': 3, 'RETRIEVE_VALUES': -10000,
595 'MIN_PING_INTERVAL': 900,'BUCKET_STALENESS': 3600,
596 'KRPC_TIMEOUT': 14, 'KRPC_INITIAL_DELAY': 2,
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)