2 """The main program code.
4 @var DHT_PIECES: the maximum number of pieces to store with our contact info
6 @var TORRENT_PIECES: the maximum number of pieces to store as a separate entry
8 @var download_dir: the name of the directory to use for downloaded files
9 @var peer_dir: the name of the directory to use for peer downloads
12 from binascii import b2a_hex
13 from urlparse import urlunparse
14 from urllib import unquote
17 from twisted.internet import defer, reactor, protocol
18 from twisted.web2 import server, http, http_headers, static
19 from twisted.python import log, failure
20 from twisted.python.filepath import FilePath
22 from interfaces import IDHT, IDHTStats
23 from apt_p2p_conf import config
24 from PeerManager import PeerManager
25 from HTTPServer import TopLevel
26 from MirrorManager import MirrorManager
27 from CacheManager import CacheManager
28 from Hash import HashObject
30 from stats import StatsLogger
31 from util import findMyIPAddr, compact
36 download_dir = 'cache'
39 class AptP2P(protocol.Factory):
40 """The main code object that does all of the work.
42 Contains all of the sub-components that do all the low-level work, and
43 coordinates communication between them.
45 @type dhtClass: L{interfaces.IDHT}
46 @ivar dhtClass: the DHT class to use
47 @type cache_dir: L{twisted.python.filepath.FilePath}
48 @ivar cache_dir: the directory to use for storing all files
50 @ivar db: the database to use for tracking files and hashes
51 @type dht: L{interfaces.IDHT}
52 @ivar dht: the DHT instance
53 @type stats: L{stats.StatsLogger}
54 @ivar stats: the statistics logger to record sent data to
55 @type http_server: L{HTTPServer.TopLevel}
56 @ivar http_server: the web server that will handle all requests from apt
58 @type peers: L{PeerManager.PeerManager}
59 @ivar peers: the manager of all downloads from mirrors and other peers
60 @type mirrors: L{MirrorManager.MirrorManager}
61 @ivar mirrors: the manager of downloaded information about mirrors which
62 can be queried to get hashes from file names
63 @type cache: L{CacheManager.CacheManager}
64 @ivar cache: the manager of all downloaded files
65 @type my_contact: C{string}
66 @ivar my_contact: the 6-byte compact peer representation of this peer's
67 download information (IP address and port)
70 def __init__(self, dhtClass):
71 """Initialize all the sub-components.
73 @type dhtClass: L{interfaces.IDHT}
74 @param dhtClass: the DHT class to use
76 log.msg('Initializing the main apt_p2p application')
77 self.dhtClass = dhtClass
80 def startFactory(self):
81 reactor.callLater(0, self._startFactory)
83 def _startFactory(self):
84 log.msg('Starting the main apt_p2p application')
85 self.cache_dir = FilePath(config.get('DEFAULT', 'CACHE_DIR'))
86 if not self.cache_dir.child(download_dir).exists():
87 self.cache_dir.child(download_dir).makedirs()
88 if not self.cache_dir.child(peer_dir).exists():
89 self.cache_dir.child(peer_dir).makedirs()
90 self.db = DB(self.cache_dir.child('apt-p2p.db'))
91 self.dht = self.dhtClass()
92 self.dht.loadConfig(config, config.get('DEFAULT', 'DHT'))
93 self.dht.join().addCallbacks(self.joinComplete, self.joinError)
94 self.stats = StatsLogger(self.db)
95 self.http_server = TopLevel(self.cache_dir.child(download_dir), self.db, self)
96 self.http_server.getHTTPFactory().startFactory()
97 self.peers = PeerManager(self.cache_dir.child(peer_dir), self.dht, self.stats)
98 self.mirrors = MirrorManager(self.cache_dir)
99 self.cache = CacheManager(self.cache_dir.child(download_dir), self.db, self)
100 self.my_contact = None
102 def stopFactory(self):
103 log.msg('Stoppping the main apt_p2p application')
104 self.http_server.getHTTPFactory().stopFactory()
105 self.mirrors.cleanup()
109 def buildProtocol(self, addr):
110 return self.http_server.getHTTPFactory().buildProtocol(addr)
113 def joinComplete(self, result):
114 """Complete the DHT join process and determine our download information.
116 Called by the DHT when the join has been completed with information
117 on the external IP address and port of this peer.
119 my_addr = findMyIPAddr(result,
120 config.getint(config.get('DEFAULT', 'DHT'), 'PORT'),
121 config.getboolean('DEFAULT', 'LOCAL_OK'))
123 raise RuntimeError, "IP address for this machine could not be found"
124 self.my_contact = compact(my_addr, config.getint('DEFAULT', 'PORT'))
125 self.cache.scanDirectories()
126 reactor.callLater(60, self.refreshFiles)
128 def joinError(self, failure):
129 """Joining the DHT has failed."""
130 log.msg("joining DHT failed miserably")
132 raise RuntimeError, "IP address for this machine could not be found"
134 def refreshFiles(self):
135 """Refresh any files in the DHT that are about to expire."""
136 expireAfter = config.gettime('DEFAULT', 'KEY_REFRESH')
137 hashes = self.db.expiredHashes(expireAfter)
138 if len(hashes.keys()) > 0:
139 log.msg('Refreshing the keys of %d DHT values' % len(hashes.keys()))
140 self._refreshFiles(None, hashes)
142 def _refreshFiles(self, result, hashes):
143 if result is not None:
144 log.msg('Storage resulted in: %r' % result)
147 raw_hash = hashes.keys()[0]
148 self.db.refreshHash(raw_hash)
149 hash = HashObject(raw_hash, pieces = hashes[raw_hash]['pieces'])
151 storeDefer = self.store(hash)
152 storeDefer.addBoth(self._refreshFiles, hashes)
154 reactor.callLater(60, self.refreshFiles)
157 """Retrieve and format the statistics for the program.
160 @return: the formatted HTML page containing the statistics
162 out = '<html><body>\n\n'
163 out += self.stats.formatHTML(self.my_contact)
165 if IDHTStats.implementedBy(self.dhtClass):
166 out += self.dht.getStats()
167 out += '\n</body></html>\n'
171 def get_resp(self, req, url, orig_resp = None):
172 """Lookup a hash for the file in the local mirror info.
174 Starts the process of getting a response to an apt request.
176 @type req: L{twisted.web2.http.Request}
177 @param req: the initial request sent to the HTTP server by apt
178 @param url: the URI of the actual mirror request
179 @type orig_resp: L{twisted.web2.http.Response}
180 @param orig_resp: the response from the cache to be sent to apt
181 (optional, ignored if missing)
182 @rtype: L{twisted.internet.defer.Deferred}
183 @return: a deferred that will be called back with the response
187 log.msg('Trying to find hash for %s' % url)
188 findDefer = self.mirrors.findHash(unquote(url))
190 findDefer.addCallbacks(self.findHash_done, self.findHash_error,
191 callbackArgs=(req, url, orig_resp, d),
192 errbackArgs=(req, url, orig_resp, d))
195 def findHash_error(self, failure, req, url, orig_resp, d):
196 """Process the error in hash lookup by returning an empty L{HashObject}."""
197 log.msg('Hash lookup for %s resulted in an error: %s' %
198 (url, failure.getErrorMessage()))
199 self.findHash_done(HashObject(), req, url, orig_resp, d)
201 def findHash_done(self, hash, req, url, orig_resp, d):
202 """Use the returned hash to lookup the file in the cache.
204 If the hash was not found, the workflow skips down to download from
205 the mirror (L{startDownload}), or checks the freshness of an old
206 response if there is one.
208 @type hash: L{Hash.HashObject}
209 @param hash: the hash object containing the expected hash for the file
211 if hash.expected() is None:
212 log.msg('Hash for %s was not found' % url)
213 # Send the old response or get a new one
215 self.check_freshness(req, url, orig_resp, d)
217 self.startDownload([], req, hash, url, d)
219 log.msg('Found hash %s for %s' % (hash.hexexpected(), url))
221 # Lookup hash in cache
222 locations = self.db.lookupHash(hash.expected(), filesOnly = True)
223 self.getCachedFile(hash, req, url, d, locations)
225 def check_freshness(self, req, url, orig_resp, d):
226 """Send a HEAD to the mirror to check if the response from the cache is still valid.
228 @type req: L{twisted.web2.http.Request}
229 @param req: the initial request sent to the HTTP server by apt
230 @param url: the URI of the actual mirror request
231 @type orig_resp: L{twisted.web2.http.Response}
232 @param orig_resp: the response from the cache to be sent to apt
233 @rtype: L{twisted.internet.defer.Deferred}
234 @return: a deferred that will be called back with the correct response
236 log.msg('Checking if %s is still fresh' % url)
237 modtime = orig_resp.headers.getHeader('Last-Modified')
238 headDefer = self.peers.get(HashObject(), url, method = "HEAD",
240 headDefer.addCallbacks(self.check_freshness_done,
241 self.check_freshness_error,
242 callbackArgs = (req, url, orig_resp, d),
243 errbackArgs = (req, url, d))
245 def check_freshness_done(self, resp, req, url, orig_resp, d):
246 """Return the fresh response, if stale start to redownload.
248 @type resp: L{twisted.web2.http.Response}
249 @param resp: the response from the mirror to the HEAD request
250 @type req: L{twisted.web2.http.Request}
251 @param req: the initial request sent to the HTTP server by apt
252 @param url: the URI of the actual mirror request
253 @type orig_resp: L{twisted.web2.http.Response}
254 @param orig_resp: the response from the cache to be sent to apt
257 log.msg('Still fresh, returning: %s' % url)
258 d.callback(orig_resp)
260 log.msg('Stale, need to redownload: %s' % url)
261 self.startDownload([], req, HashObject(), url, d)
263 def check_freshness_error(self, err, req, url, d):
264 """Mirror request failed, continue with download.
266 @param err: the response from the mirror to the HEAD request
267 @type req: L{twisted.web2.http.Request}
268 @param req: the initial request sent to the HTTP server by apt
269 @param url: the URI of the actual mirror request
272 self.startDownload([], req, HashObject(), url, d)
274 def getCachedFile(self, hash, req, url, d, locations):
275 """Try to return the file from the cache, otherwise move on to a DHT lookup.
277 @type locations: C{list} of C{dictionary}
278 @param locations: the files in the cache that match the hash,
279 the dictionary contains a key 'path' whose value is a
280 L{twisted.python.filepath.FilePath} object for the file.
283 log.msg('Failed to return file from cache: %s' % url)
284 self.lookupHash(req, hash, url, d)
287 # Get the first possible location from the list
288 file = locations.pop(0)['path']
289 log.msg('Returning cached file: %s' % file.path)
292 resp = static.File(file.path).renderHTTP(req)
293 if isinstance(resp, defer.Deferred):
294 resp.addBoth(self._getCachedFile, hash, req, url, d, locations)
296 self._getCachedFile(resp, hash, req, url, d, locations)
298 def _getCachedFile(self, resp, hash, req, url, d, locations):
299 """Check the returned response to be sure it is valid."""
300 if isinstance(resp, failure.Failure):
301 log.msg('Got error trying to get cached file')
303 # Try the next possible location
304 self.getCachedFile(hash, req, url, d, locations)
307 log.msg('Cached response: %r' % resp)
309 if resp.code >= 200 and resp.code < 400:
312 # Try the next possible location
313 self.getCachedFile(hash, req, url, d, locations)
315 def lookupHash(self, req, hash, url, d):
316 """Lookup the hash in the DHT."""
317 log.msg('Looking up hash in DHT for file: %s' % url)
318 key = hash.expected()
319 lookupDefer = self.dht.getValue(key)
320 lookupDefer.addBoth(self.startDownload, req, hash, url, d)
322 def startDownload(self, values, req, hash, url, d):
323 """Start the download of the file.
325 The download will be from peers if the DHT lookup succeeded, or
326 from the mirror otherwise.
328 @type values: C{list} of C{dictionary}
329 @param values: the returned values from the DHT containing peer
332 # Remove some headers Apt sets in the request
333 req.headers.removeHeader('If-Modified-Since')
334 req.headers.removeHeader('Range')
335 req.headers.removeHeader('If-Range')
337 if not isinstance(values, list) or not values:
338 if not isinstance(values, list):
339 log.msg('DHT lookup for %s failed with error %r' % (url, values))
341 log.msg('Peers for %s were not found' % url)
342 getDefer = self.peers.get(hash, url)
343 getDefer.addCallback(self.cache.save_file, hash, url)
344 getDefer.addErrback(self.cache.save_error, url)
345 getDefer.addCallbacks(d.callback, d.errback)
347 log.msg('Found peers for %s: %r' % (url, values))
348 # Download from the found peers
349 getDefer = self.peers.get(hash, url, values)
350 getDefer.addCallback(self.check_response, hash, url)
351 getDefer.addCallback(self.cache.save_file, hash, url)
352 getDefer.addErrback(self.cache.save_error, url)
353 getDefer.addCallbacks(d.callback, d.errback)
355 def check_response(self, response, hash, url):
356 """Check the response from peers, and download from the mirror if it is not."""
357 if response.code < 200 or response.code >= 300:
358 log.msg('Download from peers failed, going to direct download: %s' % url)
359 getDefer = self.peers.get(hash, url)
363 def new_cached_file(self, file_path, hash, new_hash, url = None, forceDHT = False):
364 """Add a newly cached file to the mirror info and/or the DHT.
366 If the file was downloaded, set url to the path it was downloaded for.
367 Doesn't add a file to the DHT unless a hash was found for it
368 (but does add it anyway if forceDHT is True).
370 @type file_path: L{twisted.python.filepath.FilePath}
371 @param file_path: the location of the file in the local cache
372 @type hash: L{Hash.HashObject}
373 @param hash: the original (expected) hash object containing also the
374 hash of the downloaded file
375 @type new_hash: C{boolean}
376 @param new_hash: whether the has was new to this peer, and so should
379 @param url: the URI of the location of the file in the mirror
380 (optional, defaults to not adding the file to the mirror info)
381 @type forceDHT: C{boolean}
382 @param forceDHT: whether to force addition of the file to the DHT
383 even if the hash was not found in a mirror
384 (optional, defaults to False)
387 self.mirrors.updatedFile(url, file_path)
389 if self.my_contact and hash and new_hash and (hash.expected() is not None or forceDHT):
390 return self.store(hash)
393 def store(self, hash):
394 """Add a key/value pair for the file to the DHT.
396 Sets the key and value from the hash information, and tries to add
400 value = {'c': self.my_contact}
401 pieces = hash.pieceDigests()
403 # Determine how to store any piece data
406 elif len(pieces) <= DHT_PIECES:
407 # Short enough to be stored with our peer contact info
408 value['t'] = {'t': ''.join(pieces)}
409 elif len(pieces) <= TORRENT_PIECES:
410 # Short enough to be stored in a separate key in the DHT
411 value['h'] = sha.new(''.join(pieces)).digest()
413 # Too long, must be served up by our peer HTTP server
414 value['l'] = sha.new(''.join(pieces)).digest()
416 storeDefer = self.dht.storeValue(key, value)
417 storeDefer.addCallbacks(self.store_done, self.store_error,
418 callbackArgs = (hash, ), errbackArgs = (hash.digest(), ))
421 def store_done(self, result, hash):
422 """Add a key/value pair for the pieces of the file to the DHT (if necessary)."""
423 log.msg('Added %s to the DHT: %r' % (hash.hexdigest(), result))
424 pieces = hash.pieceDigests()
425 if len(pieces) > DHT_PIECES and len(pieces) <= TORRENT_PIECES:
426 # Add the piece data key and value to the DHT
427 key = sha.new(''.join(pieces)).digest()
428 value = {'t': ''.join(pieces)}
430 storeDefer = self.dht.storeValue(key, value)
431 storeDefer.addCallbacks(self.store_torrent_done, self.store_error,
432 callbackArgs = (key, ), errbackArgs = (key, ))
436 def store_torrent_done(self, result, key):
437 """Adding the file to the DHT is complete, and so is the workflow."""
438 log.msg('Added torrent string %s to the DHT: %r' % (b2a_hex(key), result))
441 def store_error(self, err, key):
442 """Adding to the DHT failed."""
443 log.msg('An error occurred adding %s to the DHT: %r' % (b2a_hex(key), err))