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
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'
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
78 self.cache_dir = FilePath(config.get('DEFAULT', 'CACHE_DIR'))
79 if not self.cache_dir.child(download_dir).exists():
80 self.cache_dir.child(download_dir).makedirs()
81 if not self.cache_dir.child(peer_dir).exists():
82 self.cache_dir.child(peer_dir).makedirs()
83 self.db = DB(self.cache_dir.child('apt-p2p.db'))
85 self.dht.loadConfig(config, config.get('DEFAULT', 'DHT'))
86 self.dht.join().addCallbacks(self.joinComplete, self.joinError)
87 self.stats = StatsLogger(self.db)
88 self.http_server = TopLevel(self.cache_dir.child(download_dir), self.db, self)
89 self.getHTTPFactory = self.http_server.getHTTPFactory
90 self.peers = PeerManager(self.cache_dir.child(peer_dir), self.dht, self.stats)
91 self.mirrors = MirrorManager(self.cache_dir)
92 self.cache = CacheManager(self.cache_dir.child(download_dir), self.db, self)
93 self.my_contact = None
94 reactor.addSystemEventTrigger('before', 'shutdown', self.shutdown)
101 def joinComplete(self, result):
102 """Complete the DHT join process and determine our download information.
104 Called by the DHT when the join has been completed with information
105 on the external IP address and port of this peer.
107 my_addr = findMyIPAddr(result,
108 config.getint(config.get('DEFAULT', 'DHT'), 'PORT'),
109 config.getboolean('DEFAULT', 'LOCAL_OK'))
111 raise RuntimeError, "IP address for this machine could not be found"
112 self.my_contact = compact(my_addr, config.getint('DEFAULT', 'PORT'))
113 self.cache.scanDirectories()
114 reactor.callLater(60, self.refreshFiles)
116 def joinError(self, failure):
117 """Joining the DHT has failed."""
118 log.msg("joining DHT failed miserably")
120 raise RuntimeError, "IP address for this machine could not be found"
122 def refreshFiles(self):
123 """Refresh any files in the DHT that are about to expire."""
124 expireAfter = config.gettime('DEFAULT', 'KEY_REFRESH')
125 hashes = self.db.expiredHashes(expireAfter)
126 if len(hashes.keys()) > 0:
127 log.msg('Refreshing the keys of %d DHT values' % len(hashes.keys()))
128 self._refreshFiles(None, hashes)
130 def _refreshFiles(self, result, hashes):
131 if result is not None:
132 log.msg('Storage resulted in: %r' % result)
135 raw_hash = hashes.keys()[0]
136 self.db.refreshHash(raw_hash)
137 hash = HashObject(raw_hash, pieces = hashes[raw_hash]['pieces'])
139 storeDefer = self.store(hash)
140 storeDefer.addBoth(self._refreshFiles, hashes)
142 reactor.callLater(60, self.refreshFiles)
145 """Retrieve and format the statistics for the program.
148 @return: the formatted HTML page containing the statistics
150 out = '<html><body>\n\n'
151 out += self.stats.formatHTML(self.my_contact)
153 if IDHTStats.implementedBy(self.dhtClass):
154 out += self.dht.getStats()
155 out += '\n</body></html>\n'
159 def check_freshness(self, req, url, modtime, resp):
160 """Send a HEAD to the mirror to check if the response from the cache is still valid.
162 @type req: L{twisted.web2.http.Request}
163 @param req: the initial request sent to the HTTP server by apt
164 @param url: the URI of the actual mirror request
165 @type modtime: C{int}
166 @param modtime: the modified time of the cached file (seconds since epoch)
167 @type resp: L{twisted.web2.http.Response}
168 @param resp: the response from the cache to be sent to apt
169 @rtype: L{twisted.internet.defer.Deferred}
170 @return: a deferred that will be called back with the correct response
172 log.msg('Checking if %s is still fresh' % url)
173 d = self.peers.get('', url, method = "HEAD", modtime = modtime)
174 d.addCallbacks(self.check_freshness_done, self.check_freshness_error,
175 callbackArgs = (req, url, resp), errbackArgs = (req, url))
178 def check_freshness_done(self, resp, req, url, orig_resp):
179 """Process the returned response from the mirror.
181 @type resp: L{twisted.web2.http.Response}
182 @param resp: the response from the mirror to the HEAD request
183 @type req: L{twisted.web2.http.Request}
184 @param req: the initial request sent to the HTTP server by apt
185 @param url: the URI of the actual mirror request
186 @type orig_resp: L{twisted.web2.http.Response}
187 @param orig_resp: the response from the cache to be sent to apt
190 log.msg('Still fresh, returning: %s' % url)
193 log.msg('Stale, need to redownload: %s' % url)
194 return self.get_resp(req, url)
196 def check_freshness_error(self, err, req, url):
197 """Mirror request failed, continue with download.
199 @param err: the response from the mirror to the HEAD request
200 @type req: L{twisted.web2.http.Request}
201 @param req: the initial request sent to the HTTP server by apt
202 @param url: the URI of the actual mirror request
205 return self.get_resp(req, url)
207 def get_resp(self, req, url):
208 """Lookup a hash for the file in the local mirror info.
210 Starts the process of getting a response to an uncached apt request.
212 @type req: L{twisted.web2.http.Request}
213 @param req: the initial request sent to the HTTP server by apt
214 @param url: the URI of the actual mirror request
215 @rtype: L{twisted.internet.defer.Deferred}
216 @return: a deferred that will be called back with the response
220 log.msg('Trying to find hash for %s' % url)
221 findDefer = self.mirrors.findHash(unquote(url))
223 findDefer.addCallbacks(self.findHash_done, self.findHash_error,
224 callbackArgs=(req, url, d), errbackArgs=(req, url, d))
225 findDefer.addErrback(log.err)
228 def findHash_error(self, failure, req, url, d):
229 """Process the error in hash lookup by returning an empty L{HashObject}."""
231 self.findHash_done(HashObject(), req, url, d)
233 def findHash_done(self, hash, req, url, d):
234 """Use the returned hash to lookup the file in the cache.
236 If the hash was not found, the workflow skips down to download from
237 the mirror (L{lookupHash_done}).
239 @type hash: L{Hash.HashObject}
240 @param hash: the hash object containing the expected hash for the file
242 if hash.expected() is None:
243 log.msg('Hash for %s was not found' % url)
244 self.lookupHash_done([], hash, url, d)
246 log.msg('Found hash %s for %s' % (hash.hexexpected(), url))
248 # Lookup hash in cache
249 locations = self.db.lookupHash(hash.expected(), filesOnly = True)
250 self.getCachedFile(hash, req, url, d, locations)
252 def getCachedFile(self, hash, req, url, d, locations):
253 """Try to return the file from the cache, otherwise move on to a DHT lookup.
255 @type locations: C{list} of C{dictionary}
256 @param locations: the files in the cache that match the hash,
257 the dictionary contains a key 'path' whose value is a
258 L{twisted.python.filepath.FilePath} object for the file.
261 log.msg('Failed to return file from cache: %s' % url)
262 self.lookupHash(hash, url, d)
265 # Get the first possible location from the list
266 file = locations.pop(0)['path']
267 log.msg('Returning cached file: %s' % file.path)
270 resp = static.File(file.path).renderHTTP(req)
271 if isinstance(resp, defer.Deferred):
272 resp.addBoth(self._getCachedFile, hash, req, url, d, locations)
274 self._getCachedFile(resp, hash, req, url, d, locations)
276 def _getCachedFile(self, resp, hash, req, url, d, locations):
277 """Check the returned response to be sure it is valid."""
278 if isinstance(resp, failure.Failure):
279 log.msg('Got error trying to get cached file')
281 # Try the next possible location
282 self.getCachedFile(hash, req, url, d, locations)
285 log.msg('Cached response: %r' % resp)
287 if resp.code >= 200 and resp.code < 400:
290 # Try the next possible location
291 self.getCachedFile(hash, req, url, d, locations)
293 def lookupHash(self, hash, url, d):
294 """Lookup the hash in the DHT."""
295 log.msg('Looking up hash in DHT for file: %s' % url)
296 key = hash.expected()
297 lookupDefer = self.dht.getValue(key)
298 lookupDefer.addBoth(self.lookupHash_done, hash, url, d)
300 def lookupHash_done(self, values, hash, url, d):
301 """Start the download of the file.
303 The download will be from peers if the DHT lookup succeeded, or
304 from the mirror otherwise.
306 @type values: C{list} of C{dictionary}
307 @param values: the returned values from the DHT containing peer
310 if not isinstance(values, list) or not values:
311 if not isinstance(values, list):
312 log.msg('DHT lookup for %s failed with error %r' % (url, values))
314 log.msg('Peers for %s were not found' % url)
315 getDefer = self.peers.get(hash, url)
316 getDefer.addCallback(self.cache.save_file, hash, url)
317 getDefer.addErrback(self.cache.save_error, url)
318 getDefer.addCallbacks(d.callback, d.errback)
320 log.msg('Found peers for %s: %r' % (url, values))
321 # Download from the found peers
322 getDefer = self.peers.get(hash, url, values)
323 getDefer.addCallback(self.check_response, hash, url)
324 getDefer.addCallback(self.cache.save_file, hash, url)
325 getDefer.addErrback(self.cache.save_error, url)
326 getDefer.addCallbacks(d.callback, d.errback)
328 def check_response(self, response, hash, url):
329 """Check the response from peers, and download from the mirror if it is not."""
330 if response.code < 200 or response.code >= 300:
331 log.msg('Download from peers failed, going to direct download: %s' % url)
332 getDefer = self.peers.get(hash, url)
336 def new_cached_file(self, file_path, hash, new_hash, url = None, forceDHT = False):
337 """Add a newly cached file to the mirror info and/or the DHT.
339 If the file was downloaded, set url to the path it was downloaded for.
340 Doesn't add a file to the DHT unless a hash was found for it
341 (but does add it anyway if forceDHT is True).
343 @type file_path: L{twisted.python.filepath.FilePath}
344 @param file_path: the location of the file in the local cache
345 @type hash: L{Hash.HashObject}
346 @param hash: the original (expected) hash object containing also the
347 hash of the downloaded file
348 @type new_hash: C{boolean}
349 @param new_hash: whether the has was new to this peer, and so should
352 @param url: the URI of the location of the file in the mirror
353 (optional, defaults to not adding the file to the mirror info)
354 @type forceDHT: C{boolean}
355 @param forceDHT: whether to force addition of the file to the DHT
356 even if the hash was not found in a mirror
357 (optional, defaults to False)
360 self.mirrors.updatedFile(url, file_path)
362 if self.my_contact and hash and new_hash and (hash.expected() is not None or forceDHT):
363 return self.store(hash)
366 def store(self, hash):
367 """Add a key/value pair for the file to the DHT.
369 Sets the key and value from the hash information, and tries to add
373 value = {'c': self.my_contact}
374 pieces = hash.pieceDigests()
376 # Determine how to store any piece data
379 elif len(pieces) <= DHT_PIECES:
380 # Short enough to be stored with our peer contact info
381 value['t'] = {'t': ''.join(pieces)}
382 elif len(pieces) <= TORRENT_PIECES:
383 # Short enough to be stored in a separate key in the DHT
384 value['h'] = sha.new(''.join(pieces)).digest()
386 # Too long, must be served up by our peer HTTP server
387 value['l'] = sha.new(''.join(pieces)).digest()
389 storeDefer = self.dht.storeValue(key, value)
390 storeDefer.addCallbacks(self.store_done, self.store_error,
391 callbackArgs = (hash, ), errbackArgs = (hash.digest(), ))
394 def store_done(self, result, hash):
395 """Add a key/value pair for the pieces of the file to the DHT (if necessary)."""
396 log.msg('Added %s to the DHT: %r' % (hash.hexdigest(), result))
397 pieces = hash.pieceDigests()
398 if len(pieces) > DHT_PIECES and len(pieces) <= TORRENT_PIECES:
399 # Add the piece data key and value to the DHT
400 key = sha.new(''.join(pieces)).digest()
401 value = {'t': ''.join(pieces)}
403 storeDefer = self.dht.storeValue(key, value)
404 storeDefer.addCallbacks(self.store_torrent_done, self.store_error,
405 callbackArgs = (key, ), errbackArgs = (key, ))
409 def store_torrent_done(self, result, key):
410 """Adding the file to the DHT is complete, and so is the workflow."""
411 log.msg('Added torrent string %s to the DHT: %r' % (b2a_hex(key), result))
414 def store_error(self, err, key):
415 """Adding to the DHT failed."""
416 log.msg('An error occurred adding %s to the DHT: %r' % (b2a_hex(key), err))