import logging from twisted.internet import defer from zope.interface import implements from lbrynet import interfaces from lbrynet import conf from lbrynet.core.client.ClientProtocol import ClientProtocolFactory from lbrynet.core.Error import InsufficientFundsError log = logging.getLogger(__name__) class PeerConnectionHandler(object): def __init__(self, request_creators, factory): self.request_creators = request_creators self.factory = factory self.connection = None class ConnectionManager(object): implements(interfaces.IConnectionManager) def __init__(self, downloader, rate_limiter, primary_request_creators, secondary_request_creators): self.downloader = downloader self.rate_limiter = rate_limiter self._primary_request_creators = primary_request_creators self._secondary_request_creators = secondary_request_creators self._peer_connections = {} # {Peer: PeerConnectionHandler} self._connections_closing = {} # {Peer: deferred (fired when the connection is closed)} self._next_manage_call = None # a deferred that gets fired when a _manage call is set self._manage_deferred = None self.stopped = True def start(self): from twisted.internet import reactor self.stopped = False if self._next_manage_call is not None and self._next_manage_call.active() is True: self._next_manage_call.cancel() self._next_manage_call = reactor.callLater(0, self._manage) return defer.succeed(True) @defer.inlineCallbacks def stop(self): self.stopped = True # wait for the current manage call to finish if self._manage_deferred: yield self._manage_deferred # in case we stopped between manage calls, cancel the next one if self._next_manage_call and self._next_manage_call.active(): self._next_manage_call.cancel() self._next_manage_call = None yield self._close_peers() def _close_peers(self): def disconnect_peer(p): d = defer.Deferred() self._connections_closing[p] = d self._peer_connections[p].connection.disconnect() if p in self._peer_connections: del self._peer_connections[p] return d def close_connection(p): log.info("Abruptly closing a connection to %s due to downloading being paused", p) if self._peer_connections[p].factory.p is not None: d = self._peer_connections[p].factory.p.cancel_requests() else: d = defer.succeed(True) d.addBoth(lambda _: disconnect_peer(p)) return d closing_deferreds = [close_connection(peer) for peer in self._peer_connections.keys()] return defer.DeferredList(closing_deferreds) @defer.inlineCallbacks def get_next_request(self, peer, protocol): log.debug("Trying to get the next request for peer %s", peer) if not peer in self._peer_connections or self.stopped is True: log.debug("The peer has already been told to shut down.") defer.returnValue(False) requests = yield self._send_primary_requests(peer, protocol) have_request = any(r[1] for r in requests if r[0] is True) if have_request: yield self._send_secondary_requests(peer, protocol) defer.returnValue(have_request) def _send_primary_requests(self, peer, protocol): def handle_error(err): err.trap(InsufficientFundsError) self.downloader.insufficient_funds(err) return False def check_if_request_sent(request_sent, request_creator): if peer not in self._peer_connections: # This can happen if the connection is told to close return False if request_sent is False: if request_creator in self._peer_connections[peer].request_creators: self._peer_connections[peer].request_creators.remove(request_creator) else: if not request_creator in self._peer_connections[peer].request_creators: self._peer_connections[peer].request_creators.append(request_creator) return request_sent ds = [] for p_r_c in self._primary_request_creators: d = p_r_c.send_next_request(peer, protocol) d.addErrback(handle_error) d.addCallback(check_if_request_sent, p_r_c) ds.append(d) return defer.DeferredList(ds, fireOnOneErrback=True) def _send_secondary_requests(self, peer, protocol): ds = [ s_r_c.send_next_request(peer, protocol) for s_r_c in self._secondary_request_creators ] return defer.DeferredList(ds) def protocol_disconnected(self, peer, protocol): if peer in self._peer_connections: del self._peer_connections[peer] if peer in self._connections_closing: d = self._connections_closing[peer] del self._connections_closing[peer] d.callback(True) @defer.inlineCallbacks def _manage(self): self._manage_deferred = defer.Deferred() from twisted.internet import reactor if len(self._peer_connections) < conf.settings.max_connections_per_stream: try: ordered_request_creators = self._rank_request_creator_connections() peers = yield self._get_new_peers(ordered_request_creators) peer = self._pick_best_peer(peers) yield self._connect_to_peer(peer) except Exception: # log this otherwise it will just end up as an unhandled error in deferred log.exception('Something bad happened picking a peer') self._manage_deferred.callback(None) self._manage_deferred = None if not self.stopped: self._next_manage_call = reactor.callLater(1, self._manage) def _rank_request_creator_connections(self): """Returns an ordered list of our request creators, ranked according to which has the least number of connections open that it likes """ def count_peers(request_creator): return len([ p for p in self._peer_connections.itervalues() if request_creator in p.request_creators]) return sorted(self._primary_request_creators, key=count_peers) @defer.inlineCallbacks def _get_new_peers(self, request_creators): log.debug("Trying to get a new peer to connect to") if not request_creators: defer.returnValue(None) log.debug("Got a creator to check: %s", request_creators[0]) new_peers = yield request_creators[0].get_new_peers() if not new_peers: new_peers = yield self._get_new_peers(request_creators[1:]) defer.returnValue(new_peers) def _pick_best_peer(self, peers): # TODO: Eventually rank them based on past performance/reputation. For now # TODO: just pick the first to which we don't have an open connection log.debug("Got a list of peers to choose from: %s", peers) if peers is None: return None for peer in peers: if not peer in self._peer_connections: log.debug("Got a good peer. Returning peer %s", peer) return peer log.debug("Couldn't find a good peer to connect to") return None def _connect_to_peer(self, peer): if peer is None or self.stopped: return from twisted.internet import reactor log.debug("Trying to connect to %s", peer) factory = ClientProtocolFactory(peer, self.rate_limiter, self) self._peer_connections[peer] = PeerConnectionHandler(self._primary_request_creators[:], factory) connection = reactor.connectTCP(peer.host, peer.port, factory) self._peer_connections[peer].connection = connection