import os import asyncio import logging import treq import json import math import binascii from hashlib import sha256 from types import SimpleNamespace from twisted.internet import defer, threads, reactor, error, task from aioupnp import __version__ as aioupnp_version from aioupnp.upnp import UPnP from aioupnp.fault import UPnPError import lbrynet.schema from lbrynet import conf from lbrynet.blob.EncryptedFileManager import EncryptedFileManager from lbrynet.blob.client.EncryptedFileDownloader import EncryptedFileSaverFactory from lbrynet.blob.client.EncryptedFileOptions import add_lbry_file_to_sd_identifier from lbrynet.dht.node import Node from lbrynet.extras.daemon.Component import Component from lbrynet.extras.daemon.ExchangeRateManager import ExchangeRateManager from lbrynet.extras.daemon.storage import SQLiteStorage from lbrynet.extras.daemon.HashAnnouncer import DHTHashAnnouncer from lbrynet.extras.reflector.server.server import ReflectorServerFactory from lbrynet.extras.wallet import LbryWalletManager from lbrynet.extras.wallet import Network from lbrynet.utils import DeferredDict, generate_id from lbrynet.p2p.PaymentRateManager import OnlyFreePaymentsManager from lbrynet.p2p.RateLimiter import RateLimiter from lbrynet.p2p.BlobManager import DiskBlobManager from lbrynet.p2p.StreamDescriptor import StreamDescriptorIdentifier, EncryptedFileStreamType from lbrynet.p2p.server.BlobRequestHandler import BlobRequestHandlerFactory from lbrynet.p2p.server.ServerProtocol import ServerProtocolFactory log = logging.getLogger(__name__) # settings must be initialized before this file is imported DATABASE_COMPONENT = "database" BLOB_COMPONENT = "blob_manager" HEADERS_COMPONENT = "blockchain_headers" WALLET_COMPONENT = "wallet" DHT_COMPONENT = "dht" HASH_ANNOUNCER_COMPONENT = "hash_announcer" FILE_MANAGER_COMPONENT = "file_manager" PEER_PROTOCOL_SERVER_COMPONENT = "peer_protocol_server" REFLECTOR_COMPONENT = "reflector" UPNP_COMPONENT = "upnp" EXCHANGE_RATE_MANAGER_COMPONENT = "exchange_rate_manager" RATE_LIMITER_COMPONENT = "rate_limiter" PAYMENT_RATE_COMPONENT = "payment_rate_manager" def from_future(coroutine: asyncio.coroutine) -> defer.Deferred: return defer.Deferred.fromFuture(asyncio.ensure_future(coroutine)) @defer.inlineCallbacks def get_external_ip(): # used if upnp is disabled or non-functioning try: buf = [] response = yield treq.get("https://api.lbry.io/ip") yield treq.collect(response, buf.append) parsed = json.loads(b"".join(buf).decode()) if parsed['success']: return parsed['data']['ip'] return except Exception as err: return class DatabaseComponent(Component): component_name = DATABASE_COMPONENT def __init__(self, component_manager): super().__init__(component_manager) self.storage = None @property def component(self): return self.storage @staticmethod def get_current_db_revision(): return 9 @staticmethod def get_revision_filename(): return conf.settings.get_db_revision_filename() @staticmethod def _write_db_revision_file(version_num): with open(conf.settings.get_db_revision_filename(), mode='w') as db_revision: db_revision.write(str(version_num)) @defer.inlineCallbacks def start(self): # check directories exist, create them if they don't log.info("Loading databases") if not os.path.exists(self.get_revision_filename()): log.warning("db_revision file not found. Creating it") self._write_db_revision_file(self.get_current_db_revision()) # check the db migration and run any needed migrations with open(self.get_revision_filename(), "r") as revision_read_handle: old_revision = int(revision_read_handle.read().strip()) if old_revision > self.get_current_db_revision(): raise Exception('This version of lbrynet is not compatible with the database\n' 'Your database is revision %i, expected %i' % (old_revision, self.get_current_db_revision())) if old_revision < self.get_current_db_revision(): from lbrynet.extras.daemon.migrator import dbmigrator log.info("Upgrading your databases (revision %i to %i)", old_revision, self.get_current_db_revision()) yield threads.deferToThread( dbmigrator.migrate_db, conf.settings.data_dir, old_revision, self.get_current_db_revision() ) self._write_db_revision_file(self.get_current_db_revision()) log.info("Finished upgrading the databases.") # start SQLiteStorage self.storage = SQLiteStorage(conf.settings.data_dir) yield self.storage.setup() @defer.inlineCallbacks def stop(self): yield self.storage.stop() self.storage = None HEADERS_URL = "https://headers.lbry.io/blockchain_headers_latest" HEADER_SIZE = 112 class HeadersComponent(Component): component_name = HEADERS_COMPONENT def __init__(self, component_manager): super().__init__(component_manager) self.headers_dir = os.path.join(conf.settings.wallet_dir, 'lbc_mainnet') self.headers_file = os.path.join(self.headers_dir, 'headers') self.old_file = os.path.join(conf.settings.wallet_dir, 'blockchain_headers') self._downloading_headers = None self._headers_progress_percent = 0 @property def component(self): return self def get_status(self): return {} if not self._downloading_headers else { 'downloading_headers': self._downloading_headers, 'download_progress': self._headers_progress_percent } @defer.inlineCallbacks def fetch_headers_from_s3(self): def collector(data, h_file): h_file.write(data) local_size = float(h_file.tell()) final_size = float(final_size_after_download) self._headers_progress_percent = math.ceil(local_size / final_size * 100) local_header_size = self.local_header_file_size() resume_header = {"Range": f"bytes={local_header_size}-"} response = yield treq.get(HEADERS_URL, headers=resume_header) got_406 = response.code == 406 # our file is bigger final_size_after_download = response.length + local_header_size if got_406: log.warning("s3 is more out of date than we are") # should have something to download and a final length divisible by the header size elif final_size_after_download and not final_size_after_download % HEADER_SIZE: s3_height = (final_size_after_download / HEADER_SIZE) - 1 local_height = self.local_header_file_height() if s3_height > local_height: if local_header_size: log.info("Resuming download of %i bytes from s3", response.length) with open(self.headers_file, "a+b") as headers_file: yield treq.collect(response, lambda d: collector(d, headers_file)) else: with open(self.headers_file, "wb") as headers_file: yield treq.collect(response, lambda d: collector(d, headers_file)) log.info("fetched headers from s3 (s3 height: %i), now verifying integrity after download.", s3_height) self._check_header_file_integrity() else: log.warning("s3 is more out of date than we are") else: log.error("invalid size for headers from s3") def local_header_file_height(self): return max((self.local_header_file_size() / HEADER_SIZE) - 1, 0) def local_header_file_size(self): if os.path.isfile(self.headers_file): return os.stat(self.headers_file).st_size return 0 async def get_remote_height(self): ledger = SimpleNamespace() ledger.config = { 'default_servers': conf.settings['lbryum_servers'], 'data_path': conf.settings.wallet_dir } net = Network(ledger) first_connection = net.on_connected.first asyncio.ensure_future(net.start()) await first_connection remote_height = await net.get_server_height() await net.stop() return remote_height async def should_download_headers_from_s3(self): if conf.settings['blockchain_name'] != "lbrycrd_main": return False self._check_header_file_integrity() s3_headers_depth = conf.settings['s3_headers_depth'] if not s3_headers_depth: return False local_height = self.local_header_file_height() remote_height = await self.get_remote_height() log.info("remote height: %i, local height: %i", remote_height, local_height) if remote_height > (local_height + s3_headers_depth): return True return False def _check_header_file_integrity(self): # TODO: temporary workaround for usability. move to txlbryum and check headers instead of file integrity if conf.settings['blockchain_name'] != "lbrycrd_main": return hashsum = sha256() checksum_height, checksum = conf.settings['HEADERS_FILE_SHA256_CHECKSUM'] checksum_length_in_bytes = checksum_height * HEADER_SIZE if self.local_header_file_size() < checksum_length_in_bytes: return with open(self.headers_file, "rb") as headers_file: hashsum.update(headers_file.read(checksum_length_in_bytes)) current_checksum = hashsum.hexdigest() if current_checksum != checksum: msg = f"Expected checksum {checksum}, got {current_checksum}" log.warning("Wallet file corrupted, checksum mismatch. " + msg) log.warning("Deleting header file so it can be downloaded again.") os.unlink(self.headers_file) elif (self.local_header_file_size() % HEADER_SIZE) != 0: log.warning("Header file is good up to checkpoint height, but incomplete. Truncating to checkpoint.") with open(self.headers_file, "rb+") as headers_file: headers_file.truncate(checksum_length_in_bytes) @defer.inlineCallbacks def start(self): conf.settings.ensure_wallet_dir() if not os.path.exists(self.headers_dir): os.mkdir(self.headers_dir) if os.path.exists(self.old_file): log.warning("Moving old headers from %s to %s.", self.old_file, self.headers_file) os.rename(self.old_file, self.headers_file) self._downloading_headers = yield f2d(self.should_download_headers_from_s3()) if self._downloading_headers: try: yield self.fetch_headers_from_s3() except Exception as err: log.error("failed to fetch headers from s3: %s", err) finally: self._downloading_headers = False def stop(self): return defer.succeed(None) def d2f(deferred): return deferred.asFuture(asyncio.get_event_loop()) def f2d(future): return defer.Deferred.fromFuture(asyncio.ensure_future(future)) class WalletComponent(Component): component_name = WALLET_COMPONENT depends_on = [DATABASE_COMPONENT, HEADERS_COMPONENT] def __init__(self, component_manager): super().__init__(component_manager) self.wallet_manager = None @property def component(self): return self.wallet_manager def get_status(self): if self.wallet_manager and self.running: local_height = self.wallet_manager.network.get_local_height() remote_height = self.wallet_manager.network.get_server_height() best_hash = self.wallet_manager.get_best_blockhash() return { 'blocks': max(local_height, 0), 'blocks_behind': max(remote_height - local_height, 0), 'best_blockhash': best_hash, 'is_encrypted': self.wallet_manager.wallet.use_encryption, 'is_locked': not self.wallet_manager.is_wallet_unlocked, } @defer.inlineCallbacks def start(self): conf.settings.ensure_wallet_dir() log.info("Starting torba wallet") storage = self.component_manager.get_component(DATABASE_COMPONENT) lbrynet.schema.BLOCKCHAIN_NAME = conf.settings['blockchain_name'] self.wallet_manager = yield f2d(LbryWalletManager.from_lbrynet_config(conf.settings, storage)) self.wallet_manager.old_db = storage yield f2d(self.wallet_manager.start()) @defer.inlineCallbacks def stop(self): yield f2d(self.wallet_manager.stop()) self.wallet_manager = None class BlobComponent(Component): component_name = BLOB_COMPONENT depends_on = [DATABASE_COMPONENT] def __init__(self, component_manager): super().__init__(component_manager) self.blob_manager = None @property def component(self): return self.blob_manager def start(self): storage = self.component_manager.get_component(DATABASE_COMPONENT) datastore = None if DHT_COMPONENT not in self.component_manager.skip_components: dht_node = self.component_manager.get_component(DHT_COMPONENT) if dht_node: datastore = dht_node._dataStore self.blob_manager = DiskBlobManager(os.path.join(conf.settings.data_dir, "blobfiles"), storage, datastore) return self.blob_manager.setup() def stop(self): return self.blob_manager.stop() @defer.inlineCallbacks def get_status(self): count = 0 if self.blob_manager: count = yield self.blob_manager.storage.count_finished_blobs() defer.returnValue({ 'finished_blobs': count }) class DHTComponent(Component): component_name = DHT_COMPONENT depends_on = [UPNP_COMPONENT] def __init__(self, component_manager): super().__init__(component_manager) self.dht_node = None self.upnp_component = None self.external_udp_port = None self.external_peer_port = None @property def component(self): return self.dht_node def get_status(self): return { 'node_id': binascii.hexlify(conf.settings.get_node_id()), 'peers_in_routing_table': 0 if not self.dht_node else len(self.dht_node.contacts) } @defer.inlineCallbacks def start(self): self.upnp_component = self.component_manager.get_component(UPNP_COMPONENT) self.external_peer_port = self.upnp_component.upnp_redirects.get("TCP", conf.settings["peer_port"]) self.external_udp_port = self.upnp_component.upnp_redirects.get("UDP", conf.settings["dht_node_port"]) node_id = conf.settings.get_node_id() if node_id is None: node_id = generate_id() external_ip = self.upnp_component.external_ip if not external_ip: log.warning("UPnP component failed to get external ip") external_ip = yield get_external_ip() if not external_ip: log.warning("failed to get external ip") self.dht_node = Node( node_id=node_id, udpPort=conf.settings['dht_node_port'], externalUDPPort=self.external_udp_port, externalIP=external_ip, peerPort=self.external_peer_port ) yield self.dht_node.start(conf.settings['known_dht_nodes'], block_on_join=False) log.info("Started the dht") @defer.inlineCallbacks def stop(self): yield self.dht_node.stop() class HashAnnouncerComponent(Component): component_name = HASH_ANNOUNCER_COMPONENT depends_on = [DHT_COMPONENT, DATABASE_COMPONENT] def __init__(self, component_manager): super().__init__(component_manager) self.hash_announcer = None @property def component(self): return self.hash_announcer @defer.inlineCallbacks def start(self): storage = self.component_manager.get_component(DATABASE_COMPONENT) dht_node = self.component_manager.get_component(DHT_COMPONENT) self.hash_announcer = DHTHashAnnouncer(dht_node, storage) yield self.hash_announcer.start() @defer.inlineCallbacks def stop(self): yield self.hash_announcer.stop() def get_status(self): return { 'announce_queue_size': 0 if not self.hash_announcer else len(self.hash_announcer.hash_queue) } class RateLimiterComponent(Component): component_name = RATE_LIMITER_COMPONENT def __init__(self, component_manager): super().__init__(component_manager) self.rate_limiter = RateLimiter() @property def component(self): return self.rate_limiter def start(self): self.rate_limiter.start() return defer.succeed(None) def stop(self): self.rate_limiter.stop() return defer.succeed(None) class PaymentRateComponent(Component): component_name = PAYMENT_RATE_COMPONENT def __init__(self, component_manager): super().__init__(component_manager) self.payment_rate_manager = OnlyFreePaymentsManager() @property def component(self): return self.payment_rate_manager def start(self): return defer.succeed(None) def stop(self): return defer.succeed(None) class FileManagerComponent(Component): component_name = FILE_MANAGER_COMPONENT depends_on = [RATE_LIMITER_COMPONENT, BLOB_COMPONENT, DATABASE_COMPONENT, WALLET_COMPONENT, PAYMENT_RATE_COMPONENT] def __init__(self, component_manager): super().__init__(component_manager) self.file_manager = None @property def component(self): return self.file_manager def get_status(self): if not self.file_manager: return return { 'managed_files': len(self.file_manager.lbry_files) } @defer.inlineCallbacks def start(self): rate_limiter = self.component_manager.get_component(RATE_LIMITER_COMPONENT) blob_manager = self.component_manager.get_component(BLOB_COMPONENT) storage = self.component_manager.get_component(DATABASE_COMPONENT) wallet = self.component_manager.get_component(WALLET_COMPONENT) sd_identifier = StreamDescriptorIdentifier() add_lbry_file_to_sd_identifier(sd_identifier) file_saver_factory = EncryptedFileSaverFactory( self.component_manager.peer_finder, rate_limiter, blob_manager, storage, wallet, conf.settings.download_dir ) yield sd_identifier.add_stream_downloader_factory(EncryptedFileStreamType, file_saver_factory) payment_rate_manager = self.component_manager.get_component(PAYMENT_RATE_COMPONENT) log.info('Starting the file manager') self.file_manager = EncryptedFileManager(self.component_manager.peer_finder, rate_limiter, blob_manager, wallet, payment_rate_manager, storage, sd_identifier) yield self.file_manager.setup() log.info('Done setting up file manager') @defer.inlineCallbacks def stop(self): yield self.file_manager.stop() class PeerProtocolServerComponent(Component): component_name = PEER_PROTOCOL_SERVER_COMPONENT depends_on = [UPNP_COMPONENT, RATE_LIMITER_COMPONENT, BLOB_COMPONENT, WALLET_COMPONENT, PAYMENT_RATE_COMPONENT] def __init__(self, component_manager): super().__init__(component_manager) self.lbry_server_port = None @property def component(self): return self.lbry_server_port @defer.inlineCallbacks def start(self): wallet = self.component_manager.get_component(WALLET_COMPONENT) upnp = self.component_manager.get_component(UPNP_COMPONENT) peer_port = conf.settings['peer_port'] query_handlers = { handler.get_primary_query_identifier(): handler for handler in [ BlobRequestHandlerFactory( self.component_manager.get_component(BLOB_COMPONENT), wallet, self.component_manager.get_component(PAYMENT_RATE_COMPONENT), self.component_manager.analytics_manager ), wallet.get_wallet_info_query_handler_factory(), ] } server_factory = ServerProtocolFactory( self.component_manager.get_component(RATE_LIMITER_COMPONENT), query_handlers, self.component_manager.peer_manager ) try: log.info("Peer protocol listening on TCP %i (ext port %i)", peer_port, upnp.upnp_redirects.get("TCP", peer_port)) self.lbry_server_port = yield reactor.listenTCP(peer_port, server_factory) except error.CannotListenError as e: import traceback log.error("Couldn't bind to port %d. Visit lbry.io/faq/how-to-change-port for" " more details.", peer_port) log.error("%s", traceback.format_exc()) raise ValueError("%s lbrynet may already be running on your computer." % str(e)) @defer.inlineCallbacks def stop(self): if self.lbry_server_port is not None: self.lbry_server_port, old_port = None, self.lbry_server_port log.info('Stop listening on port %s', old_port.port) yield old_port.stopListening() class ReflectorComponent(Component): component_name = REFLECTOR_COMPONENT depends_on = [BLOB_COMPONENT, FILE_MANAGER_COMPONENT] def __init__(self, component_manager): super().__init__(component_manager) self.reflector_server_port = conf.settings['reflector_port'] self.reflector_server = None @property def component(self): return self.reflector_server @defer.inlineCallbacks def start(self): log.info("Starting reflector server") blob_manager = self.component_manager.get_component(BLOB_COMPONENT) file_manager = self.component_manager.get_component(FILE_MANAGER_COMPONENT) reflector_factory = ReflectorServerFactory(self.component_manager.peer_manager, blob_manager, file_manager) try: self.reflector_server = yield reactor.listenTCP(self.reflector_server_port, reflector_factory) log.info('Started reflector on port %s', self.reflector_server_port) except error.CannotListenError as e: log.exception("Couldn't bind reflector to port %d", self.reflector_server_port) raise ValueError(f"{e} lbrynet may already be running on your computer.") @defer.inlineCallbacks def stop(self): if self.reflector_server is not None: log.info("Stopping reflector server") self.reflector_server, p = None, self.reflector_server yield p.stopListening class UPnPComponent(Component): component_name = UPNP_COMPONENT def __init__(self, component_manager): super().__init__(component_manager) self._int_peer_port = conf.settings['peer_port'] self._int_dht_node_port = conf.settings['dht_node_port'] self.use_upnp = conf.settings['use_upnp'] self.upnp = None self.upnp_redirects = {} self.external_ip = None self._maintain_redirects_lc = task.LoopingCall(self._maintain_redirects) self._maintain_redirects_lc.clock = self.component_manager.reactor @property def component(self): return self @defer.inlineCallbacks def _setup_redirects(self): d = {} if PEER_PROTOCOL_SERVER_COMPONENT not in self.component_manager.skip_components: d["TCP"] = from_future(self.upnp.get_next_mapping(self._int_peer_port, "TCP", "LBRY peer port")) if DHT_COMPONENT not in self.component_manager.skip_components: d["UDP"] = from_future(self.upnp.get_next_mapping(self._int_dht_node_port, "UDP", "LBRY DHT port")) upnp_redirects = yield DeferredDict(d) self.upnp_redirects.update(upnp_redirects) @defer.inlineCallbacks def _maintain_redirects(self): # setup the gateway if necessary if not self.upnp: try: self.upnp = yield from_future(UPnP.discover()) log.info("found upnp gateway: %s", self.upnp.gateway.manufacturer_string) except Exception as err: log.warning("upnp discovery failed: %s", err) self.upnp = None # update the external ip external_ip = None if self.upnp: try: external_ip = yield from_future(self.upnp.get_external_ip()) if external_ip != "0.0.0.0" and not self.external_ip: log.info("got external ip from UPnP: %s", external_ip) except (asyncio.TimeoutError, UPnPError): pass if external_ip == "0.0.0.0" or not external_ip: log.warning("unable to get external ip from UPnP, checking lbry.io fallback") external_ip = yield get_external_ip() if self.external_ip and self.external_ip != external_ip: log.info("external ip changed from %s to %s", self.external_ip, external_ip) self.external_ip = external_ip assert self.external_ip is not None # TODO: handle going/starting offline if not self.upnp_redirects and self.upnp: # setup missing redirects try: log.info("add UPnP port mappings") d = {} if PEER_PROTOCOL_SERVER_COMPONENT not in self.component_manager.skip_components: d["TCP"] = from_future(self.upnp.get_next_mapping(self._int_peer_port, "TCP", "LBRY peer port")) if DHT_COMPONENT not in self.component_manager.skip_components: d["UDP"] = from_future(self.upnp.get_next_mapping(self._int_dht_node_port, "UDP", "LBRY DHT port")) upnp_redirects = yield DeferredDict(d) log.info("set up redirects: %s", upnp_redirects) self.upnp_redirects.update(upnp_redirects) except (asyncio.TimeoutError, UPnPError): self.upnp = None return self._maintain_redirects() elif self.upnp: # check existing redirects are still active found = set() mappings = yield from_future(self.upnp.get_redirects()) for mapping in mappings: proto = mapping['NewProtocol'] if proto in self.upnp_redirects and mapping['NewExternalPort'] == self.upnp_redirects[proto]: if mapping['NewInternalClient'] == self.upnp.lan_address: found.add(proto) if 'UDP' not in found and DHT_COMPONENT not in self.component_manager.skip_components: try: udp_port = yield from_future( self.upnp.get_next_mapping(self._int_dht_node_port, "UDP", "LBRY DHT port") ) self.upnp_redirects['UDP'] = udp_port log.info("refreshed upnp redirect for dht port: %i", udp_port) except (asyncio.TimeoutError, UPnPError): del self.upnp_redirects['UDP'] if 'TCP' not in found and PEER_PROTOCOL_SERVER_COMPONENT not in self.component_manager.skip_components: try: tcp_port = yield from_future( self.upnp.get_next_mapping(self._int_peer_port, "TCP", "LBRY peer port") ) self.upnp_redirects['TCP'] = tcp_port log.info("refreshed upnp redirect for peer port: %i", tcp_port) except (asyncio.TimeoutError, UPnPError): del self.upnp_redirects['TCP'] if ('TCP' in self.upnp_redirects and PEER_PROTOCOL_SERVER_COMPONENT not in self.component_manager.skip_components) and ( 'UDP' in self.upnp_redirects and DHT_COMPONENT not in self.component_manager.skip_components): if self.upnp_redirects: log.debug("upnp redirects are still active") @defer.inlineCallbacks def start(self): log.info("detecting external ip") if not self.use_upnp: self.external_ip = yield get_external_ip() return success = False yield self._maintain_redirects() if self.upnp: if not self.upnp_redirects and not all([x in self.component_manager.skip_components for x in (DHT_COMPONENT, PEER_PROTOCOL_SERVER_COMPONENT)]): log.error("failed to setup upnp, debugging infomation: %s", self.upnp.zipped_debugging_info) else: success = True if self.upnp_redirects: log.debug("set up upnp port redirects for gateway: %s", self.upnp.gateway.manufacturer_string) else: log.error("failed to setup upnp") self.component_manager.analytics_manager.send_upnp_setup_success_fail(success, self.get_status()) self._maintain_redirects_lc.start(360, now=False) def stop(self): if self._maintain_redirects_lc.running: self._maintain_redirects_lc.stop() return defer.DeferredList( [from_future(self.upnp.delete_port_mapping(port, protocol)) for protocol, port in self.upnp_redirects.items()] ) def get_status(self): return { 'aioupnp_version': aioupnp_version, 'redirects': self.upnp_redirects, 'gateway': 'No gateway found' if not self.upnp else self.upnp.gateway.manufacturer_string, 'dht_redirect_set': 'UDP' in self.upnp_redirects, 'peer_redirect_set': 'TCP' in self.upnp_redirects, 'external_ip': self.external_ip } class ExchangeRateManagerComponent(Component): component_name = EXCHANGE_RATE_MANAGER_COMPONENT def __init__(self, component_manager): Component.__init__(self, component_manager) self.exchange_rate_manager = ExchangeRateManager() @property def component(self): return self.exchange_rate_manager @defer.inlineCallbacks def start(self): yield self.exchange_rate_manager.start() @defer.inlineCallbacks def stop(self): yield self.exchange_rate_manager.stop()