lbry-sdk/lbry/dht/node.py
2022-08-11 20:38:42 -03:00

289 lines
15 KiB
Python

import logging
import asyncio
import typing
import socket
from prometheus_client import Gauge
from lbry.utils import aclosing, resolve_host
from lbry.dht import constants
from lbry.dht.peer import make_kademlia_peer
from lbry.dht.protocol.distance import Distance
from lbry.dht.protocol.iterative_find import IterativeNodeFinder, IterativeValueFinder
from lbry.dht.protocol.protocol import KademliaProtocol
if typing.TYPE_CHECKING:
from lbry.dht.peer import PeerManager
from lbry.dht.peer import KademliaPeer
log = logging.getLogger(__name__)
class Node:
storing_peers_metric = Gauge(
"storing_peers", "Number of peers storing blobs announced to this node", namespace="dht_node",
labelnames=("scope",),
)
stored_blob_with_x_bytes_colliding = Gauge(
"stored_blobs_x_bytes_colliding", "Number of blobs with at least X bytes colliding with this node id prefix",
namespace="dht_node", labelnames=("amount",)
)
def __init__(self, loop: asyncio.AbstractEventLoop, peer_manager: 'PeerManager', node_id: bytes, udp_port: int,
internal_udp_port: int, peer_port: int, external_ip: str, rpc_timeout: float = constants.RPC_TIMEOUT,
split_buckets_under_index: int = constants.SPLIT_BUCKETS_UNDER_INDEX,
storage: typing.Optional['SQLiteStorage'] = None):
self.loop = loop
self.internal_udp_port = internal_udp_port
self.protocol = KademliaProtocol(loop, peer_manager, node_id, external_ip, udp_port, peer_port, rpc_timeout,
split_buckets_under_index)
self.listening_port: asyncio.DatagramTransport = None
self.joined = asyncio.Event(loop=self.loop)
self._join_task: asyncio.Task = None
self._refresh_task: asyncio.Task = None
self._storage = storage
@property
def stored_blob_hashes(self):
return self.protocol.data_store.keys()
async def refresh_node(self, force_once=False):
while True:
# remove peers with expired blob announcements from the datastore
self.protocol.data_store.removed_expired_peers()
total_peers: typing.List['KademliaPeer'] = []
# add all peers in the routing table
total_peers.extend(self.protocol.routing_table.get_peers())
# add all the peers who have announced blobs to us
storing_peers = self.protocol.data_store.get_storing_contacts()
self.storing_peers_metric.labels("global").set(len(storing_peers))
total_peers.extend(storing_peers)
counts = {0: 0, 1: 0, 2: 0}
node_id = self.protocol.node_id
for blob_hash in self.protocol.data_store.keys():
bytes_colliding = 0 if blob_hash[0] != node_id[0] else 2 if blob_hash[1] == node_id[1] else 1
counts[bytes_colliding] += 1
self.stored_blob_with_x_bytes_colliding.labels(amount=0).set(counts[0])
self.stored_blob_with_x_bytes_colliding.labels(amount=1).set(counts[1])
self.stored_blob_with_x_bytes_colliding.labels(amount=2).set(counts[2])
# get ids falling in the midpoint of each bucket that hasn't been recently updated
node_ids = self.protocol.routing_table.get_refresh_list(0, True)
# if we have 3 or fewer populated buckets get two random ids in the range of each to try and
# populate/split the buckets further
buckets_with_contacts = self.protocol.routing_table.buckets_with_contacts()
if buckets_with_contacts <= 3:
for i in range(buckets_with_contacts):
node_ids.append(self.protocol.routing_table.random_id_in_bucket_range(i))
node_ids.append(self.protocol.routing_table.random_id_in_bucket_range(i))
if self.protocol.routing_table.get_peers():
# if we have node ids to look up, perform the iterative search until we have k results
while node_ids:
peers = await self.peer_search(node_ids.pop())
total_peers.extend(peers)
else:
if force_once:
break
fut = asyncio.Future(loop=self.loop)
self.loop.call_later(constants.REFRESH_INTERVAL // 4, fut.set_result, None)
await fut
continue
# ping the set of peers; upon success/failure the routing able and last replied/failed time will be updated
to_ping = [peer for peer in set(total_peers) if self.protocol.peer_manager.peer_is_good(peer) is not True]
if to_ping:
self.protocol.ping_queue.enqueue_maybe_ping(*to_ping, delay=0)
if self._storage:
await self._storage.save_kademlia_peers(self.protocol.routing_table.get_peers())
if force_once:
break
fut = asyncio.Future(loop=self.loop)
self.loop.call_later(constants.REFRESH_INTERVAL, fut.set_result, None)
await fut
async def announce_blob(self, blob_hash: str) -> typing.List[bytes]:
hash_value = bytes.fromhex(blob_hash)
assert len(hash_value) == constants.HASH_LENGTH
peers = await self.peer_search(hash_value)
if not self.protocol.external_ip:
raise Exception("Cannot determine external IP")
log.debug("Store to %i peers", len(peers))
for peer in peers:
log.debug("store to %s %s %s", peer.address, peer.udp_port, peer.tcp_port)
stored_to_tup = await asyncio.gather(
*(self.protocol.store_to_peer(hash_value, peer) for peer in peers), loop=self.loop
)
stored_to = [node_id for node_id, contacted in stored_to_tup if contacted]
if stored_to:
log.debug(
"Stored %s to %i of %i attempted peers", hash_value.hex()[:8],
len(stored_to), len(peers)
)
else:
log.debug("Failed announcing %s, stored to 0 peers", blob_hash[:8])
return stored_to
def stop(self) -> None:
if self.joined.is_set():
self.joined.clear()
if self._join_task:
self._join_task.cancel()
if self._refresh_task and not (self._refresh_task.done() or self._refresh_task.cancelled()):
self._refresh_task.cancel()
if self.protocol and self.protocol.ping_queue.running:
self.protocol.ping_queue.stop()
self.protocol.stop()
if self.listening_port is not None:
self.listening_port.close()
self._join_task = None
self.listening_port = None
log.info("Stopped DHT node")
async def start_listening(self, interface: str = '0.0.0.0') -> None:
if not self.listening_port:
self.listening_port, _ = await self.loop.create_datagram_endpoint(
lambda: self.protocol, (interface, self.internal_udp_port)
)
log.info("DHT node listening on UDP %s:%i", interface, self.internal_udp_port)
self.protocol.start()
else:
log.warning("Already bound to port %s", self.listening_port)
async def join_network(self, interface: str = '0.0.0.0',
known_node_urls: typing.Optional[typing.List[typing.Tuple[str, int]]] = None):
def peers_from_urls(urls: typing.Optional[typing.List[typing.Tuple[bytes, str, int, int]]]):
peer_addresses = []
for node_id, address, udp_port, tcp_port in urls:
if (node_id, address, udp_port, tcp_port) not in peer_addresses and \
(address, udp_port) != (self.protocol.external_ip, self.protocol.udp_port):
peer_addresses.append((node_id, address, udp_port, tcp_port))
return [make_kademlia_peer(*peer_address) for peer_address in peer_addresses]
if not self.listening_port:
await self.start_listening(interface)
self.protocol.ping_queue.start()
self._refresh_task = self.loop.create_task(self.refresh_node())
while True:
if self.protocol.routing_table.get_peers():
if not self.joined.is_set():
self.joined.set()
log.info(
"joined dht, %i peers known in %i buckets", len(self.protocol.routing_table.get_peers()),
self.protocol.routing_table.buckets_with_contacts()
)
else:
if self.joined.is_set():
self.joined.clear()
seed_peers = peers_from_urls(
await self._storage.get_persisted_kademlia_peers()
) if self._storage else []
if not seed_peers:
try:
seed_peers.extend(peers_from_urls([
(None, await resolve_host(address, udp_port, 'udp'), udp_port, None)
for address, udp_port in known_node_urls or []
]))
except socket.gaierror:
await asyncio.sleep(30, loop=self.loop)
continue
self.protocol.peer_manager.reset()
self.protocol.ping_queue.enqueue_maybe_ping(*seed_peers, delay=0.0)
await self.peer_search(self.protocol.node_id, shortlist=seed_peers, count=32)
await asyncio.sleep(1, loop=self.loop)
def start(self, interface: str, known_node_urls: typing.Optional[typing.List[typing.Tuple[str, int]]] = None):
self._join_task = self.loop.create_task(self.join_network(interface, known_node_urls))
def get_iterative_node_finder(self, key: bytes, shortlist: typing.Optional[typing.List['KademliaPeer']] = None,
max_results: int = constants.K) -> IterativeNodeFinder:
shortlist = shortlist or self.protocol.routing_table.find_close_peers(key)
return IterativeNodeFinder(self.loop, self.protocol, key, max_results, shortlist)
def get_iterative_value_finder(self, key: bytes, shortlist: typing.Optional[typing.List['KademliaPeer']] = None,
max_results: int = -1) -> IterativeValueFinder:
shortlist = shortlist or self.protocol.routing_table.find_close_peers(key)
return IterativeValueFinder(self.loop, self.protocol, key, max_results, shortlist)
async def peer_search(self, node_id: bytes, count=constants.K, max_results=constants.K * 2,
shortlist: typing.Optional[typing.List['KademliaPeer']] = None
) -> typing.List['KademliaPeer']:
peers = []
async with aclosing(self.get_iterative_node_finder(
node_id, shortlist=shortlist, max_results=max_results)) as node_finder:
async for iteration_peers in node_finder:
peers.extend(iteration_peers)
distance = Distance(node_id)
peers.sort(key=lambda peer: distance(peer.node_id))
return peers[:count]
async def _accumulate_peers_for_value(self, search_queue: asyncio.Queue, result_queue: asyncio.Queue):
tasks = []
try:
while True:
blob_hash = await search_queue.get()
tasks.append(self.loop.create_task(self._peers_for_value_producer(blob_hash, result_queue)))
finally:
for task in tasks:
task.cancel()
async def _peers_for_value_producer(self, blob_hash: str, result_queue: asyncio.Queue):
async def put_into_result_queue_after_pong(_peer):
try:
await self.protocol.get_rpc_peer(_peer).ping()
result_queue.put_nowait([_peer])
log.debug("pong from %s:%i for %s", _peer.address, _peer.udp_port, blob_hash)
except asyncio.TimeoutError:
pass
# prioritize peers who reply to a dht ping first
# this minimizes attempting to make tcp connections that won't work later to dead or unreachable peers
async with aclosing(self.get_iterative_value_finder(bytes.fromhex(blob_hash))) as value_finder:
async for results in value_finder:
to_put = []
for peer in results:
if peer.address == self.protocol.external_ip and self.protocol.peer_port == peer.tcp_port:
continue
is_good = self.protocol.peer_manager.peer_is_good(peer)
if is_good:
# the peer has replied recently over UDP, it can probably be reached on the TCP port
to_put.append(peer)
elif is_good is None:
if not peer.udp_port:
# TODO: use the same port for TCP and UDP
# the udp port must be guessed
# default to the ports being the same. if the TCP port appears to be <=0.48.0 default,
# including on a network with several nodes, then assume the udp port is proportionately
# based on a starting port of 4444
udp_port_to_try = peer.tcp_port
if 3400 > peer.tcp_port > 3332:
udp_port_to_try = (peer.tcp_port - 3333) + 4444
self.loop.create_task(put_into_result_queue_after_pong(
make_kademlia_peer(peer.node_id, peer.address, udp_port_to_try, peer.tcp_port)
))
else:
self.loop.create_task(put_into_result_queue_after_pong(peer))
else:
# the peer is known to be bad/unreachable, skip trying to connect to it over TCP
log.debug("skip bad peer %s:%i for %s", peer.address, peer.tcp_port, blob_hash)
if to_put:
result_queue.put_nowait(to_put)
def accumulate_peers(self, search_queue: asyncio.Queue,
peer_queue: typing.Optional[asyncio.Queue] = None
) -> typing.Tuple[asyncio.Queue, asyncio.Task]:
queue = peer_queue or asyncio.Queue(loop=self.loop)
return queue, self.loop.create_task(self._accumulate_peers_for_value(search_queue, queue))
async def get_kademlia_peers_from_hosts(peer_list: typing.List[typing.Tuple[str, int]]) -> typing.List['KademliaPeer']:
peer_address_list = [(await resolve_host(url, port, proto='tcp'), port) for url, port in peer_list]
kademlia_peer_list = [make_kademlia_peer(None, address, None, tcp_port=port, allow_localhost=True)
for address, port in peer_address_list]
return kademlia_peer_list