196 lines
6.8 KiB
Python
196 lines
6.8 KiB
Python
import logging
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from typing import TYPE_CHECKING, AsyncIterator, List, Sequence
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from async_generator import asynccontextmanager
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from async_service import background_trio_service
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import multiaddr
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from libp2p.crypto.keys import PrivateKey, PublicKey
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from libp2p.host.defaults import get_default_protocols
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from libp2p.host.exceptions import StreamFailure
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from libp2p.network.network_interface import INetworkService
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from libp2p.network.stream.net_stream_interface import INetStream
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from libp2p.peer.id import ID
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from libp2p.peer.peerinfo import PeerInfo
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from libp2p.peer.peerstore_interface import IPeerStore
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from libp2p.protocol_muxer.exceptions import MultiselectClientError, MultiselectError
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from libp2p.protocol_muxer.multiselect import Multiselect
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from libp2p.protocol_muxer.multiselect_client import MultiselectClient
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from libp2p.protocol_muxer.multiselect_communicator import MultiselectCommunicator
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from libp2p.typing import StreamHandlerFn, TProtocol
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from .host_interface import IHost
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if TYPE_CHECKING:
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from collections import OrderedDict
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# Upon host creation, host takes in options,
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# including the list of addresses on which to listen.
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# Host then parses these options and delegates to its Network instance,
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# telling it to listen on the given listen addresses.
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logger = logging.getLogger("libp2p.network.basic_host")
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class BasicHost(IHost):
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"""
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BasicHost is a wrapper of a `INetwork` implementation.
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It performs protocol negotiation on a stream with multistream-select
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right after a stream is initialized.
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"""
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_network: INetworkService
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peerstore: IPeerStore
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multiselect: Multiselect
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multiselect_client: MultiselectClient
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def __init__(
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self,
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network: INetworkService,
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default_protocols: "OrderedDict[TProtocol, StreamHandlerFn]" = None,
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) -> None:
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self._network = network
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self._network.set_stream_handler(self._swarm_stream_handler)
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self.peerstore = self._network.peerstore
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# Protocol muxing
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default_protocols = default_protocols or get_default_protocols(self)
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self.multiselect = Multiselect(default_protocols)
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self.multiselect_client = MultiselectClient()
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def get_id(self) -> ID:
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"""
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:return: peer_id of host
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"""
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return self._network.get_peer_id()
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def get_public_key(self) -> PublicKey:
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return self.peerstore.pubkey(self.get_id())
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def get_private_key(self) -> PrivateKey:
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return self.peerstore.privkey(self.get_id())
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def get_network(self) -> INetworkService:
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"""
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:return: network instance of host
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"""
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return self._network
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def get_peerstore(self) -> IPeerStore:
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"""
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:return: peerstore of the host (same one as in its network instance)
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"""
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return self.peerstore
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def get_mux(self) -> Multiselect:
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"""
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:return: mux instance of host
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"""
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return self.multiselect
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def get_addrs(self) -> List[multiaddr.Multiaddr]:
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"""
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:return: all the multiaddr addresses this host is listening to
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"""
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# TODO: We don't need "/p2p/{peer_id}" postfix actually.
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p2p_part = multiaddr.Multiaddr("/p2p/{}".format(self.get_id().pretty()))
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addrs: List[multiaddr.Multiaddr] = []
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for transport in self._network.listeners.values():
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for addr in transport.get_addrs():
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addrs.append(addr.encapsulate(p2p_part))
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return addrs
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@asynccontextmanager
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async def run(
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self, listen_addrs: Sequence[multiaddr.Multiaddr]
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) -> AsyncIterator[None]:
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"""
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run the host instance and listen to ``listen_addrs``.
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:param listen_addrs: a sequence of multiaddrs that we want to listen to
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"""
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network = self.get_network()
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async with background_trio_service(network):
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await network.listen(*listen_addrs)
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yield
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def set_stream_handler(
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self, protocol_id: TProtocol, stream_handler: StreamHandlerFn
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) -> None:
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"""
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set stream handler for given `protocol_id`
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:param protocol_id: protocol id used on stream
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:param stream_handler: a stream handler function
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"""
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self.multiselect.add_handler(protocol_id, stream_handler)
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async def new_stream(
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self, peer_id: ID, protocol_ids: Sequence[TProtocol]
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) -> INetStream:
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"""
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:param peer_id: peer_id that host is connecting
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:param protocol_ids: available protocol ids to use for stream
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:return: stream: new stream created
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"""
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net_stream = await self._network.new_stream(peer_id)
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# Perform protocol muxing to determine protocol to use
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try:
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selected_protocol = await self.multiselect_client.select_one_of(
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list(protocol_ids), MultiselectCommunicator(net_stream)
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)
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except MultiselectClientError as error:
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logger.debug("fail to open a stream to peer %s, error=%s", peer_id, error)
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await net_stream.reset()
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raise StreamFailure("failt to open a stream to peer %s", peer_id) from error
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net_stream.set_protocol(selected_protocol)
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return net_stream
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async def connect(self, peer_info: PeerInfo) -> None:
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"""
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connect ensures there is a connection between this host and the peer
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with given `peer_info.peer_id`. connect will absorb the addresses in
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peer_info into its internal peerstore. If there is not an active
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connection, connect will issue a dial, and block until a connection is
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opened, or an error is returned.
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:param peer_info: peer_info of the peer we want to connect to
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:type peer_info: peer.peerinfo.PeerInfo
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"""
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self.peerstore.add_addrs(peer_info.peer_id, peer_info.addrs, 10)
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# there is already a connection to this peer
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if peer_info.peer_id in self._network.connections:
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return
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await self._network.dial_peer(peer_info.peer_id)
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async def disconnect(self, peer_id: ID) -> None:
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await self._network.close_peer(peer_id)
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async def close(self) -> None:
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await self._network.close()
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# Reference: `BasicHost.newStreamHandler` in Go.
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async def _swarm_stream_handler(self, net_stream: INetStream) -> None:
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# Perform protocol muxing to determine protocol to use
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try:
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protocol, handler = await self.multiselect.negotiate(
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MultiselectCommunicator(net_stream)
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)
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except MultiselectError as error:
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peer_id = net_stream.muxed_conn.peer_id
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logger.debug(
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"failed to accept a stream from peer %s, error=%s", peer_id, error
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)
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await net_stream.reset()
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return
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net_stream.set_protocol(protocol)
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await handler(net_stream)
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