py-libp2p/libp2p/host/basic_host.py
2019-11-07 20:57:43 -08:00

180 lines
6.2 KiB
Python

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