py-libp2p/libp2p/network/swarm.py
mhchia 3372c32432
Fix examples and modify new_node
- Fix examples `chat.py` and `echo.py`
    - Use trio directly, instead of `trio-asyncio`
    - Remove redundant code
- Change entry API `new_node` to `new_host_trio`
2019-12-24 18:03:18 +08:00

347 lines
13 KiB
Python

import logging
from typing import Dict, List, Optional
from multiaddr import Multiaddr
import trio
from libp2p.io.abc import ReadWriteCloser
from libp2p.network.connection.net_connection_interface import INetConn
from libp2p.peer.id import ID
from libp2p.peer.peerstore import PeerStoreError
from libp2p.peer.peerstore_interface import IPeerStore
from libp2p.stream_muxer.abc import IMuxedConn
from libp2p.transport.exceptions import (
MuxerUpgradeFailure,
OpenConnectionError,
SecurityUpgradeFailure,
)
from libp2p.transport.listener_interface import IListener
from libp2p.transport.transport_interface import ITransport
from libp2p.transport.upgrader import TransportUpgrader
from libp2p.typing import StreamHandlerFn
from ..exceptions import MultiError
from .connection.raw_connection import RawConnection
from .connection.swarm_connection import SwarmConn
from .exceptions import SwarmException
from .network_interface import INetworkService
from .notifee_interface import INotifee
from .stream.net_stream_interface import INetStream
logger = logging.getLogger("libp2p.network.swarm")
class Swarm(INetworkService):
self_id: ID
peerstore: IPeerStore
upgrader: TransportUpgrader
transport: ITransport
# TODO: Connection and `peer_id` are 1-1 mapping in our implementation,
# whereas in Go one `peer_id` may point to multiple connections.
connections: Dict[ID, INetConn]
listeners: Dict[str, IListener]
common_stream_handler: Optional[StreamHandlerFn]
notifees: List[INotifee]
event_closed: trio.Event
def __init__(
self,
peer_id: ID,
peerstore: IPeerStore,
upgrader: TransportUpgrader,
transport: ITransport,
):
self.self_id = peer_id
self.peerstore = peerstore
self.upgrader = upgrader
self.transport = transport
self.connections = dict()
self.listeners = dict()
# Create Notifee array
self.notifees = []
self.event_closed = trio.Event()
self.common_stream_handler = None
async def run(self) -> None:
await self.manager.wait_finished()
def get_peer_id(self) -> ID:
return self.self_id
def set_stream_handler(self, stream_handler: StreamHandlerFn) -> None:
self.common_stream_handler = stream_handler
async def dial_peer(self, peer_id: ID) -> INetConn:
"""
dial_peer try to create a connection to peer_id.
:param peer_id: peer if we want to dial
:raises SwarmException: raised when an error occurs
:return: muxed connection
"""
if peer_id in self.connections:
# If muxed connection already exists for peer_id,
# set muxed connection equal to existing muxed connection
return self.connections[peer_id]
logger.debug("attempting to dial peer %s", peer_id)
try:
# Get peer info from peer store
addrs = self.peerstore.addrs(peer_id)
except PeerStoreError as error:
raise SwarmException(f"No known addresses to peer {peer_id}") from error
if not addrs:
raise SwarmException(f"No known addresses to peer {peer_id}")
exceptions: List[SwarmException] = []
# Try all known addresses
for multiaddr in addrs:
try:
return await self.dial_addr(multiaddr, peer_id)
except SwarmException as e:
exceptions.append(e)
logger.debug(
"encountered swarm exception when trying to connect to %s, "
"trying next address...",
multiaddr,
exc_info=e,
)
# Tried all addresses, raising exception.
raise SwarmException(
f"unable to connect to {peer_id}, no addresses established a successful connection "
"(with exceptions)"
) from MultiError(exceptions)
async def dial_addr(self, addr: Multiaddr, peer_id: ID) -> INetConn:
"""
dial_addr try to create a connection to peer_id with addr.
:param addr: the address we want to connect with
:param peer_id: the peer we want to connect to
:raises SwarmException: raised when an error occurs
:return: network connection
"""
# Dial peer (connection to peer does not yet exist)
# Transport dials peer (gets back a raw conn)
try:
raw_conn = await self.transport.dial(addr)
except OpenConnectionError as error:
logger.debug("fail to dial peer %s over base transport", peer_id)
raise SwarmException(
f"fail to open connection to peer {peer_id}"
) from error
logger.debug("dialed peer %s over base transport", peer_id)
# Per, https://discuss.libp2p.io/t/multistream-security/130, we first secure
# the conn and then mux the conn
try:
secured_conn = await self.upgrader.upgrade_security(raw_conn, peer_id, True)
except SecurityUpgradeFailure as error:
error_msg = "fail to upgrade security for peer %s"
logger.debug(error_msg, peer_id)
await raw_conn.close()
raise SwarmException(error_msg % peer_id) from error
logger.debug("upgraded security for peer %s", peer_id)
try:
muxed_conn = await self.upgrader.upgrade_connection(secured_conn, peer_id)
self.manager.run_child_service(muxed_conn)
except MuxerUpgradeFailure as error:
error_msg = "fail to upgrade mux for peer %s"
logger.debug(error_msg, peer_id)
await secured_conn.close()
raise SwarmException(error_msg % peer_id) from error
logger.debug("upgraded mux for peer %s", peer_id)
swarm_conn = await self.add_conn(muxed_conn)
logger.debug("successfully dialed peer %s", peer_id)
return swarm_conn
async def new_stream(self, peer_id: ID) -> INetStream:
"""
:param peer_id: peer_id of destination
:raises SwarmException: raised when an error occurs
:return: net stream instance
"""
logger.debug("attempting to open a stream to peer %s", peer_id)
swarm_conn = await self.dial_peer(peer_id)
net_stream = await swarm_conn.new_stream()
logger.debug("successfully opened a stream to peer %s", peer_id)
return net_stream
async def listen(self, *multiaddrs: Multiaddr) -> bool:
"""
:param multiaddrs: one or many multiaddrs to start listening on
:return: true if at least one success
For each multiaddr
- Check if a listener for multiaddr exists already
- If listener already exists, continue
- Otherwise:
- Capture multiaddr in conn handler
- Have conn handler delegate to stream handler
- Call listener listen with the multiaddr
- Map multiaddr to listener
"""
for maddr in multiaddrs:
if str(maddr) in self.listeners:
return True
async def conn_handler(read_write_closer: ReadWriteCloser) -> None:
raw_conn = RawConnection(read_write_closer, False)
# Per, https://discuss.libp2p.io/t/multistream-security/130, we first secure
# the conn and then mux the conn
try:
# FIXME: This dummy `ID(b"")` for the remote peer is useless.
secured_conn = await self.upgrader.upgrade_security(
raw_conn, ID(b""), False
)
except SecurityUpgradeFailure as error:
await raw_conn.close()
raise SwarmException() from error
peer_id = secured_conn.get_remote_peer()
try:
muxed_conn = await self.upgrader.upgrade_connection(
secured_conn, peer_id
)
self.manager.run_child_service(muxed_conn)
except MuxerUpgradeFailure as error:
error_msg = "fail to upgrade mux for peer %s"
logger.debug(error_msg, peer_id)
await secured_conn.close()
raise SwarmException(error_msg % peer_id) from error
logger.debug("upgraded mux for peer %s", peer_id)
await self.add_conn(muxed_conn)
logger.debug("successfully opened connection to peer %s", peer_id)
# NOTE: This is a intentional barrier to prevent from the handler exiting and
# closing the connection.
await self.manager.wait_finished()
try:
# Success
listener = self.transport.create_listener(conn_handler)
self.listeners[str(maddr)] = listener
# TODO: `listener.listen` is not bounded with nursery. If we want to be
# I/O agnostic, we should change the API.
await listener.listen(maddr, self.manager._task_nursery) # type: ignore
# Call notifiers since event occurred
await self.notify_listen(maddr)
return True
except IOError:
# Failed. Continue looping.
logger.debug("fail to listen on: " + str(maddr))
# No maddr succeeded
return False
async def close(self) -> None:
if self.event_closed.is_set():
return
self.event_closed.set()
# Reference: https://github.com/libp2p/go-libp2p-swarm/blob/8be680aef8dea0a4497283f2f98470c2aeae6b65/swarm.go#L124-L134 # noqa: E501
async with trio.open_nursery() as nursery:
for conn in self.connections.values():
nursery.start_soon(conn.close)
async with trio.open_nursery() as nursery:
for listener in self.listeners.values():
nursery.start_soon(listener.close)
# Cancel tasks
await self.manager.stop()
logger.debug("swarm successfully closed")
async def close_peer(self, peer_id: ID) -> None:
if peer_id not in self.connections:
return
# TODO: Should be changed to close multisple connections,
# if we have several connections per peer in the future.
connection = self.connections[peer_id]
# NOTE: `connection.close` will delete `peer_id` from `self.connections`
# and `notify_disconnected` for us.
await connection.close()
logger.debug("successfully close the connection to peer %s", peer_id)
async def add_conn(self, muxed_conn: IMuxedConn) -> SwarmConn:
"""Add a `IMuxedConn` to `Swarm` as a `SwarmConn`, notify "connected",
and start to monitor the connection for its new streams and
disconnection."""
swarm_conn = SwarmConn(muxed_conn, self)
manager = self.manager.run_child_service(swarm_conn)
# Store muxed_conn with peer id
self.connections[muxed_conn.peer_id] = swarm_conn
# Call notifiers since event occurred
self.manager.run_task(self.notify_connected, swarm_conn)
await manager.wait_started()
return swarm_conn
def remove_conn(self, swarm_conn: SwarmConn) -> None:
"""Simply remove the connection from Swarm's records, without closing
the connection."""
peer_id = swarm_conn.muxed_conn.peer_id
if peer_id not in self.connections:
return
# TODO: Should be changed to remove the exact connection,
# if we have several connections per peer in the future.
del self.connections[peer_id]
# Notifee
def register_notifee(self, notifee: INotifee) -> None:
"""
:param notifee: object implementing Notifee interface
:return: true if notifee registered successfully, false otherwise
"""
self.notifees.append(notifee)
# TODO: Use `run_task`.
async def notify_opened_stream(self, stream: INetStream) -> None:
async with trio.open_nursery() as nursery:
for notifee in self.notifees:
nursery.start_soon(notifee.opened_stream, self, stream)
# TODO: `notify_closed_stream`
async def notify_connected(self, conn: INetConn) -> None:
async with trio.open_nursery() as nursery:
for notifee in self.notifees:
nursery.start_soon(notifee.connected, self, conn)
async def notify_disconnected(self, conn: INetConn) -> None:
async with trio.open_nursery() as nursery:
for notifee in self.notifees:
nursery.start_soon(notifee.disconnected, self, conn)
async def notify_listen(self, multiaddr: Multiaddr) -> None:
async with trio.open_nursery() as nursery:
for notifee in self.notifees:
nursery.start_soon(notifee.listen, self, multiaddr)
# TODO: `notify_listen_close`