py-libp2p/libp2p/pubsub/floodsub.py
2019-07-26 18:35:25 +08:00

120 lines
4.0 KiB
Python

from typing import (
Iterable,
)
from libp2p.peer.id import (
ID,
id_b58_decode,
)
from .pb import rpc_pb2
from .pubsub_router_interface import IPubsubRouter
class FloodSub(IPubsubRouter):
# pylint: disable=no-member
def __init__(self, protocols):
self.protocols = protocols
self.pubsub = None
def get_protocols(self):
"""
:return: the list of protocols supported by the router
"""
return self.protocols
def attach(self, pubsub):
"""
Attach is invoked by the PubSub constructor to attach the router to a
freshly initialized PubSub instance.
:param pubsub: pubsub instance to attach to
"""
self.pubsub = pubsub
def add_peer(self, peer_id, protocol_id):
"""
Notifies the router that a new peer has been connected
:param peer_id: id of peer to add
"""
def remove_peer(self, peer_id):
"""
Notifies the router that a peer has been disconnected
:param peer_id: id of peer to remove
"""
async def handle_rpc(self, rpc, sender_peer_id):
"""
Invoked to process control messages in the RPC envelope.
It is invoked after subscriptions and payload messages have been processed
:param rpc: rpc message
"""
async def publish(self, src: ID, pubsub_msg: rpc_pb2.Message) -> None:
"""
Invoked to forward a new message that has been validated.
This is where the "flooding" part of floodsub happens
With flooding, routing is almost trivial: for each incoming message,
forward to all known peers in the topic. There is a bit of logic,
as the router maintains a timed cache of previous messages,
so that seen messages are not further forwarded.
It also never forwards a message back to the source
or the peer that forwarded the message.
:param src: the peer id of the peer who forwards the message to me.
:param pubsub_msg: pubsub message in protobuf.
"""
peers_gen = self._get_peers_to_send(
pubsub_msg.topicIDs,
src=src,
origin=ID(pubsub_msg.from_id),
)
rpc_msg = rpc_pb2.RPC(
publish=[pubsub_msg],
)
for peer_id in peers_gen:
stream = self.pubsub.peers[str(peer_id)]
# FIXME: We should add a `WriteMsg` similar to write delimited messages.
# Ref: https://github.com/libp2p/go-libp2p-pubsub/blob/master/comm.go#L107
await stream.write(rpc_msg.SerializeToString())
async def join(self, topic):
"""
Join notifies the router that we want to receive and
forward messages in a topic. It is invoked after the
subscription announcement
:param topic: topic to join
"""
async def leave(self, topic):
"""
Leave notifies the router that we are no longer interested in a topic.
It is invoked after the unsubscription announcement.
:param topic: topic to leave
"""
def _get_peers_to_send(
self,
topic_ids: Iterable[str],
src: ID,
origin: ID) -> Iterable[ID]:
"""
Get the eligible peers to send the data to.
:param src: the peer id of the peer who forwards the message to me.
:param origin: the peer id of the peer who originally broadcast the message.
:return: a generator of the peer ids who we send data to.
"""
for topic in topic_ids:
if topic not in self.pubsub.peer_topics:
continue
for peer_id_str in self.pubsub.peer_topics[topic]:
peer_id = id_b58_decode(peer_id_str)
if peer_id in (src, origin):
continue
# FIXME: Should change `self.pubsub.peers` to Dict[PeerID, ...]
if str(peer_id) not in self.pubsub.peers:
continue
yield peer_id