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