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Merge pull request #373 from NIC619/refactor_and_cleanup_gossipsub

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Refactor and cleanup gossipsub
This commit is contained in:
NIC Lin
2019-12-07 16:28:55 +08:00
committed by GitHub
parent 82dcce214a a675da52ee
commit ad379221b9
5 changed files with 322 additions and 93 deletions
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260
libp2p/pubsub/gossipsub.py
View File

@ -1,8 +1,9 @@
from ast import literal_eval
import asyncio
from collections import defaultdict
import logging
import random
from typing import Any, Dict, Iterable, List, Sequence, Set
from typing import Any, DefaultDict, Dict, Iterable, List, Sequence, Tuple
from libp2p.network.stream.exceptions import StreamClosed
from libp2p.peer.id import ID
@ -43,6 +44,7 @@ class GossipSub(IPubsubRouter):
mcache: MessageCache
heartbeat_initial_delay: float
heartbeat_interval: int
def __init__(
@ -54,6 +56,7 @@ class GossipSub(IPubsubRouter):
time_to_live: int,
gossip_window: int = 3,
gossip_history: int = 5,
heartbeat_initial_delay: float = 0.1,
heartbeat_interval: int = 120,
) -> None:
self.protocols = list(protocols)
@ -84,6 +87,7 @@ class GossipSub(IPubsubRouter):
self.mcache = MessageCache(gossip_window, gossip_history)
# Create heartbeat timer
self.heartbeat_initial_delay = heartbeat_initial_delay
self.heartbeat_interval = heartbeat_interval
# Interface functions
@ -106,7 +110,6 @@ class GossipSub(IPubsubRouter):
logger.debug("attached to pusub")
# Start heartbeat now that we have a pubsub instance
# TODO: Start after delay
asyncio.ensure_future(self.heartbeat())
def add_peer(self, peer_id: ID, protocol_id: TProtocol) -> None:
@ -127,8 +130,7 @@ class GossipSub(IPubsubRouter):
# instance in multistream-select, but it is not the protocol that gossipsub supports.
# In this case, probably we registered gossipsub to a wrong `protocol_id`
# in multistream-select, or wrong versions.
# TODO: Better handling
raise Exception(f"protocol is not supported: protocol_id={protocol_id}")
raise Exception(f"Unreachable: Protocol={protocol_id} is not supported.")
self.peers_to_protocol[peer_id] = protocol_id
def remove_peer(self, peer_id: ID) -> None:
@ -144,6 +146,15 @@ class GossipSub(IPubsubRouter):
elif peer_id in self.peers_floodsub:
self.peers_floodsub.remove(peer_id)
for topic in self.mesh:
if peer_id in self.mesh[topic]:
# Delete the entry if no other peers left
self.mesh[topic].remove(peer_id)
for topic in self.fanout:
if peer_id in self.fanout[topic]:
# Delete the entry if no other peers left
self.fanout[topic].remove(peer_id)
self.peers_to_protocol.pop(peer_id, None)
async def handle_rpc(self, rpc: rpc_pb2.RPC, sender_peer_id: ID) -> None:
@ -204,42 +215,46 @@ class GossipSub(IPubsubRouter):
:param origin: peer id of the peer the message originate from.
:return: a generator of the peer ids who we send data to.
"""
send_to: Set[ID] = set()
send_to: List[ID] = []
for topic in topic_ids:
if topic not in self.pubsub.peer_topics:
continue
# floodsub peers
for peer_id in self.pubsub.peer_topics[topic]:
# FIXME: `gossipsub.peers_floodsub` can be changed to `gossipsub.peers` in go.
# This will improve the efficiency when searching for a peer's protocol id.
if peer_id in self.peers_floodsub:
send_to.add(peer_id)
# FIXME: `gossipsub.peers_floodsub` can be changed to `gossipsub.peers` in go.
# This will improve the efficiency when searching for a peer's protocol id.
floodsub_peers: List[ID] = [
peer_id
for peer_id in self.pubsub.peer_topics[topic]
if peer_id in self.peers_floodsub
]
# gossipsub peers
in_topic_gossipsub_peers: List[ID] = None
# TODO: Do we need to check `topic in self.pubsub.my_topics`?
gossipsub_peers: List[ID] = []
if topic in self.mesh:
in_topic_gossipsub_peers = self.mesh[topic]
gossipsub_peers = self.mesh[topic]
else:
# TODO(robzajac): Is topic DEFINITELY supposed to be in fanout if we are not
# subscribed?
# I assume there could be short periods between heartbeats where topic may not
# be but we should check that this path gets hit appropriately
if (topic not in self.fanout) or (len(self.fanout[topic]) == 0):
# If no peers in fanout, choose some peers from gossipsub peers in topic.
self.fanout[topic] = self._get_in_topic_gossipsub_peers_from_minus(
topic, self.degree, []
)
in_topic_gossipsub_peers = self.fanout[topic]
for peer_id in in_topic_gossipsub_peers:
send_to.add(peer_id)
# When we publish to a topic that we have not subscribe to, we randomly pick
# `self.degree` number of peers who have subscribed to the topic and add them
# as our `fanout` peers.
topic_in_fanout: bool = topic in self.fanout
fanout_peers: List[ID] = self.fanout[topic] if topic_in_fanout else []
fanout_size = len(fanout_peers)
if not topic_in_fanout or (
topic_in_fanout and fanout_size < self.degree
):
if topic in self.pubsub.peer_topics:
# Combine fanout peers with selected peers
fanout_peers += self._get_in_topic_gossipsub_peers_from_minus(
topic, self.degree - fanout_size, fanout_peers
)
self.fanout[topic] = fanout_peers
gossipsub_peers = fanout_peers
send_to.extend(floodsub_peers + gossipsub_peers)
# Excludes `msg_forwarder` and `origin`
yield from send_to.difference([msg_forwarder, origin])
yield from set(send_to).difference([msg_forwarder, origin])
async def join(self, topic: str) -> None:
# Note: the comments here are the near-exact algorithm description from the spec
"""
Join notifies the router that we want to receive and forward messages
in a topic. It is invoked after the subscription announcement.
@ -269,9 +284,8 @@ class GossipSub(IPubsubRouter):
# Add fanout peers to mesh and notifies them with a GRAFT(topic) control message.
for peer in fanout_peers:
if peer not in self.mesh[topic]:
self.mesh[topic].append(peer)
await self.emit_graft(topic, peer)
self.mesh[topic].append(peer)
await self.emit_graft(topic, peer)
self.fanout.pop(topic, None)
@ -292,7 +306,75 @@ class GossipSub(IPubsubRouter):
await self.emit_prune(topic, peer)
# Forget mesh[topic]
del self.mesh[topic]
self.mesh.pop(topic, None)
async def _emit_control_msgs(
self,
peers_to_graft: Dict[ID, List[str]],
peers_to_prune: Dict[ID, List[str]],
peers_to_gossip: Dict[ID, Dict[str, List[str]]],
) -> None:
graft_msgs: List[rpc_pb2.ControlGraft] = []
prune_msgs: List[rpc_pb2.ControlPrune] = []
ihave_msgs: List[rpc_pb2.ControlIHave] = []
# Starting with GRAFT messages
for peer, topics in peers_to_graft.items():
for topic in topics:
graft_msg: rpc_pb2.ControlGraft = rpc_pb2.ControlGraft(topicID=topic)
graft_msgs.append(graft_msg)
# If there are also PRUNE messages to send to this peer
if peer in peers_to_prune:
for topic in peers_to_prune[peer]:
prune_msg: rpc_pb2.ControlPrune = rpc_pb2.ControlPrune(
topicID=topic
)
prune_msgs.append(prune_msg)
del peers_to_prune[peer]
# If there are also IHAVE messages to send to this peer
if peer in peers_to_gossip:
for topic in peers_to_gossip[peer]:
ihave_msg: rpc_pb2.ControlIHave = rpc_pb2.ControlIHave(
messageIDs=peers_to_gossip[peer][topic], topicID=topic
)
ihave_msgs.append(ihave_msg)
del peers_to_gossip[peer]
control_msg = self.pack_control_msgs(ihave_msgs, graft_msgs, prune_msgs)
await self.emit_control_message(control_msg, peer)
# Next with PRUNE messages
for peer, topics in peers_to_prune.items():
prune_msgs = []
for topic in topics:
prune_msg = rpc_pb2.ControlPrune(topicID=topic)
prune_msgs.append(prune_msg)
# If there are also IHAVE messages to send to this peer
if peer in peers_to_gossip:
ihave_msgs = []
for topic in peers_to_gossip[peer]:
ihave_msg = rpc_pb2.ControlIHave(
messageIDs=peers_to_gossip[peer][topic], topicID=topic
)
ihave_msgs.append(ihave_msg)
del peers_to_gossip[peer]
control_msg = self.pack_control_msgs(ihave_msgs, None, prune_msgs)
await self.emit_control_message(control_msg, peer)
# Fianlly IHAVE messages
for peer in peers_to_gossip:
ihave_msgs = []
for topic in peers_to_gossip[peer]:
ihave_msg = rpc_pb2.ControlIHave(
messageIDs=peers_to_gossip[peer][topic], topicID=topic
)
ihave_msgs.append(ihave_msg)
control_msg = self.pack_control_msgs(ihave_msgs, None, None)
await self.emit_control_message(control_msg, peer)
# Heartbeat
async def heartbeat(self) -> None:
@ -302,16 +384,29 @@ class GossipSub(IPubsubRouter):
Note: the heartbeats are called with awaits because each heartbeat depends on the
state changes in the preceding heartbeat
"""
# Start after a delay. Ref: https://github.com/libp2p/go-libp2p-pubsub/blob/01b9825fbee1848751d90a8469e3f5f43bac8466/gossipsub.go#L410 # Noqa: E501
await asyncio.sleep(self.heartbeat_initial_delay)
while True:
# Maintain mesh and keep track of which peers to send GRAFT or PRUNE to
peers_to_graft, peers_to_prune = self.mesh_heartbeat()
# Maintain fanout
self.fanout_heartbeat()
# Get the peers to send IHAVE to
peers_to_gossip = self.gossip_heartbeat()
# Pack GRAFT, PRUNE and IHAVE for the same peer into one control message and send it
await self._emit_control_msgs(
peers_to_graft, peers_to_prune, peers_to_gossip
)
await self.mesh_heartbeat()
await self.fanout_heartbeat()
await self.gossip_heartbeat()
self.mcache.shift()
await asyncio.sleep(self.heartbeat_interval)
async def mesh_heartbeat(self) -> None:
# Note: the comments here are the exact pseudocode from the spec
def mesh_heartbeat(
self
) -> Tuple[DefaultDict[ID, List[str]], DefaultDict[ID, List[str]]]:
peers_to_graft: DefaultDict[ID, List[str]] = defaultdict(list)
peers_to_prune: DefaultDict[ID, List[str]] = defaultdict(list)
for topic in self.mesh:
# Skip if no peers have subscribed to the topic
if topic not in self.pubsub.peer_topics:
@ -324,15 +419,12 @@ class GossipSub(IPubsubRouter):
topic, self.degree - num_mesh_peers_in_topic, self.mesh[topic]
)
fanout_peers_not_in_mesh: List[ID] = [
peer for peer in selected_peers if peer not in self.mesh[topic]
]
for peer in fanout_peers_not_in_mesh:
for peer in selected_peers:
# Add peer to mesh[topic]
self.mesh[topic].append(peer)
# Emit GRAFT(topic) control message to peer
await self.emit_graft(topic, peer)
peers_to_graft[peer].append(topic)
if num_mesh_peers_in_topic > self.degree_high:
# Select |mesh[topic]| - D peers from mesh[topic]
@ -344,18 +436,31 @@ class GossipSub(IPubsubRouter):
self.mesh[topic].remove(peer)
# Emit PRUNE(topic) control message to peer
await self.emit_prune(topic, peer)
peers_to_prune[peer].append(topic)
return peers_to_graft, peers_to_prune
async def fanout_heartbeat(self) -> None:
def fanout_heartbeat(self) -> None:
# Note: the comments here are the exact pseudocode from the spec
for topic in self.fanout:
# If time since last published > ttl
# Delete topic entry if it's not in `pubsub.peer_topics`
# or if it's time-since-last-published > ttl
# TODO: there's no way time_since_last_publish gets set anywhere yet
if self.time_since_last_publish[topic] > self.time_to_live:
if (
topic not in self.pubsub.peer_topics
or self.time_since_last_publish[topic] > self.time_to_live
):
# Remove topic from fanout
del self.fanout[topic]
del self.time_since_last_publish[topic]
else:
# Check if fanout peers are still in the topic and remove the ones that are not
# ref: https://github.com/libp2p/go-libp2p-pubsub/blob/01b9825fbee1848751d90a8469e3f5f43bac8466/gossipsub.go#L498-L504 # noqa: E501
in_topic_fanout_peers = [
peer
for peer in self.fanout[topic]
if peer in self.pubsub.peer_topics[topic]
]
self.fanout[topic] = in_topic_fanout_peers
num_fanout_peers_in_topic = len(self.fanout[topic])
# If |fanout[topic]| < D
@ -369,51 +474,37 @@ class GossipSub(IPubsubRouter):
# Add the peers to fanout[topic]
self.fanout[topic].extend(selected_peers)
async def gossip_heartbeat(self) -> None:
def gossip_heartbeat(self) -> DefaultDict[ID, Dict[str, List[str]]]:
peers_to_gossip: DefaultDict[ID, Dict[str, List[str]]] = defaultdict(dict)
for topic in self.mesh:
msg_ids = self.mcache.window(topic)
if msg_ids:
# TODO: Make more efficient, possibly using a generator?
# Get all pubsub peers in a topic and only add them if they are gossipsub peers too
if topic in self.pubsub.peer_topics:
# Select D peers from peers.gossipsub[topic]
peers_to_emit_ihave_to = self._get_in_topic_gossipsub_peers_from_minus(
topic, self.degree, []
topic, self.degree, self.mesh[topic]
)
msg_id_strs = [str(msg_id) for msg_id in msg_ids]
for peer in peers_to_emit_ihave_to:
# TODO: this line is a monster, can hopefully be simplified
if (
topic not in self.mesh or (peer not in self.mesh[topic])
) and (
topic not in self.fanout or (peer not in self.fanout[topic])
):
msg_id_strs = [str(msg_id) for msg_id in msg_ids]
await self.emit_ihave(topic, msg_id_strs, peer)
peers_to_gossip[peer][topic] = msg_id_strs
# TODO: Refactor and Dedup. This section is the roughly the same as the above.
# Do the same for fanout, for all topics not already hit in mesh
for topic in self.fanout:
if topic not in self.mesh:
msg_ids = self.mcache.window(topic)
if msg_ids:
# TODO: Make more efficient, possibly using a generator?
# Get all pubsub peers in topic and only add if they are gossipsub peers also
if topic in self.pubsub.peer_topics:
# Select D peers from peers.gossipsub[topic]
peers_to_emit_ihave_to = self._get_in_topic_gossipsub_peers_from_minus(
topic, self.degree, []
)
for peer in peers_to_emit_ihave_to:
if (
peer not in self.mesh[topic]
and peer not in self.fanout[topic]
):
msg_id_strs = [str(msg) for msg in msg_ids]
await self.emit_ihave(topic, msg_id_strs, peer)
self.mcache.shift()
msg_ids = self.mcache.window(topic)
if msg_ids:
# Get all pubsub peers in topic and only add if they are gossipsub peers also
if topic in self.pubsub.peer_topics:
# Select D peers from peers.gossipsub[topic]
peers_to_emit_ihave_to = self._get_in_topic_gossipsub_peers_from_minus(
topic, self.degree, self.fanout[topic]
)
msg_id_strs = [str(msg) for msg in msg_ids]
for peer in peers_to_emit_ihave_to:
peers_to_gossip[peer][topic] = msg_id_strs
return peers_to_gossip
@staticmethod
def select_from_minus(
@ -548,6 +639,21 @@ class GossipSub(IPubsubRouter):
# RPC emitters
def pack_control_msgs(
self,
ihave_msgs: List[rpc_pb2.ControlIHave],
graft_msgs: List[rpc_pb2.ControlGraft],
prune_msgs: List[rpc_pb2.ControlPrune],
) -> rpc_pb2.ControlMessage:
control_msg: rpc_pb2.ControlMessage = rpc_pb2.ControlMessage()
if ihave_msgs:
control_msg.ihave.extend(ihave_msgs)
if graft_msgs:
control_msg.graft.extend(graft_msgs)
if prune_msgs:
control_msg.prune.extend(prune_msgs)
return control_msg
async def emit_ihave(self, topic: str, msg_ids: Any, to_peer: ID) -> None:
"""Emit ihave message, sent to to_peer, for topic and msg_ids."""

13
libp2p/pubsub/pubsub.py
View File

@ -78,7 +78,6 @@ class Pubsub:
topic_validators: Dict[str, TopicValidator]
# TODO: Be sure it is increased atomically everytime.
counter: int # uint64
_tasks: List["asyncio.Future[Any]"]
@ -300,7 +299,6 @@ class Pubsub:
logger.debug("Fail to add new peer %s: stream closed", peer_id)
del self.peers[peer_id]
return
# TODO: Check EOF of this stream.
# TODO: Check if the peer in black list.
try:
self.router.add_peer(peer_id, stream.get_protocol())
@ -318,6 +316,7 @@ class Pubsub:
for topic in self.peer_topics:
if peer_id in self.peer_topics[topic]:
# Delete the entry if no other peers left
self.peer_topics[topic].remove(peer_id)
self.router.remove_peer(peer_id)
@ -325,12 +324,9 @@ class Pubsub:
logger.debug("removed dead peer %s", peer_id)
async def handle_peer_queue(self) -> None:
"""
Continuously read from peer queue and each time a new peer is found,
open a stream to the peer using a supported pubsub protocol
TODO: Handle failure for when the peer does not support any of the
pubsub protocols we support
"""
"""Continuously read from peer queue and each time a new peer is found,
open a stream to the peer using a supported pubsub protocol pubsub
protocols we support."""
while True:
peer_id: ID = await self.peer_queue.get()
# Add Peer
@ -364,6 +360,7 @@ class Pubsub:
else:
if sub_message.topicid in self.peer_topics:
if origin_id in self.peer_topics[sub_message.topicid]:
# Delete the entry if no other peers left
self.peer_topics[sub_message.topicid].remove(origin_id)
# FIXME(mhchia): Change the function name?

1
libp2p/tools/constants.py
View File

@ -24,6 +24,7 @@ class GossipsubParams(NamedTuple):
time_to_live: int = 30
gossip_window: int = 3
gossip_history: int = 5
heartbeat_initial_delay: float = 0.1
heartbeat_interval: float = 0.5

1
libp2p/tools/factories.py
View File

@ -142,6 +142,7 @@ class GossipsubFactory(factory.Factory):
time_to_live = GOSSIPSUB_PARAMS.time_to_live
gossip_window = GOSSIPSUB_PARAMS.gossip_window
gossip_history = GOSSIPSUB_PARAMS.gossip_history
heartbeat_initial_delay = GOSSIPSUB_PARAMS.heartbeat_initial_delay
heartbeat_interval = GOSSIPSUB_PARAMS.heartbeat_interval