580 lines
19 KiB
Nim
580 lines
19 KiB
Nim
## Nim-LibP2P
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## Copyright (c) 2019 Status Research & Development GmbH
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## Licensed under either of
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## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
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## * MIT license ([LICENSE-MIT](LICENSE-MIT))
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## at your option.
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## This file may not be copied, modified, or distributed except according to
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## those terms.
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import tables, sets, options, sequtils, random
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import chronos, chronicles, metrics
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import pubsub,
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floodsub,
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pubsubpeer,
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mcache,
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timedcache,
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rpc/[messages, message],
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../protocol,
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../../peerinfo,
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../../stream/connection,
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../../peerid,
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../../errors,
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../../utility
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logScope:
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topics = "gossipsub"
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const GossipSubCodec* = "/meshsub/1.0.0"
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# overlay parameters
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const GossipSubD* = 6
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const GossipSubDlo* = 4
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const GossipSubDhi* = 12
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# gossip parameters
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const GossipSubHistoryLength* = 5
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const GossipSubHistoryGossip* = 3
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# heartbeat interval
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const GossipSubHeartbeatInitialDelay* = 100.millis
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const GossipSubHeartbeatInterval* = 1.seconds
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# fanout ttl
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const GossipSubFanoutTTL* = 1.minutes
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type
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GossipSub* = ref object of FloodSub
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mesh*: Table[string, HashSet[string]] # meshes - topic to peer
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fanout*: Table[string, HashSet[string]] # fanout - topic to peer
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gossipsub*: Table[string, HashSet[string]] # topic to peer map of all gossipsub peers
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lastFanoutPubSub*: Table[string, Moment] # last publish time for fanout topics
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gossip*: Table[string, seq[ControlIHave]] # pending gossip
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control*: Table[string, ControlMessage] # pending control messages
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mcache*: MCache # messages cache
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heartbeatFut: Future[void] # cancellation future for heartbeat interval
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heartbeatRunning: bool
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heartbeatLock: AsyncLock # heartbeat lock to prevent two consecutive concurrent heartbeats
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declareGauge(libp2p_gossipsub_peers_per_topic_mesh,
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"gossipsub peers per topic in mesh",
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labels = ["topic"])
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declareGauge(libp2p_gossipsub_peers_per_topic_fanout,
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"gossipsub peers per topic in fanout",
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labels = ["topic"])
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declareGauge(libp2p_gossipsub_peers_per_topic_gossipsub,
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"gossipsub peers per topic in gossipsub",
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labels = ["topic"])
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method init*(g: GossipSub) =
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proc handler(conn: Connection, proto: string) {.async.} =
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## main protocol handler that gets triggered on every
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## connection for a protocol string
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## e.g. ``/floodsub/1.0.0``, etc...
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##
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await g.handleConn(conn, proto)
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g.handler = handler
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g.codec = GossipSubCodec
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proc replenishFanout(g: GossipSub, topic: string) =
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## get fanout peers for a topic
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trace "about to replenish fanout"
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if topic notin g.fanout:
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g.fanout[topic] = initHashSet[string]()
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if g.fanout.getOrDefault(topic).len < GossipSubDLo:
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trace "replenishing fanout", peers = g.fanout.getOrDefault(topic).len
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if topic in toSeq(g.gossipsub.keys):
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for p in g.gossipsub.getOrDefault(topic):
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if not g.fanout[topic].containsOrIncl(p):
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if g.fanout.getOrDefault(topic).len == GossipSubD:
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break
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libp2p_gossipsub_peers_per_topic_fanout
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.set(g.fanout.getOrDefault(topic).len.int64,
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labelValues = [topic])
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trace "fanout replenished with peers", peers = g.fanout.getOrDefault(topic).len
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template moveToMeshHelper(g: GossipSub,
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topic: string,
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table: Table[string, HashSet[string]]) =
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## move peers from `table` into `mesh`
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##
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var peerIds = toSeq(table.getOrDefault(topic))
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logScope:
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topic = topic
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meshPeers = g.mesh.getOrDefault(topic).len
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peers = peerIds.len
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shuffle(peerIds)
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for id in peerIds:
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if g.mesh.getOrDefault(topic).len > GossipSubD:
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break
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trace "gathering peers for mesh"
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if topic notin table:
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continue
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trace "getting peers", topic,
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peers = peerIds.len
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table[topic].excl(id) # always exclude
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if id in g.mesh[topic]:
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continue # we already have this peer in the mesh, try again
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if id in g.peers:
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let p = g.peers[id]
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if p.connected:
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# send a graft message to the peer
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await p.sendGraft(@[topic])
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g.mesh[topic].incl(id)
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trace "got peer", peer = id
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proc rebalanceMesh(g: GossipSub, topic: string) {.async.} =
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try:
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trace "about to rebalance mesh"
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# create a mesh topic that we're subscribing to
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if topic notin g.mesh:
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g.mesh[topic] = initHashSet[string]()
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if g.mesh.getOrDefault(topic).len < GossipSubDlo:
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trace "replenishing mesh", topic
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# replenish the mesh if we're below GossipSubDlo
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# move fanout nodes first
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g.moveToMeshHelper(topic, g.fanout)
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# move gossipsub nodes second
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g.moveToMeshHelper(topic, g.gossipsub)
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if g.mesh.getOrDefault(topic).len > GossipSubDhi:
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# prune peers if we've gone over
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var mesh = toSeq(g.mesh.getOrDefault(topic))
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shuffle(mesh)
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trace "about to prune mesh", mesh = mesh.len
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for id in mesh:
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if g.mesh.getOrDefault(topic).len <= GossipSubD:
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break
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trace "pruning peers", peers = g.mesh[topic].len
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let p = g.peers[id]
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# send a graft message to the peer
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await p.sendPrune(@[topic])
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g.mesh[topic].excl(id)
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if topic in g.gossipsub:
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g.gossipsub[topic].incl(id)
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libp2p_gossipsub_peers_per_topic_gossipsub
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.set(g.gossipsub.getOrDefault(topic).len.int64,
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labelValues = [topic])
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libp2p_gossipsub_peers_per_topic_fanout
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.set(g.fanout.getOrDefault(topic).len.int64,
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labelValues = [topic])
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libp2p_gossipsub_peers_per_topic_mesh
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.set(g.mesh.getOrDefault(topic).len.int64,
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labelValues = [topic])
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trace "mesh balanced, got peers", peers = g.mesh.getOrDefault(topic).len,
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topicId = topic
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except CancelledError as exc:
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raise exc
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except CatchableError as exc:
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warn "exception occurred re-balancing mesh", exc = exc.msg
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proc dropFanoutPeers(g: GossipSub) {.async.} =
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# drop peers that we haven't published to in
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# GossipSubFanoutTTL seconds
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var dropping = newSeq[string]()
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for topic, val in g.lastFanoutPubSub:
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if Moment.now > val:
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dropping.add(topic)
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g.fanout.del(topic)
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trace "dropping fanout topic", topic
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for topic in dropping:
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g.lastFanoutPubSub.del(topic)
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libp2p_gossipsub_peers_per_topic_fanout
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.set(g.fanout.getOrDefault(topic).len.int64, labelValues = [topic])
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proc getGossipPeers(g: GossipSub): Table[string, ControlMessage] {.gcsafe.} =
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## gossip iHave messages to peers
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##
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trace "getting gossip peers (iHave)"
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let topics = toHashSet(toSeq(g.mesh.keys)) + toHashSet(toSeq(g.fanout.keys))
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let controlMsg = ControlMessage()
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for topic in topics:
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var allPeers = toSeq(g.gossipsub.getOrDefault(topic))
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shuffle(allPeers)
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let mesh = g.mesh.getOrDefault(topic)
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let fanout = g.fanout.getOrDefault(topic)
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let gossipPeers = mesh + fanout
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let mids = g.mcache.window(topic)
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if mids.len <= 0:
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continue
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let ihave = ControlIHave(topicID: topic,
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messageIDs: toSeq(mids))
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if topic notin g.gossipsub:
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trace "topic not in gossip array, skipping", topicID = topic
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continue
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for id in allPeers:
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if result.len >= GossipSubD:
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trace "got gossip peers", peers = result.len
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break
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if allPeers.len == 0:
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trace "no peers for topic, skipping", topicID = topic
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break
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if id in gossipPeers:
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continue
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if id notin result:
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result[id] = controlMsg
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result[id].ihave.add(ihave)
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proc heartbeat(g: GossipSub) {.async.} =
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while g.heartbeatRunning:
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try:
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trace "running heartbeat"
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for t in toSeq(g.topics.keys):
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await g.rebalanceMesh(t)
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await g.dropFanoutPeers()
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# replenish known topics to the fanout
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for t in toSeq(g.fanout.keys):
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g.replenishFanout(t)
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let peers = g.getGossipPeers()
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var sent: seq[Future[void]]
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for peer in peers.keys:
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if peer in g.peers:
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sent &= g.peers[peer].send(@[RPCMsg(control: some(peers[peer]))])
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checkFutures(await allFinished(sent))
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g.mcache.shift() # shift the cache
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except CancelledError as exc:
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raise exc
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except CatchableError as exc:
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trace "exception ocurred in gossipsub heartbeat", exc = exc.msg
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await sleepAsync(5.seconds)
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method handleDisconnect*(g: GossipSub, peer: PubSubPeer) =
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## handle peer disconnects
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procCall FloodSub(g).handleDisconnect(peer)
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for t in toSeq(g.gossipsub.keys):
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if t in g.gossipsub:
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g.gossipsub[t].excl(peer.id)
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libp2p_gossipsub_peers_per_topic_gossipsub
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.set(g.gossipsub.getOrDefault(t).len.int64, labelValues = [t])
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for t in toSeq(g.mesh.keys):
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if t in g.mesh:
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g.mesh[t].excl(peer.id)
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libp2p_gossipsub_peers_per_topic_mesh
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.set(g.mesh[t].len.int64, labelValues = [t])
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for t in toSeq(g.fanout.keys):
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if t in g.fanout:
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g.fanout[t].excl(peer.id)
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libp2p_gossipsub_peers_per_topic_fanout
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.set(g.fanout[t].len.int64, labelValues = [t])
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method subscribePeer*(p: GossipSub,
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conn: Connection) =
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procCall PubSub(p).subscribePeer(conn)
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asyncCheck p.handleConn(conn, GossipSubCodec)
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method subscribeTopic*(g: GossipSub,
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topic: string,
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subscribe: bool,
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peerId: string) {.gcsafe, async.} =
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await procCall PubSub(g).subscribeTopic(topic, subscribe, peerId)
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if topic notin g.gossipsub:
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g.gossipsub[topic] = initHashSet[string]()
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if subscribe:
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trace "adding subscription for topic", peer = peerId, name = topic
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# subscribe remote peer to the topic
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g.gossipsub[topic].incl(peerId)
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else:
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trace "removing subscription for topic", peer = peerId, name = topic
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# unsubscribe remote peer from the topic
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g.gossipsub[topic].excl(peerId)
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if peerId in g.mesh.getOrDefault(topic):
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g.mesh[topic].excl(peerId)
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if peerId in g.fanout.getOrDefault(topic):
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g.fanout[topic].excl(peerId)
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libp2p_gossipsub_peers_per_topic_gossipsub
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.set(g.gossipsub[topic].len.int64, labelValues = [topic])
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trace "gossip peers", peers = g.gossipsub[topic].len, topic
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# also rebalance current topic if we are subbed to
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if topic in g.topics:
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await g.rebalanceMesh(topic)
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proc handleGraft(g: GossipSub,
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peer: PubSubPeer,
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grafts: seq[ControlGraft],
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respControl: var ControlMessage) =
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for graft in grafts:
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trace "processing graft message", peer = peer.id,
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topicID = graft.topicID
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if graft.topicID in g.topics:
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if g.mesh.len < GossipSubD:
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g.mesh[graft.topicID].incl(peer.id)
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else:
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g.gossipsub[graft.topicID].incl(peer.id)
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else:
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respControl.prune.add(ControlPrune(topicID: graft.topicID))
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libp2p_gossipsub_peers_per_topic_mesh
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.set(g.mesh[graft.topicID].len.int64, labelValues = [graft.topicID])
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libp2p_gossipsub_peers_per_topic_gossipsub
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.set(g.gossipsub[graft.topicID].len.int64, labelValues = [graft.topicID])
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proc handlePrune(g: GossipSub, peer: PubSubPeer, prunes: seq[ControlPrune]) =
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for prune in prunes:
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trace "processing prune message", peer = peer.id,
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topicID = prune.topicID
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if prune.topicID in g.mesh:
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g.mesh[prune.topicID].excl(peer.id)
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g.gossipsub[prune.topicID].incl(peer.id)
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libp2p_gossipsub_peers_per_topic_mesh
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.set(g.mesh[prune.topicID].len.int64, labelValues = [prune.topicID])
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proc handleIHave(g: GossipSub,
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peer: PubSubPeer,
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ihaves: seq[ControlIHave]): ControlIWant =
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for ihave in ihaves:
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trace "processing ihave message", peer = peer.id,
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topicID = ihave.topicID,
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msgs = ihave.messageIDs
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if ihave.topicID in g.mesh:
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for m in ihave.messageIDs:
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if m notin g.seen:
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result.messageIDs.add(m)
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proc handleIWant(g: GossipSub,
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peer: PubSubPeer,
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iwants: seq[ControlIWant]): seq[Message] =
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for iwant in iwants:
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for mid in iwant.messageIDs:
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trace "processing iwant message", peer = peer.id,
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messageID = mid
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let msg = g.mcache.get(mid)
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if msg.isSome:
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result.add(msg.get())
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method rpcHandler*(g: GossipSub,
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peer: PubSubPeer,
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rpcMsgs: seq[RPCMsg]) {.async.} =
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await procCall PubSub(g).rpcHandler(peer, rpcMsgs)
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for m in rpcMsgs: # for all RPC messages
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if m.messages.len > 0: # if there are any messages
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var toSendPeers: HashSet[string]
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for msg in m.messages: # for every message
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let msgId = g.msgIdProvider(msg)
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logScope: msgId
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if msgId in g.seen:
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trace "message already processed, skipping"
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continue
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trace "processing message"
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g.seen.put(msgId) # add the message to the seen cache
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if g.verifySignature and not msg.verify(peer.peerInfo):
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trace "dropping message due to failed signature verification"
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continue
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if not (await g.validate(msg)):
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trace "dropping message due to failed validation"
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continue
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# this shouldn't happen
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if g.peerInfo.peerId == msg.fromPeer:
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trace "skipping messages from self"
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continue
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for t in msg.topicIDs: # for every topic in the message
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if t in g.floodsub:
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toSendPeers.incl(g.floodsub[t]) # get all floodsub peers for topic
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if t in g.mesh:
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toSendPeers.incl(g.mesh[t]) # get all mesh peers for topic
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if t in g.topics: # if we're subscribed to the topic
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for h in g.topics[t].handler:
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trace "calling handler for message", topicId = t,
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localPeer = g.peerInfo.id,
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fromPeer = msg.fromPeer.pretty
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try:
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await h(t, msg.data) # trigger user provided handler
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except CatchableError as exc:
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trace "exception in message handler", exc = exc.msg
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# forward the message to all peers interested in it
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let (published, failed) = await g.sendHelper(toSendPeers, m.messages)
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for p in failed:
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let peer = g.peers.getOrDefault(p)
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if not isNil(peer):
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g.handleDisconnect(peer) # cleanup failed peers
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trace "forwared message to peers", peers = published.len
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var respControl: ControlMessage
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if m.control.isSome:
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var control: ControlMessage = m.control.get()
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let iWant: ControlIWant = g.handleIHave(peer, control.ihave)
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if iWant.messageIDs.len > 0:
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respControl.iwant.add(iWant)
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let messages: seq[Message] = g.handleIWant(peer, control.iwant)
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g.handleGraft(peer, control.graft, respControl)
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g.handlePrune(peer, control.prune)
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if respControl.graft.len > 0 or respControl.prune.len > 0 or
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respControl.ihave.len > 0 or respControl.iwant.len > 0:
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await peer.send(@[RPCMsg(control: some(respControl), messages: messages)])
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method subscribe*(g: GossipSub,
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topic: string,
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handler: TopicHandler) {.async.} =
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await procCall PubSub(g).subscribe(topic, handler)
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await g.rebalanceMesh(topic)
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method unsubscribe*(g: GossipSub,
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topics: seq[TopicPair]) {.async.} =
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await procCall PubSub(g).unsubscribe(topics)
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for pair in topics:
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let topic = pair.topic
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if topic in g.mesh:
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let peers = g.mesh.getOrDefault(topic)
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g.mesh.del(topic)
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for id in peers:
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let p = g.peers[id]
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await p.sendPrune(@[topic])
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method publish*(g: GossipSub,
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topic: string,
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data: seq[byte]): Future[int] {.async.} =
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# base returns always 0
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discard await procCall PubSub(g).publish(topic, data)
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trace "about to publish message on topic", name = topic,
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data = data.shortLog
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var peers: HashSet[string]
|
|
if topic.len <= 0: # data could be 0/empty
|
|
return 0
|
|
|
|
if topic in g.topics: # if we're subscribed use the mesh
|
|
peers = g.mesh.getOrDefault(topic)
|
|
else: # not subscribed, send to fanout peers
|
|
# try optimistically
|
|
peers = g.fanout.getOrDefault(topic)
|
|
if peers.len == 0:
|
|
# ok we had nothing.. let's try replenish inline
|
|
g.replenishFanout(topic)
|
|
peers = g.fanout.getOrDefault(topic)
|
|
|
|
let
|
|
msg = Message.init(g.peerInfo, data, topic, g.sign)
|
|
msgId = g.msgIdProvider(msg)
|
|
|
|
trace "created new message", msg
|
|
|
|
trace "publishing on topic", name = topic, peers = peers
|
|
if msgId notin g.mcache:
|
|
g.mcache.put(msgId, msg)
|
|
|
|
let (published, failed) = await g.sendHelper(peers, @[msg])
|
|
for p in failed:
|
|
let peer = g.peers.getOrDefault(p)
|
|
if not isNil(peer):
|
|
g.handleDisconnect(peer) # cleanup failed peers
|
|
|
|
if published.len > 0:
|
|
libp2p_pubsub_messages_published.inc(labelValues = [topic])
|
|
|
|
trace "published message to peers", peers = published.len,
|
|
msg = msg.shortLog()
|
|
return published.len
|
|
|
|
method start*(g: GossipSub) {.async.} =
|
|
trace "gossipsub start"
|
|
|
|
## start pubsub
|
|
## start long running/repeating procedures
|
|
|
|
# interlock start to to avoid overlapping to stops
|
|
await g.heartbeatLock.acquire()
|
|
|
|
# setup the heartbeat interval
|
|
g.heartbeatRunning = true
|
|
g.heartbeatFut = g.heartbeat()
|
|
|
|
g.heartbeatLock.release()
|
|
|
|
method stop*(g: GossipSub) {.async.} =
|
|
trace "gossipsub stop"
|
|
|
|
## stop pubsub
|
|
## stop long running tasks
|
|
|
|
await g.heartbeatLock.acquire()
|
|
|
|
# stop heartbeat interval
|
|
g.heartbeatRunning = false
|
|
if not g.heartbeatFut.finished:
|
|
trace "awaiting last heartbeat"
|
|
await g.heartbeatFut
|
|
trace "heartbeat stopped"
|
|
|
|
g.heartbeatLock.release()
|
|
|
|
method initPubSub*(g: GossipSub) =
|
|
procCall FloodSub(g).initPubSub()
|
|
|
|
randomize()
|
|
g.mcache = newMCache(GossipSubHistoryGossip, GossipSubHistoryLength)
|
|
g.mesh = initTable[string, HashSet[string]]() # meshes - topic to peer
|
|
g.fanout = initTable[string, HashSet[string]]() # fanout - topic to peer
|
|
g.gossipsub = initTable[string, HashSet[string]]()# topic to peer map of all gossipsub peers
|
|
g.lastFanoutPubSub = initTable[string, Moment]() # last publish time for fanout topics
|
|
g.gossip = initTable[string, seq[ControlIHave]]() # pending gossip
|
|
g.control = initTable[string, ControlMessage]() # pending control messages
|
|
g.heartbeatLock = newAsyncLock()
|