402 lines
12 KiB
Nim
402 lines
12 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 std/[tables, sequtils, sets]
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import chronos, chronicles, metrics
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import pubsubpeer,
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rpc/[message, messages],
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../../switch,
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../protocol,
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../../stream/connection,
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../../peerid,
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../../peerinfo,
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../../errors
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import metrics
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import stew/results
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export results
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export PubSubPeer
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export PubSubObserver
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export protocol
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logScope:
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topics = "pubsub"
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declareGauge(libp2p_pubsub_peers, "pubsub peer instances")
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declareGauge(libp2p_pubsub_topics, "pubsub subscribed topics")
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declareCounter(libp2p_pubsub_validation_success, "pubsub successfully validated messages")
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declareCounter(libp2p_pubsub_validation_failure, "pubsub failed validated messages")
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declareCounter(libp2p_pubsub_validation_ignore, "pubsub ignore validated messages")
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when defined(libp2p_expensive_metrics):
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declarePublicCounter(libp2p_pubsub_messages_published, "published messages", labels = ["topic"])
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type
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TopicHandler* = proc(topic: string,
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data: seq[byte]): Future[void] {.gcsafe.}
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ValidationResult* {.pure.} = enum
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Accept, Reject, Ignore
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ValidatorHandler* = proc(topic: string,
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message: Message): Future[ValidationResult] {.gcsafe, closure.}
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TopicPair* = tuple[topic: string, handler: TopicHandler]
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MsgIdProvider* =
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proc(m: Message): MessageID {.noSideEffect, raises: [Defect], nimcall, gcsafe.}
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Topic* = object
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# make this a variant type if one day we have different Params structs
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name*: string
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handler*: seq[TopicHandler]
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PubSub* = ref object of LPProtocol
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switch*: Switch # the switch used to dial/connect to peers
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peerInfo*: PeerInfo # this peer's info
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topics*: Table[string, Topic] # local topics
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peers*: Table[PeerID, PubSubPeer] ##\
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## Peers that we are interested to gossip with (but not necessarily
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## yet connected to)
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triggerSelf*: bool # trigger own local handler on publish
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verifySignature*: bool # enable signature verification
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sign*: bool # enable message signing
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validators*: Table[string, HashSet[ValidatorHandler]]
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observers: ref seq[PubSubObserver] # ref as in smart_ptr
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msgIdProvider*: MsgIdProvider # Turn message into message id (not nil)
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msgSeqno*: uint64
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anonymize*: bool # if we omit fromPeer and seqno from RPC messages we send
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method unsubscribePeer*(p: PubSub, peerId: PeerID) {.base.} =
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## handle peer disconnects
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##
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debug "unsubscribing pubsub peer", peerId
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p.peers.del(peerId)
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libp2p_pubsub_peers.set(p.peers.len.int64)
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proc send*(p: PubSub, peer: PubSubPeer, msg: RPCMsg) =
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## Attempt to send `msg` to remote peer
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##
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trace "sending pubsub message to peer", peer, msg = shortLog(msg)
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peer.send(msg, p.anonymize)
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proc broadcast*(
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p: PubSub,
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sendPeers: openArray[PubSubPeer],
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msg: RPCMsg) = # raises: [Defect]
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## Attempt to send `msg` to the given peers
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trace "broadcasting messages to peers",
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peers = sendPeers.len, msg = shortLog(msg)
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for peer in sendPeers:
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p.send(peer, msg)
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proc sendSubs*(p: PubSub,
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peer: PubSubPeer,
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topics: seq[string],
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subscribe: bool) =
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## send subscriptions to remote peer
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p.send(peer, RPCMsg.withSubs(topics, subscribe))
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method subscribeTopic*(p: PubSub,
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topic: string,
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subscribe: bool,
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peer: PubSubPeer) {.base.} =
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# called when remote peer subscribes to a topic
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discard
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method rpcHandler*(p: PubSub,
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peer: PubSubPeer,
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rpcMsg: RPCMsg) {.async, base.} =
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## handle rpc messages
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trace "processing RPC message", msg = rpcMsg.shortLog, peer
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for s in rpcMsg.subscriptions: # subscribe/unsubscribe the peer for each topic
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trace "about to subscribe to topic", topicId = s.topic, peer
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p.subscribeTopic(s.topic, s.subscribe, peer)
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method onNewPeer(p: PubSub, peer: PubSubPeer) {.base.} = discard
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method onPubSubPeerEvent*(p: PubSub, peer: PubsubPeer, event: PubsubPeerEvent) {.base, gcsafe.} =
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# Peer event is raised for the send connection in particular
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case event.kind
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of PubSubPeerEventKind.Connected:
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if p.topics.len > 0:
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p.sendSubs(peer, toSeq(p.topics.keys), true)
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of PubSubPeerEventKind.Disconnected:
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discard
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proc getOrCreatePeer*(
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p: PubSub,
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peer: PeerID,
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protos: seq[string]): PubSubPeer =
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if peer in p.peers:
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return p.peers[peer]
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proc getConn(): Future[Connection] =
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p.switch.dial(peer, protos)
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proc onEvent(peer: PubsubPeer, event: PubsubPeerEvent) {.gcsafe.} =
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p.onPubSubPeerEvent(peer, event)
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# create new pubsub peer
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let pubSubPeer = newPubSubPeer(peer, getConn, onEvent, protos[0])
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debug "created new pubsub peer", peer
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p.peers[peer] = pubSubPeer
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pubSubPeer.observers = p.observers
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onNewPeer(p, pubSubPeer)
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# metrics
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libp2p_pubsub_peers.set(p.peers.len.int64)
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pubsubPeer.connect()
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return pubSubPeer
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proc handleData*(p: PubSub, topic: string, data: seq[byte]): Future[void] {.async.} =
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if topic notin p.topics: return # Not subscribed
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for h in p.topics[topic].handler:
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trace "triggering handler", topicID = topic
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try:
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await h(topic, data)
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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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# Handlers should never raise exceptions
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warn "Error in topic handler", msg = exc.msg
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method handleConn*(p: PubSub,
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conn: Connection,
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proto: string) {.base, async.} =
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## handle incoming connections
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##
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## this proc will:
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## 1) register a new PubSubPeer for the connection
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## 2) register a handler with the peer;
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## this handler gets called on every rpc message
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## that the peer receives
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## 3) ask the peer to subscribe us to every topic
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## that we're interested in
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##
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if isNil(conn.peerInfo):
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trace "no valid PeerId for peer"
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await conn.close()
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return
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proc handler(peer: PubSubPeer, msg: RPCMsg): Future[void] =
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# call pubsub rpc handler
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p.rpcHandler(peer, msg)
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let peer = p.getOrCreatePeer(conn.peerInfo.peerId, @[proto])
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try:
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peer.handler = handler
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await peer.handle(conn) # spawn peer read loop
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trace "pubsub peer handler ended", conn
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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 pubsub handle", exc = exc.msg, conn
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finally:
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await conn.closeWithEOF()
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method subscribePeer*(p: PubSub, peer: PeerID) {.base.} =
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## subscribe to remote peer to receive/send pubsub
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## messages
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##
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let peer = p.getOrCreatePeer(peer, p.codecs)
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peer.outbound = true # flag as outbound
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method unsubscribe*(p: PubSub,
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topics: seq[TopicPair]) {.base, async.} =
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## unsubscribe from a list of ``topic`` strings
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for t in topics:
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let
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handler = t.handler
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ttopic = t.topic
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closureScope:
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p.topics.withValue(ttopic, topic):
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topic[].handler.keepIf(proc (x: auto): bool = x != handler)
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if topic[].handler.len == 0:
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# make sure we delete the topic if
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# no more handlers are left
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p.topics.del(ttopic)
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libp2p_pubsub_topics.set(p.topics.len.int64)
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proc unsubscribe*(p: PubSub,
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topic: string,
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handler: TopicHandler): Future[void] =
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## unsubscribe from a ``topic`` string
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##
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p.unsubscribe(@[(topic, handler)])
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method unsubscribeAll*(p: PubSub, topic: string) {.base, async.} =
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p.topics.del(topic)
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libp2p_pubsub_topics.set(p.topics.len.int64)
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method subscribe*(p: PubSub,
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topic: string,
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handler: TopicHandler) {.base, async.} =
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## subscribe to a topic
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##
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## ``topic`` - a string topic to subscribe to
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##
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## ``handler`` - is a user provided proc
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## that will be triggered
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## on every received message
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##
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if topic notin p.topics:
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trace "subscribing to topic", name = topic
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p.topics[topic] = Topic(name: topic)
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p.topics[topic].handler.add(handler)
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for _, peer in p.peers:
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p.sendSubs(peer, @[topic], true)
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# metrics
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libp2p_pubsub_topics.set(p.topics.len.int64)
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method publish*(p: PubSub,
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topic: string,
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data: seq[byte]): Future[int] {.base, async.} =
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## publish to a ``topic``
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## The return value is the number of neighbours that we attempted to send the
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## message to, excluding self. Note that this is an optimistic number of
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## attempts - the number of peers that actually receive the message might
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## be lower.
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if p.triggerSelf:
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await handleData(p, topic, data)
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return 0
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method initPubSub*(p: PubSub) {.base.} =
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## perform pubsub initialization
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p.observers = new(seq[PubSubObserver])
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if p.msgIdProvider == nil:
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p.msgIdProvider = defaultMsgIdProvider
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method start*(p: PubSub) {.async, base.} =
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## start pubsub
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discard
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method stop*(p: PubSub) {.async, base.} =
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## stopt pubsub
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discard
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method addValidator*(p: PubSub,
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topic: varargs[string],
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hook: ValidatorHandler) {.base.} =
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for t in topic:
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if t notin p.validators:
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p.validators[t] = initHashSet[ValidatorHandler]()
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trace "adding validator for topic", topicId = t
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p.validators[t].incl(hook)
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method removeValidator*(p: PubSub,
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topic: varargs[string],
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hook: ValidatorHandler) {.base.} =
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for t in topic:
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if t in p.validators:
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p.validators[t].excl(hook)
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method validate*(p: PubSub, message: Message): Future[ValidationResult] {.async, base.} =
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var pending: seq[Future[ValidationResult]]
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trace "about to validate message"
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for topic in message.topicIDs:
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trace "looking for validators on topic", topicID = topic,
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registered = toSeq(p.validators.keys)
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if topic in p.validators:
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trace "running validators for topic", topicID = topic
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# TODO: add timeout to validator
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pending.add(p.validators[topic].mapIt(it(topic, message)))
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result = ValidationResult.Accept
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let futs = await allFinished(pending)
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for fut in futs:
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if fut.failed:
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result = ValidationResult.Reject
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break
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let res = fut.read()
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if res != ValidationResult.Accept:
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result = res
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break
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case result
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of ValidationResult.Accept:
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libp2p_pubsub_validation_success.inc()
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of ValidationResult.Reject:
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libp2p_pubsub_validation_failure.inc()
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of ValidationResult.Ignore:
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libp2p_pubsub_validation_ignore.inc()
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proc init*[PubParams: object | bool](
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P: typedesc[PubSub],
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switch: Switch,
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triggerSelf: bool = false,
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anonymize: bool = false,
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verifySignature: bool = true,
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sign: bool = true,
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msgIdProvider: MsgIdProvider = defaultMsgIdProvider,
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parameters: PubParams = false): P =
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let pubsub =
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when PubParams is bool:
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P(switch: switch,
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peerInfo: switch.peerInfo,
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triggerSelf: triggerSelf,
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anonymize: anonymize,
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verifySignature: verifySignature,
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sign: sign,
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peers: initTable[PeerID, PubSubPeer](),
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topics: initTable[string, Topic](),
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msgIdProvider: msgIdProvider)
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else:
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P(switch: switch,
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peerInfo: switch.peerInfo,
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triggerSelf: triggerSelf,
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anonymize: anonymize,
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verifySignature: verifySignature,
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sign: sign,
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peers: initTable[PeerID, PubSubPeer](),
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topics: initTable[string, Topic](),
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msgIdProvider: msgIdProvider,
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parameters: parameters)
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proc peerEventHandler(peerId: PeerID, event: PeerEvent) {.async.} =
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if event == PeerEvent.Joined:
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pubsub.subscribePeer(peerId)
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else:
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pubsub.unsubscribePeer(peerId)
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switch.addPeerEventHandler(peerEventHandler, PeerEvent.Joined)
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switch.addPeerEventHandler(peerEventHandler, PeerEvent.Left)
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pubsub.initPubSub()
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return pubsub
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proc addObserver*(p: PubSub; observer: PubSubObserver) = p.observers[] &= observer
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proc removeObserver*(p: PubSub; observer: PubSubObserver) =
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let idx = p.observers[].find(observer)
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if idx != -1:
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p.observers[].del(idx)
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