nim-libp2p/libp2p/protocols/pubsub/pubsubpeer.nim

129 lines
4.4 KiB
Nim

## Nim-LibP2P
## Copyright (c) 2019 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import options, hashes, strutils, tables, hashes
import chronos, chronicles
import rpc/[messages, message, protobuf],
timedcache,
../../peer,
../../peerinfo,
../../connection,
../../stream/lpstream,
../../crypto/crypto,
../../protobuf/minprotobuf
logScope:
topic = "PubSubPeer"
type
PubSubPeer* = ref object of RootObj
proto: string # the protocol that this peer joined from
sendConn: Connection
peerInfo*: PeerInfo
handler*: RPCHandler
topics*: seq[string]
sentRpcCache: TimedCache[string] # cache for already sent messages
recvdRpcCache: TimedCache[string] # cache for already received messages
refs*: int # refcount of the connections this peer is handling
onConnect: AsyncEvent
RPCHandler* = proc(peer: PubSubPeer, msg: seq[RPCMsg]): Future[void] {.gcsafe.}
proc id*(p: PubSubPeer): string = p.peerInfo.id
proc isConnected*(p: PubSubPeer): bool =
(not isNil(p.sendConn))
proc `conn=`*(p: PubSubPeer, conn: Connection) =
trace "attaching send connection for peer", peer = p.id
p.sendConn = conn
p.onConnect.fire()
proc handle*(p: PubSubPeer, conn: Connection) {.async.} =
trace "handling pubsub rpc", peer = p.id, closed = conn.closed
try:
while not conn.closed:
trace "waiting for data", peer = p.id, closed = conn.closed
let data = await conn.readLp()
let hexData = data.toHex()
trace "read data from peer", peer = p.id, data = hexData
if $hexData.hash in p.recvdRpcCache:
trace "message already received, skipping", peer = p.id
continue
let msg = decodeRpcMsg(data)
trace "decoded msg from peer", peer = p.id, msg = $msg
await p.handler(p, @[msg])
p.recvdRpcCache.put($hexData.hash)
except CatchableError as exc:
error "exception occurred in PubSubPeer.handle", exc = exc.msg
finally:
trace "exiting pubsub peer read loop", peer = p.id
if not conn.closed():
await conn.close()
proc send*(p: PubSubPeer, msgs: seq[RPCMsg]) {.async.} =
try:
for m in msgs:
trace "sending msgs to peer", toPeer = p.id
let encoded = encodeRpcMsg(m)
let encodedHex = encoded.buffer.toHex()
if encoded.buffer.len <= 0:
trace "empty message, skipping", peer = p.id
return
if $encodedHex.hash in p.sentRpcCache:
trace "message already sent to peer, skipping", peer = p.id
continue
proc sendToRemote() {.async.} =
trace "sending encoded msgs to peer", peer = p.id, encoded = encodedHex
await p.sendConn.writeLp(encoded.buffer)
p.sentRpcCache.put($encodedHex.hash)
# if no connection has been set,
# queue messages untill a connection
# becomes available
if p.isConnected:
await sendToRemote()
return
p.onConnect.wait().addCallback do (udata: pointer):
asyncCheck sendToRemote()
trace "enqueued message to send at a later time", peer = p.id,
encoded = encodedHex
except CatchableError as exc:
trace "exception occurred in PubSubPeer.send", exc = exc.msg
proc sendMsg*(p: PubSubPeer,
peerId: PeerID,
topic: string,
data: seq[byte]): Future[void] {.gcsafe.} =
p.send(@[RPCMsg(messages: @[newMessage(p.peerInfo, data, topic)])])
proc sendGraft*(p: PubSubPeer, topics: seq[string]) {.async.} =
for topic in topics:
trace "sending graft msg to peer", peer = p.id, topicID = topic
await p.send(@[RPCMsg(control: some(ControlMessage(graft: @[ControlGraft(topicID: topic)])))])
proc sendPrune*(p: PubSubPeer, topics: seq[string]) {.async.} =
for topic in topics:
trace "sending prune msg to peer", peer = p.id, topicID = topic
await p.send(@[RPCMsg(control: some(ControlMessage(prune: @[ControlPrune(topicID: topic)])))])
proc newPubSubPeer*(peerInfo: PeerInfo,
proto: string): PubSubPeer =
new result
result.proto = proto
result.peerInfo = peerInfo
result.sentRpcCache = newTimedCache[string](2.minutes)
result.recvdRpcCache = newTimedCache[string](2.minutes)
result.onConnect = newAsyncEvent()