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

240 lines
7.3 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 std/[hashes, options, sequtils, strutils, tables]
import chronos, chronicles, nimcrypto/sha2, metrics
import rpc/[messages, message, protobuf],
timedcache,
../../peerid,
../../peerinfo,
../../stream/connection,
../../crypto/crypto,
../../protobuf/minprotobuf,
../../utility
logScope:
topics = "pubsubpeer"
declareCounter(libp2p_pubsub_sent_messages, "number of messages sent", labels = ["id", "topic"])
declareCounter(libp2p_pubsub_received_messages, "number of messages received", labels = ["id", "topic"])
declareCounter(libp2p_pubsub_skipped_received_messages, "number of received skipped messages", labels = ["id"])
declareCounter(libp2p_pubsub_skipped_sent_messages, "number of sent skipped messages", labels = ["id"])
const
DefaultReadTimeout* = 1.minutes
DefaultSendTimeout* = 10.seconds
type
PubSubObserver* = ref object
onRecv*: proc(peer: PubSubPeer; msgs: var RPCMsg) {.gcsafe, raises: [Defect].}
onSend*: proc(peer: PubSubPeer; msgs: var RPCMsg) {.gcsafe, raises: [Defect].}
PubSubPeer* = ref object of RootObj
proto*: string # the protocol that this peer joined from
sendConn: Connection
peerInfo*: PeerInfo
handler*: RPCHandler
sentRpcCache: TimedCache[string] # cache for already sent messages
recvdRpcCache: TimedCache[string] # cache for already received messages
onConnect*: AsyncEvent
observers*: ref seq[PubSubObserver] # ref as in smart_ptr
RPCHandler* = proc(peer: PubSubPeer, msg: seq[RPCMsg]): Future[void] {.gcsafe.}
func hash*(p: PubSubPeer): Hash =
# int is either 32/64, so intptr basically, pubsubpeer is a ref
cast[pointer](p).hash
proc id*(p: PubSubPeer): string = p.peerInfo.id
proc connected*(p: PubSubPeer): bool =
not(isNil(p.sendConn))
proc `conn=`*(p: PubSubPeer, conn: Connection) =
if not(isNil(conn)):
trace "attaching send connection for peer", peer = p.id
p.sendConn = conn
p.onConnect.fire()
proc conn*(p: PubSubPeer): Connection =
p.sendConn
proc recvObservers(p: PubSubPeer, msg: var RPCMsg) =
# trigger hooks
if not(isNil(p.observers)) and p.observers[].len > 0:
for obs in p.observers[]:
if not(isNil(obs)): # TODO: should never be nil, but...
obs.onRecv(p, msg)
proc sendObservers(p: PubSubPeer, msg: var RPCMsg) =
# trigger hooks
if not(isNil(p.observers)) and p.observers[].len > 0:
for obs in p.observers[]:
if not(isNil(obs)): # TODO: should never be nil, but...
obs.onSend(p, msg)
proc handle*(p: PubSubPeer, conn: Connection) {.async.} =
logScope:
peer = p.id
debug "starting pubsub read loop for peer", closed = conn.closed
try:
try:
while not conn.atEof:
trace "waiting for data", closed = conn.closed
let data = await conn.readLp(64 * 1024).wait(DefaultReadTimeout)
let digest = $(sha256.digest(data))
trace "read data from peer", data = data.shortLog
if digest in p.recvdRpcCache:
libp2p_pubsub_skipped_received_messages.inc(labelValues = [p.id])
trace "message already received, skipping"
continue
var rmsg = decodeRpcMsg(data)
if rmsg.isErr():
notice "failed to decode msg from peer"
break
var msg = rmsg.get()
trace "decoded msg from peer", msg = msg.shortLog
# trigger hooks
p.recvObservers(msg)
for m in msg.messages:
for t in m.topicIDs:
# metrics
libp2p_pubsub_received_messages.inc(labelValues = [p.id, t])
await p.handler(p, @[msg])
p.recvdRpcCache.put(digest)
finally:
debug "exiting pubsub peer read loop"
await conn.close()
except CancelledError as exc:
raise exc
except CatchableError as exc:
trace "Exception occurred in PubSubPeer.handle", exc = exc.msg
raise exc
proc send*(
p: PubSubPeer,
msg: RPCMsg,
timeout: Duration = DefaultSendTimeout) {.async.} =
logScope:
peer = p.id
msg = shortLog(msg)
trace "sending msg to peer"
# trigger send hooks
var mm = msg # hooks can modify the message
p.sendObservers(mm)
let encoded = encodeRpcMsg(mm)
if encoded.len <= 0:
info "empty message, skipping"
return
logScope:
encoded = shortLog(encoded)
let digest = $(sha256.digest(encoded))
if digest in p.sentRpcCache:
trace "message already sent to peer, skipping"
libp2p_pubsub_skipped_sent_messages.inc(labelValues = [p.id])
return
proc sendToRemote() {.async.} =
logScope:
peer = p.id
msg = shortLog(msg)
trace "about to send message"
if not p.onConnect.isSet:
await p.onConnect.wait()
if p.connected: # this can happen if the remote disconnected
trace "sending encoded msgs to peer"
await p.sendConn.writeLp(encoded)
p.sentRpcCache.put(digest)
trace "sent pubsub message to remote"
for x in mm.messages:
for t in x.topicIDs:
# metrics
libp2p_pubsub_sent_messages.inc(labelValues = [p.id, t])
let sendFut = sendToRemote()
try:
await sendFut.wait(timeout)
except CatchableError as exc:
trace "unable to send to remote", exc = exc.msg
if not sendFut.finished:
sendFut.cancel()
if not(isNil(p.sendConn)):
await p.sendConn.close()
p.sendConn = nil
p.onConnect.clear()
raise exc
proc sendSubOpts*(p: PubSubPeer, topics: seq[string], subscribe: bool) {.async.} =
trace "sending subscriptions", peer = p.id, subscribe, topicIDs = topics
try:
await p.send(RPCMsg(
subscriptions: topics.mapIt(SubOpts(subscribe: subscribe, topic: it))),
# the long timeout is mostly for cases where
# the connection is flaky at the beggingin
timeout = 3.minutes)
except CancelledError as exc:
raise exc
except CatchableError as exc:
trace "exception sending subscriptions", exc = exc.msg
proc sendGraft*(p: PubSubPeer, topics: seq[string]) {.async.} =
trace "sending graft to peer", peer = p.id, topicIDs = topics
try:
await p.send(RPCMsg(control: some(
ControlMessage(graft: topics.mapIt(ControlGraft(topicID: it))))),
timeout = 1.minutes)
except CancelledError as exc:
raise exc
except CatchableError as exc:
trace "exception sending grafts", exc = exc.msg
proc sendPrune*(p: PubSubPeer, topics: seq[string]) {.async.} =
trace "sending prune to peer", peer = p.id, topicIDs = topics
try:
await p.send(RPCMsg(control: some(
ControlMessage(prune: topics.mapIt(ControlPrune(topicID: it))))),
timeout = 1.minutes)
except CancelledError as exc:
raise exc
except CatchableError as exc:
trace "exception sending prunes", exc = exc.msg
proc `$`*(p: PubSubPeer): string =
p.id
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()