feat: running periodicaly peer exchange if discv5 is disabled (#3150)

tests/test_waku_keepalive.nim

@@ -44,7 +44,7 @@ suite "Waku Keepalive":
 
     await node1.connectToNodes(@[node2.switch.peerInfo.toRemotePeerInfo()])
 
-    node1.startKeepalive()
+    node1.startKeepalive(2.seconds)
 
     check:
       (await completionFut.withTimeout(5.seconds)) == true

waku/factory/node_factory.nim

@@ -422,7 +422,11 @@ proc startNode*(
       desiredOutDegree = node.wakuRelay.parameters.d.uint64()
     (await node.fetchPeerExchangePeers(desiredOutDegree)).isOkOr:
       error "error while fetching peers from peer exchange", error = error
-      quit(QuitFailure)
+
+  # Use px to periodically get peers if discv5 is disabled, as discv5 nodes have their own
+  # periodic loop to find peers and px returned peers actually come from discv5
+  if conf.peerExchange and not conf.discv5Discovery:
+    node.startPeerExchangeLoop()
 
   # Start keepalive, if enabled
   if conf.keepAlive:

waku/node/waku_node.nim

@@ -1146,7 +1146,7 @@ proc mountPeerExchange*(
     error "failed to mount wakuPeerExchange", error = getCurrentExceptionMsg()
 
 proc fetchPeerExchangePeers*(
-    node: Wakunode, amount: uint64
+    node: Wakunode, amount = DefaultPXNumPeersReq
 ): Future[Result[int, PeerExchangeResponseStatus]] {.async: (raises: []).} =
   if node.wakuPeerExchange.isNil():
     error "could not get peers from px, waku peer-exchange is nil"
@@ -1175,6 +1175,20 @@ proc fetchPeerExchangePeers*(
       error = pxPeersRes.error
     return err(pxPeersRes.error)
 
+proc peerExchangeLoop(node: WakuNode) {.async.} =
+  while true:
+    await sleepAsync(1.minutes)
+    if not node.started:
+      continue
+    (await node.fetchPeerExchangePeers()).isOkOr:
+      warn "Cannot fetch peers from peer exchange", cause = error
+
+proc startPeerExchangeLoop*(node: WakuNode) =
+  if node.wakuPeerExchange.isNil():
+    error "startPeerExchangeLoop: Peer Exchange is not mounted"
+    return
+  node.wakuPeerExchange.pxLoopHandle = node.peerExchangeLoop()
+
 # TODO: Move to application module (e.g., wakunode2.nim)
 proc setPeerExchangePeer*(
     node: WakuNode, peer: RemotePeerInfo | MultiAddress | string
@@ -1217,7 +1231,11 @@ proc mountLibp2pPing*(node: WakuNode) {.async: (raises: []).} =
 
 # TODO: Move this logic to PeerManager
 proc keepaliveLoop(node: WakuNode, keepalive: chronos.Duration) {.async.} =
-  while node.started:
+  while true:
+    await sleepAsync(keepalive)
+    if not node.started:
+      continue
+
     # Keep connected peers alive while running
     # Each node is responsible of keeping its outgoing connections alive
     trace "Running keepalive"
@@ -1235,14 +1253,11 @@ proc keepaliveLoop(node: WakuNode, keepalive: chronos.Duration) {.async.} =
       except CatchableError as exc:
         waku_node_errors.inc(labelValues = ["keep_alive_failure"])
 
-    await sleepAsync(keepalive)
+# 2 minutes default - 20% of the default chronosstream timeout duration
+proc startKeepalive*(node: WakuNode, keepalive = 2.minutes) =
+  info "starting keepalive", keepalive = keepalive
 
-proc startKeepalive*(node: WakuNode) =
-  let defaultKeepalive = 2.minutes # 20% of the default chronosstream timeout duration
-
-  info "starting keepalive", keepalive = defaultKeepalive
-
-  asyncSpawn node.keepaliveLoop(defaultKeepalive)
+  asyncSpawn node.keepaliveLoop(keepalive)
 
 proc mountRendezvous*(node: WakuNode) {.async: (raises: []).} =
   info "mounting rendezvous discovery protocol"
@@ -1372,6 +1387,9 @@ proc stop*(node: WakuNode) {.async.} =
   if not node.wakuStoreResume.isNil():
     await node.wakuStoreResume.stopWait()
 
+  if not node.wakuPeerExchange.isNil() and not node.wakuPeerExchange.pxLoopHandle.isNil():
+    await node.wakuPeerExchange.pxLoopHandle.cancelAndWait()
+
   node.started = false
 
 proc isReady*(node: WakuNode): Future[bool] {.async: (raises: [Exception]).} =

waku/waku_peer_exchange/protocol.nim

@@ -57,6 +57,7 @@ type
     cluster*: Option[uint16]
       # todo: next step: ring buffer; future: implement cache satisfying https://rfc.vac.dev/spec/34/
     requestRateLimiter*: RequestRateLimiter
+    pxLoopHandle*: Future[void]
 
 proc request*(
     wpx: WakuPeerExchange, numPeers = DefaultPXNumPeersReq, conn: Connection