don't wait until after the first slot to enable gossip

beacon_chain/nimbus_beacon_node.nim

@@ -485,6 +485,57 @@ proc removeMessageHandlers(node: BeaconNode): Future[void] =
 
   allFutures(unsubscriptions)
 
+proc updateGossipStatus(node: BeaconNode, slot: Slot) {.async.} =
+  # Syncing tends to be ~1 block/s, and allow for an epoch of time for libp2p
+  # subscribing to spin up. The faster the sync, the more wallSlot - headSlot
+  # lead time is required
+  const
+    TOPIC_SUBSCRIBE_THRESHOLD_SLOTS = 64
+    HYSTERESIS_BUFFER = 16
+
+  let
+    syncQueueLen = node.syncManager.syncQueueLen
+    topicSubscriptionEnabled = node.getTopicSubscriptionEnabled()
+  if
+      # Don't enable if already enabled; to avoid race conditions requires care,
+      # but isn't crucial, as this condition spuriously fail, but the next time,
+      # should properly succeed.
+      not topicSubscriptionEnabled and
+      # SyncManager forward sync by default runs until maxHeadAge slots, or one
+      # epoch range is achieved. This particular condition has a couple caveats
+      # including that under certain conditions, debtsCount appears to push len
+      # (here, syncQueueLen) to underflow-like values; and even when exactly at
+      # the expected walltime slot the queue isn't necessarily empty. Therefore
+      # TOPIC_SUBSCRIBE_THRESHOLD_SLOTS is not exactly the number of slots that
+      # are left. Furthermore, even when 0 peers are being used, this won't get
+      # to 0 slots in syncQueueLen, but that's a vacuous condition given that a
+      # networking interaction cannot happen under such circumstances.
+      syncQueueLen < TOPIC_SUBSCRIBE_THRESHOLD_SLOTS:
+    # When node.cycleAttestationSubnets() is enabled more properly, integrate
+    # this into the node.cycleAttestationSubnets() call.
+    debug "Enabling topic subscriptions",
+      wallSlot = slot,
+      headSlot = node.chainDag.head.slot,
+      syncQueueLen
+
+    await node.addMessageHandlers()
+    doAssert node.getTopicSubscriptionEnabled()
+  elif
+      topicSubscriptionEnabled and
+      syncQueueLen > TOPIC_SUBSCRIBE_THRESHOLD_SLOTS + HYSTERESIS_BUFFER and
+      # Filter out underflow from debtsCount; plausible queue lengths can't
+      # exceed wallslot, with safety margin.
+      syncQueueLen < 2 * slot.uint64:
+    debug "Disabling topic subscriptions",
+      wallSlot = slot,
+      headSlot = node.chainDag.head.slot,
+      syncQueueLen
+    await node.removeMessageHandlers()
+
+  # Subscription or unsubscription might have occurred; recheck
+  if slot.isEpoch and node.getTopicSubscriptionEnabled:
+    node.cycleAttestationSubnets(slot)
+
 proc onSlotStart(node: BeaconNode, lastSlot, scheduledSlot: Slot) {.async.} =
   ## Called at the beginning of a slot - usually every slot, but sometimes might
   ## skip a few in case we're running late.
@@ -598,55 +649,7 @@ proc onSlotStart(node: BeaconNode, lastSlot, scheduledSlot: Slot) {.async.} =
     finalizedHead = shortLog(node.chainDag.finalizedHead.blck),
     finalizedEpoch = shortLog(node.chainDag.finalizedHead.blck.slot.compute_epoch_at_slot())
 
-  # Syncing tends to be ~1 block/s, and allow for an epoch of time for libp2p
-  # subscribing to spin up. The faster the sync, the more wallSlot - headSlot
-  # lead time is required
-  const
-    TOPIC_SUBSCRIBE_THRESHOLD_SLOTS = 64
-    HYSTERESIS_BUFFER = 16
-
-  let
-    syncQueueLen = node.syncManager.syncQueueLen
-    topicSubscriptionEnabled = node.getTopicSubscriptionEnabled()
-  if
-      # Don't enable if already enabled; to avoid race conditions requires care,
-      # but isn't crucial, as this condition spuriously fail, but the next time,
-      # should properly succeed.
-      not topicSubscriptionEnabled and
-      # SyncManager forward sync by default runs until maxHeadAge slots, or one
-      # epoch range is achieved. This particular condition has a couple caveats
-      # including that under certain conditions, debtsCount appears to push len
-      # (here, syncQueueLen) to underflow-like values; and even when exactly at
-      # the expected walltime slot the queue isn't necessarily empty. Therefore
-      # TOPIC_SUBSCRIBE_THRESHOLD_SLOTS is not exactly the number of slots that
-      # are left. Furthermore, even when 0 peers are being used, this won't get
-      # to 0 slots in syncQueueLen, but that's a vacuous condition given that a
-      # networking interaction cannot happen under such circumstances.
-      syncQueueLen < TOPIC_SUBSCRIBE_THRESHOLD_SLOTS:
-    # When node.cycleAttestationSubnets() is enabled more properly, integrate
-    # this into the node.cycleAttestationSubnets() call.
-    debug "Enabling topic subscriptions",
-      wallSlot = slot,
-      headSlot = node.chainDag.head.slot,
-      syncQueueLen
-
-    await node.addMessageHandlers()
-    doAssert node.getTopicSubscriptionEnabled()
-  elif
-      topicSubscriptionEnabled and
-      syncQueueLen > TOPIC_SUBSCRIBE_THRESHOLD_SLOTS + HYSTERESIS_BUFFER and
-      # Filter out underflow from debtsCount; plausible queue lengths can't
-      # exceed wallslot, with safety margin.
-      syncQueueLen < 2 * slot.uint64:
-    debug "Disabling topic subscriptions",
-      wallSlot = slot,
-      headSlot = node.chainDag.head.slot,
-      syncQueueLen
-    await node.removeMessageHandlers()
-
-  # Subscription or unsubscription might have occurred; recheck
-  if slot.isEpoch and node.getTopicSubscriptionEnabled:
-    node.cycleAttestationSubnets(slot)
+  await node.updateGossipStatus(slot)
 
   when declared(GC_fullCollect):
     # The slots in the beacon node work as frames in a game: we want to make
@@ -814,6 +817,9 @@ proc run*(node: BeaconNode) =
     node.requestManager.start()
     node.startSyncManager()
 
+    waitFor node.addMessageHandlers()
+    doAssert node.getTopicSubscriptionEnabled()
+
   ## Ctrl+C handling
   proc controlCHandler() {.noconv.} =
     when defined(windows):