Highlight execution client for optimistically synced node (#4266)

...such that the user knows where to look

beacon_chain/nimbus_beacon_node.nim

@@ -1200,7 +1200,7 @@ proc onSlotEnd(node: BeaconNode, slot: Slot) {.async.} =
 
   # Update upcoming actions - we do this every slot in case a reorg happens
   let head = node.dag.head
-  if node.isSynced(head):
+  if node.isSynced(head) == SyncStatus.synced:
     withState(node.dag.headState):
       if node.consensusManager[].actionTracker.needsUpdate(
           forkyState, slot.epoch + 1):

beacon_chain/rpc/rest_utils.nim

@@ -36,7 +36,7 @@ func match(data: openArray[char], charset: set[char]): int =
 proc getSyncedHead*(node: BeaconNode, slot: Slot): Result[BlockRef, cstring] =
   let head = node.dag.head
 
-  if slot > head.slot and not node.isSynced(head):
+  if slot > head.slot and node.isSynced(head) != SyncStatus.synced:
     return err("Requesting way ahead of the current head")
 
   ok(head)

beacon_chain/rpc/rest_validator_api.nim

@@ -265,7 +265,7 @@ proc installValidatorApiHandlers*(router: var RestRouter, node: BeaconNode) =
       return RestApiResponse.jsonResponseWOpt(res, optimistic)
     elif qSyncPeriod > headSyncPeriod:
       # The requested epoch may still be too far in the future.
-      if not(node.isSynced(node.dag.head)):
+      if node.isSynced(node.dag.head) != SyncStatus.synced:
         return RestApiResponse.jsonError(Http503, BeaconNodeInSyncError)
       else:
         return RestApiResponse.jsonError(Http400, EpochFromFutureError)
@@ -566,7 +566,7 @@ proc installValidatorApiHandlers*(router: var RestRouter, node: BeaconNode) =
                                            InvalidSubscriptionRequestValueError,
                                            $dres.error())
         dres.get()
-    if not(node.isSynced(node.dag.head)):
+    if node.isSynced(node.dag.head) != SyncStatus.synced:
       return RestApiResponse.jsonError(Http503, BeaconNodeInSyncError)
 
     let

beacon_chain/validator_client/fallback_service.nim

@@ -207,7 +207,7 @@ proc checkSync(vc: ValidatorClientRef,
                head_slot = syncInfo.head_slot, is_opimistic = optimistic
           RestBeaconNodeStatus.Online
         else:
-          warn "Beacon node is optimistically synced only",
+          warn "Execution client not in sync (beacon node optimistically synced)",
                sync_distance = syncInfo.sync_distance,
                head_slot = syncInfo.head_slot, is_opimistic = optimistic
           RestBeaconNodeStatus.NotSynced

beacon_chain/validators/validator_duties.nim

@@ -91,6 +91,11 @@ logScope: topics = "beacval"
 type
   ForkedBlockResult* = Result[ForkedBeaconBlock, string]
 
+  SyncStatus* {.pure.} = enum
+    synced
+    unsynced
+    optimistic
+
 proc findValidator*(validators: auto, pubkey: ValidatorPubKey): Opt[ValidatorIndex] =
   let idx = validators.findIt(it.pubkey == pubkey)
   if idx == -1:
@@ -153,7 +158,7 @@ proc getAttachedValidator(node: BeaconNode,
       idx, head = shortLog(node.dag.head)
     nil
 
-proc isSynced*(node: BeaconNode, head: BlockRef): bool =
+proc isSynced*(node: BeaconNode, head: BlockRef): SyncStatus =
   ## TODO This function is here as a placeholder for some better heurestics to
   ##      determine if we're in sync and should be producing blocks and
   ##      attestations. Generally, the problem is that slot time keeps advancing
@@ -176,9 +181,12 @@ proc isSynced*(node: BeaconNode, head: BlockRef): bool =
   #      else to do it
   if  wallSlot.afterGenesis and
       head.slot + node.config.syncHorizon < wallSlot.slot:
-    false
+    SyncStatus.unsynced
   else:
-    not node.dag.is_optimistic(head.root)
+    if node.dag.is_optimistic(head.root):
+      SyncStatus.optimistic
+    else:
+      SyncStatus.synced
 
 proc handleLightClientUpdates*(node: BeaconNode, slot: Slot) {.async.} =
   static: doAssert lightClientFinalityUpdateSlotOffset ==
@@ -1353,8 +1361,9 @@ proc handleValidatorDuties*(node: BeaconNode, lastSlot, slot: Slot) {.async.} =
   # The dag head might be updated by sync while we're working due to the
   # await calls, thus we use a local variable to keep the logic straight here
   var head = node.dag.head
-  if not node.isSynced(head):
-    info "Syncing in progress; skipping validator duties for now",
+  case node.isSynced(head)
+  of SyncStatus.unsynced:
+    info "Beacon node not in sync; skipping validator duties for now",
       slot, headSlot = head.slot
 
     # Rewards will be growing though, as we sync..
@@ -1362,6 +1371,17 @@ proc handleValidatorDuties*(node: BeaconNode, lastSlot, slot: Slot) {.async.} =
 
     return
 
+  of SyncStatus.optimistic:
+    info "Execution client not in sync; skipping validator duties for now",
+      slot, headSlot = head.slot
+
+    # Rewards will be growing though, as we sync..
+    updateValidatorMetrics(node)
+
+    return
+  of SyncStatus.synced:
+    discard # keep going
+
   var curSlot = lastSlot + 1
 
   # If broadcastStartEpoch is 0, it hasn't had time to initialize yet, which
@@ -1495,7 +1515,7 @@ proc registerDuties*(node: BeaconNode, wallSlot: Slot) {.async.} =
   ## Register upcoming duties of attached validators with the duty tracker
 
   if node.attachedValidators[].count() == 0 or
-      not node.isSynced(node.dag.head):
+      node.isSynced(node.dag.head) != SyncStatus.synced:
     # Nothing to do because we have no validator attached
     return