Suppress beacon sync unless potential actions (#2765)

* Update comments & logs

* Do not start beacon sync unless there is possibly something to do

why:
  It would continue polling without having any effect other than
  logging. Now it will not start unless there is RPC available
  or there was a previously interrupted sync to be resumed.

nimbus/nimbus_desc.nim

@@ -63,8 +63,8 @@ proc stop*(nimbus: NimbusNode, conf: NimbusConf) {.async, gcsafe.} =
  await nimbus.networkLoop.cancelAndWait()
  if nimbus.peerManager.isNil.not:
  await nimbus.peerManager.stop()
- #if nimbus.snapSyncRef.isNil.not:
- # nimbus.snapSyncRef.stop()
+ if nimbus.beaconSyncRef.isNil.not:
+ nimbus.beaconSyncRef.stop()
  if nimbus.metricsServer.isNil.not:
  await nimbus.metricsServer.stop()
 

nimbus/nimbus_execution_client.nim

@@ -110,17 +110,13 @@ proc setupP2P(nimbus: NimbusNode, conf: NimbusConf,
  nimbus.ethNode.peerPool,
  nimbus.chainRef,
  nimbus.txPool)
- #of ProtocolFlag.Snap:
- # nimbus.ethNode.addSnapHandlerCapability(
- # nimbus.ethNode.peerPool,
- # nimbus.chainRef)
  # Cannot do without minimal `eth` capability
  if ProtocolFlag.Eth notin protocols:
  nimbus.ethNode.addEthHandlerCapability(
  nimbus.ethNode.peerPool,
  nimbus.chainRef)
 
- # Always start syncer -- will throttle itself unless needed
+ # Always initialise beacon syncer
  nimbus.beaconSyncRef = BeaconSyncRef.init(
  nimbus.ethNode, nimbus.chainRef, conf.maxPeers, conf.beaconChunkSize)
 
@@ -225,7 +221,11 @@ proc run(nimbus: NimbusNode, conf: NimbusConf) =
  setupRpc(nimbus, conf, com, protocols)
 
  if conf.maxPeers > 0:
- nimbus.beaconSyncRef.start
+ # Not starting syncer if there is definitely no way to run it. This
+ # avoids polling (i.e. waiting for instructions) and some logging.
+ let resumeOnly = not conf.engineApiServerEnabled()
+ if not nimbus.beaconSyncRef.start(resumeOnly):
+ nimbus.beaconSyncRef = BeaconSyncRef(nil)
 
  if nimbus.state == NimbusState.Starting:
  # it might have been set to "Stopping" with Ctrl+C

nimbus/sync/beacon.nim

@@ -14,7 +14,7 @@ import
  pkg/[chronicles, chronos, eth/p2p, results],
  pkg/stew/[interval_set, sorted_set],
  ../core/chain,
- ./beacon/[worker, worker_desc],
+ ./beacon/[worker, worker_desc, worker/db],
  "."/[sync_desc, sync_sched, protocol]
 
 logScope:
@@ -62,16 +62,20 @@ proc init*(
  var desc = T()
  desc.initSync(ethNode, maxPeers)
  desc.ctx.pool.nBodiesBatch = chunkSize
- # Initalise for `persistBlocks()`
  desc.ctx.pool.chain = chain
  desc
 
-proc start*(ctx: BeaconSyncRef) =
- ## Beacon Sync always begin with stop mode
- doAssert ctx.startSync() # Initialize subsystems
-
-proc stop*(ctx: BeaconSyncRef) =
- ctx.stopSync()
+proc start*(desc: BeaconSyncRef; resumeOnly = false): bool =
+ ## Start beacon sync. If `resumeOnly` is set `true` the syncer will only
+ ## start up if it can resume work, e.g. after being previously interrupted.
+ if resumeOnly:
+ desc.ctx.dbLoadSyncStateLayout()
+ if not desc.ctx.layout.headLocked:
+ return false
+ desc.startSync()
+
+proc stop*(desc: BeaconSyncRef) =
+ desc.stopSync()
 
 # ------------------------------------------------------------------------------
 # End

nimbus/sync/beacon/worker/start_stop.nim

@@ -98,7 +98,7 @@ proc setupDatabase*(ctx: BeaconCtxRef) =
  # Load initial state from database if there is any
  ctx.dbLoadSyncStateLayout()
 
- # Set blocks batch import value for `persistBlocks()`
+ # Set blocks batch import value for block import
  if ctx.pool.nBodiesBatch < nFetchBodiesRequest:
  if ctx.pool.nBodiesBatch == 0:
  ctx.pool.nBodiesBatch = nFetchBodiesBatchDefault

nimbus/sync/beacon/worker/start_stop/ticker.nim

@@ -18,7 +18,7 @@ import
  ../helpers
 
 logScope:
- topics = "ticker"
+ topics = "beacon ticker"
 
 type
  TickerStatsUpdater* = proc: TickerStats {.gcsafe, raises: [].}
@@ -108,10 +108,10 @@ proc tickerLogger(t: TickerRef) {.gcsafe.} =
  t.visited = now
 
  if data.stored == data.base:
- info "Sync state", up, peers,
+ debug "Sync state", up, peers,
  B, L, C, D, F, H, T, hS, hU, bS, bU, rrg, mem
  else:
- info "Sync state", up, peers,
+ debug "Sync state", up, peers,
  S=data.stored.bnStr,
  B, L, C, D, F, H, T, hS, hU, bS, bU, rrg, mem
 

nimbus/sync/beacon/worker_desc.nim

@@ -130,7 +130,7 @@ type
  blkSync*: BlocksImportSync ## For importing/executing blocks
  nextUpdate*: Moment ## For updating metrics
 
- # Blocks import/execution settings for running `persistBlocks()` with
+ # Blocks import/execution settings for importing with
  # `nBodiesBatch` blocks in each round (minimum value is
  # `nFetchBodiesRequest`.)
  chain*: ForkedChainRef ## Database