nimbus-eth2/beacon_chain/validators/validator_duties.nim

714 lines
29 KiB
Nim

# beacon_chain
# Copyright (c) 2018-2021 Status Research & Development GmbH
# Licensed and distributed under either of
# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.
{.push raises: [Defect].}
import
# Standard library
std/[os, osproc, sequtils, streams, tables],
# Nimble packages
stew/[assign2, objects],
chronos, metrics,
chronicles,
json_serialization/std/[options, sets, net], serialization/errors,
eth/db/kvstore,
eth/keys, eth/p2p/discoveryv5/[protocol, enr],
# Local modules
../spec/[
datatypes, digest, crypto, helpers, network, signatures, state_transition],
../conf, ../beacon_clock,
../consensus_object_pools/[
spec_cache, blockchain_dag, block_clearance,
attestation_pool, exit_pool],
../eth1/eth1_monitor,
../networking/eth2_network,
".."/[beacon_node_common, beacon_node_types, version],
../ssz, ../ssz/sszdump, ../sync/sync_manager,
./slashing_protection, ./attestation_aggregation,
./validator_pool, ./keystore_management,
../gossip_processing/consensus_manager
# Metrics for tracking attestation and beacon block loss
const delayBuckets = [-Inf, -4.0, -2.0, -1.0, -0.5, -0.1, -0.05,
0.05, 0.1, 0.5, 1.0, 2.0, 4.0, 8.0, Inf]
declareCounter beacon_attestations_sent,
"Number of beacon chain attestations sent by this peer"
declareHistogram beacon_attestation_sent_delay,
"Time(s) between slot start and attestation sent moment",
buckets = delayBuckets
declareCounter beacon_blocks_proposed,
"Number of beacon chain blocks sent by this peer"
declareGauge(attached_validator_balance,
"Validator balance at slot end of the first 64 validators, in Gwei",
labels = ["pubkey"])
declarePublicGauge(attached_validator_balance_total,
"Validator balance of all attached validators, in Gwei")
logScope: topics = "beacval"
proc findValidator(validators: auto, pubKey: ValidatorPubKey):
Option[ValidatorIndex] =
let idx = validators.asSeq.findIt(it.pubKey == pubKey)
if idx == -1:
# We allow adding a validator even if its key is not in the state registry:
# it might be that the deposit for this validator has not yet been processed
notice "Validator deposit not yet processed, monitoring", pubKey
none(ValidatorIndex)
else:
some(idx.ValidatorIndex)
proc addLocalValidator(node: BeaconNode,
stateData: StateData,
privKey: ValidatorPrivKey) =
let pubKey = privKey.toPubKey()
node.attachedValidators[].addLocalValidator(
pubKey, privKey,
findValidator(getStateField(stateData, validators), pubKey))
proc addLocalValidators*(node: BeaconNode) =
for validatorKey in node.config.validatorKeys:
node.addLocalValidator node.chainDag.headState, validatorKey
proc addRemoteValidators*(node: BeaconNode) {.raises: [Defect, OSError, IOError].} =
# load all the validators from the child process - loop until `end`
var line = newStringOfCap(120).TaintedString
while line != "end" and running(node.vcProcess):
if node.vcProcess.outputStream.readLine(line) and line != "end":
let
key = ValidatorPubKey.fromHex(line).get()
index = findValidator(
getStateField(node.chainDag.headState, validators), key)
let v = AttachedValidator(pubKey: key,
index: index,
kind: ValidatorKind.remote,
connection: ValidatorConnection(
inStream: node.vcProcess.inputStream,
outStream: node.vcProcess.outputStream,
pubKeyStr: $key))
node.attachedValidators[].addRemoteValidator(key, v)
proc getAttachedValidator*(node: BeaconNode,
pubkey: ValidatorPubKey): AttachedValidator =
node.attachedValidators[].getValidator(pubkey)
proc getAttachedValidator*(node: BeaconNode,
state_validators: auto,
idx: ValidatorIndex): AttachedValidator =
if idx < state_validators.len.ValidatorIndex:
let validator = node.getAttachedValidator(state_validators[idx].pubkey)
if validator != nil and validator.index != some(idx.ValidatorIndex):
# Update index, in case the validator was activated!
notice "Validator activated", pubkey = validator.pubkey, index = idx
validator.index = some(idx.ValidatorIndex)
validator
else:
warn "Validator index out of bounds",
idx, validators = state_validators.len
nil
proc getAttachedValidator*(node: BeaconNode,
epochRef: EpochRef,
idx: ValidatorIndex): AttachedValidator =
if idx < epochRef.validator_keys.len.ValidatorIndex:
let validator = node.getAttachedValidator(epochRef.validator_keys[idx])
if validator != nil and validator.index != some(idx.ValidatorIndex):
# Update index, in case the validator was activated!
notice "Validator activated", pubkey = validator.pubkey, index = idx
validator.index = some(idx.ValidatorIndex)
validator
else:
warn "Validator index out of bounds",
idx, epoch = epochRef.epoch, validators = epochRef.validator_keys.len
nil
proc isSynced*(node: BeaconNode, head: BlockRef): bool =
## 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
## even when there are no blocks being produced, so there's no way to
## distinguish validators geniunely going missing from the node not being
## well connected (during a network split or an internet outage for
## example). It would generally be correct to simply keep running as if
## we were the only legit node left alive, but then we run into issues:
## with enough many empty slots, the validator pool is emptied leading
## to empty committees and lots of empty slot processing that will be
## thrown away as soon as we're synced again.
let
# The slot we should be at, according to the clock
beaconTime = node.beaconClock.now()
wallSlot = beaconTime.toSlot()
# TODO: MaxEmptySlotCount should likely involve the weak subjectivity period.
# TODO if everyone follows this logic, the network will not recover from a
# halt: nobody will be producing blocks because everone expects someone
# else to do it
if wallSlot.afterGenesis and head.slot + MaxEmptySlotCount < wallSlot.slot:
false
else:
true
proc sendAttestation*(
node: BeaconNode, attestation: Attestation,
subnet_id: SubnetId, checkSignature: bool): Future[bool] {.async.} =
# Validate attestation before sending it via gossip - validation will also
# register the attestation with the attestation pool. Notably, although
# libp2p calls the data handler for any subscription on the subnet
# topic, it does not perform validation.
let ok = await node.processor.attestationValidator(
attestation, subnet_id, checkSignature)
return case ok
of ValidationResult.Accept:
node.network.broadcast(
getAttestationTopic(node.forkDigest, subnet_id), attestation)
beacon_attestations_sent.inc()
true
else:
notice "Produced attestation failed validation",
attestation = shortLog(attestation),
result = $ok
false
proc sendVoluntaryExit*(node: BeaconNode, exit: SignedVoluntaryExit) =
node.network.broadcast(getVoluntaryExitsTopic(node.forkDigest), exit)
proc sendAttesterSlashing*(node: BeaconNode, slashing: AttesterSlashing) =
node.network.broadcast(getAttesterSlashingsTopic(node.forkDigest),
slashing)
proc sendProposerSlashing*(node: BeaconNode, slashing: ProposerSlashing) =
node.network.broadcast(getProposerSlashingsTopic(node.forkDigest),
slashing)
proc sendAttestation*(node: BeaconNode, attestation: Attestation): Future[bool] =
# For the validator API, which doesn't supply the subnet id.
let attestationBlck =
node.chainDag.getRef(attestation.data.beacon_block_root)
if attestationBlck.isNil:
debug "Attempt to send attestation without corresponding block"
return
let
epochRef = node.chainDag.getEpochRef(
attestationBlck, attestation.data.target.epoch)
subnet_id = compute_subnet_for_attestation(
get_committee_count_per_slot(epochRef), attestation.data.slot,
attestation.data.index.CommitteeIndex)
node.sendAttestation(attestation, subnet_id, checkSignature = true)
proc createAndSendAttestation(node: BeaconNode,
fork: Fork,
genesis_validators_root: Eth2Digest,
validator: AttachedValidator,
attestationData: AttestationData,
committeeLen: int,
indexInCommittee: int,
subnet_id: SubnetId) {.async.} =
try:
var
attestation = await validator.produceAndSignAttestation(
attestationData, committeeLen, indexInCommittee, fork,
genesis_validators_root)
let ok = await node.sendAttestation(
attestation, subnet_id, checkSignature = false)
if not ok: # Logged in sendAttestation
return
let sent = node.beaconClock.now()
if node.config.dumpEnabled:
dump(node.config.dumpDirOutgoing, attestation.data, validator.pubKey)
let wallTime = node.beaconClock.now()
let deadline = attestationData.slot.toBeaconTime() +
seconds(int(SECONDS_PER_SLOT div 3))
let (delayStr, delaySecs) =
if wallTime < deadline:
("-" & $(deadline - wallTime), -toFloatSeconds(deadline - wallTime))
else:
($(wallTime - deadline), toFloatSeconds(wallTime - deadline))
notice "Attestation sent", attestation = shortLog(attestation),
validator = shortLog(validator), delay = delayStr,
indexInCommittee = indexInCommittee
beacon_attestation_sent_delay.observe(delaySecs)
except CatchableError as exc:
# An error could happen here when the signature task fails - we must
# not leak the exception because this is an asyncSpawn task
notice "Error sending attestation", err = exc.msg
proc getBlockProposalEth1Data*(node: BeaconNode,
stateData: StateData): BlockProposalEth1Data =
if node.eth1Monitor.isNil:
var pendingDepositsCount =
getStateField(stateData, eth1_data).deposit_count -
getStateField(stateData, eth1_deposit_index)
if pendingDepositsCount > 0:
result.hasMissingDeposits = true
else:
result.vote = getStateField(stateData, eth1_data)
else:
let finalizedEpochRef = node.chainDag.getFinalizedEpochRef()
result = node.eth1Monitor.getBlockProposalData(
stateData.data.data, finalizedEpochRef.eth1_data,
finalizedEpochRef.eth1_deposit_index)
proc makeBeaconBlockForHeadAndSlot*(node: BeaconNode,
randao_reveal: ValidatorSig,
validator_index: ValidatorIndex,
graffiti: GraffitiBytes,
head: BlockRef,
slot: Slot): Option[BeaconBlock] =
# Advance state to the slot that we're proposing for
let
proposalState = assignClone(node.chainDag.headState)
proposalStateAddr = unsafeAddr proposalState[]
node.chainDag.withState(proposalState[], head.atSlot(slot)):
let
eth1Proposal = node.getBlockProposalEth1Data(stateData)
poolPtr = unsafeAddr node.chainDag # safe because restore is short-lived
if eth1Proposal.hasMissingDeposits:
error "Eth1 deposits not available. Skipping block proposal", slot
return none(BeaconBlock)
func restore(v: var HashedBeaconState) =
# TODO address this ugly workaround - there should probably be a
# `state_transition` that takes a `StateData` instead and updates
# the block as well
doAssert v.addr == addr proposalStateAddr.data
assign(proposalStateAddr[], poolPtr.headState)
makeBeaconBlock(
node.runtimePreset,
hashedState,
validator_index,
head.root,
randao_reveal,
eth1Proposal.vote,
graffiti,
node.attestationPool[].getAttestationsForBlock(state, cache),
eth1Proposal.deposits,
node.exitPool[].getProposerSlashingsForBlock(),
node.exitPool[].getAttesterSlashingsForBlock(),
node.exitPool[].getVoluntaryExitsForBlock(),
restore,
cache)
proc proposeSignedBlock*(node: BeaconNode,
head: BlockRef,
validator: AttachedValidator,
newBlock: SignedBeaconBlock): BlockRef =
let newBlockRef = node.chainDag.addRawBlock(node.quarantine, newBlock) do (
blckRef: BlockRef, trustedBlock: TrustedSignedBeaconBlock,
epochRef: EpochRef, state: HashedBeaconState):
# Callback add to fork choice if signed block valid (and becomes trusted)
node.attestationPool[].addForkChoice(
epochRef, blckRef, trustedBlock.message,
node.beaconClock.now().slotOrZero())
if newBlockRef.isErr:
warn "Unable to add proposed block to block pool",
newBlock = shortLog(newBlock.message),
blockRoot = shortLog(newBlock.root)
return head
notice "Block proposed",
blck = shortLog(newBlock.message),
blockRoot = shortLog(newBlockRef[].root),
validator = shortLog(validator)
if node.config.dumpEnabled:
dump(node.config.dumpDirOutgoing, newBlock)
node.network.broadcast(node.topicBeaconBlocks, newBlock)
beacon_blocks_proposed.inc()
return newBlockRef[]
proc proposeBlock(node: BeaconNode,
validator: AttachedValidator,
validator_index: ValidatorIndex,
head: BlockRef,
slot: Slot): Future[BlockRef] {.async.} =
if head.slot >= slot:
# We should normally not have a head newer than the slot we're proposing for
# but this can happen if block proposal is delayed
warn "Skipping proposal, have newer head already",
headSlot = shortLog(head.slot),
headBlockRoot = shortLog(head.root),
slot = shortLog(slot)
return head
let
fork = getStateField(node.chainDag.headState, fork)
genesis_validators_root =
getStateField(node.chainDag.headState, genesis_validators_root)
randao = await validator.genRandaoReveal(
fork, genesis_validators_root, slot)
message = makeBeaconBlockForHeadAndSlot(
node, randao, validator_index, node.graffitiBytes, head, slot)
if not message.isSome():
return head # already logged elsewhere!
var
newBlock = SignedBeaconBlock(
message: message.get()
)
newBlock.root = hash_tree_root(newBlock.message)
# TODO: recomputed in block proposal
let signing_root = compute_block_root(
fork, genesis_validators_root, slot, newBlock.root)
let notSlashable = node.attachedValidators
.slashingProtection
.registerBlock(validator_index, validator.pubkey, slot, signing_root)
if notSlashable.isErr:
warn "Slashing protection activated",
validator = validator.pubkey,
slot = slot,
existingProposal = notSlashable.error
return head
newBlock.signature = await validator.signBlockProposal(
fork, genesis_validators_root, slot, newBlock.root)
return node.proposeSignedBlock(head, validator, newBlock)
proc handleAttestations(node: BeaconNode, head: BlockRef, slot: Slot) =
## Perform all attestations that the validators attached to this node should
## perform during the given slot
if slot + SLOTS_PER_EPOCH < head.slot:
# The latest block we know about is a lot newer than the slot we're being
# asked to attest to - this makes it unlikely that it will be included
# at all.
# TODO the oldest attestations allowed are those that are older than the
# finalized epoch.. also, it seems that posting very old attestations
# is risky from a slashing perspective. More work is needed here.
warn "Skipping attestation, head is too recent",
headSlot = shortLog(head.slot),
slot = shortLog(slot)
return
let attestationHead = head.atSlot(slot)
if head != attestationHead.blck:
# In rare cases, such as when we're busy syncing or just slow, we'll be
# attesting to a past state - we must then recreate the world as it looked
# like back then
notice "Attesting to a state in the past, falling behind?",
headSlot = shortLog(head.slot),
attestationHeadSlot = shortLog(attestationHead.slot),
attestationSlot = shortLog(slot)
trace "Checking attestations",
attestationHeadRoot = shortLog(attestationHead.blck.root),
attestationSlot = shortLog(slot)
# We need to run attestations exactly for the slot that we're attesting to.
# In case blocks went missing, this means advancing past the latest block
# using empty slots as fillers.
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/validator.md#validator-assignments
let
epochRef = node.chainDag.getEpochRef(
attestationHead.blck, slot.compute_epoch_at_slot())
committees_per_slot = get_committee_count_per_slot(epochRef)
fork = getStateField(node.chainDag.headState, fork)
genesis_validators_root =
getStateField(node.chainDag.headState, genesis_validators_root)
for committee_index in get_committee_indices(epochRef):
let committee = get_beacon_committee(epochRef, slot, committee_index)
for index_in_committee, validator_index in committee:
let validator = node.getAttachedValidator(epochRef, validator_index)
if validator == nil:
continue
let
data = makeAttestationData(epochRef, attestationHead, committee_index)
# TODO signing_root is recomputed in produceAndSignAttestation/signAttestation just after
signing_root = compute_attestation_root(
fork, genesis_validators_root, data)
registered = node.attachedValidators
.slashingProtection
.registerAttestation(
validator_index,
validator.pubkey,
data.source.epoch,
data.target.epoch,
signing_root)
if registered.isOk():
let subnet_id = compute_subnet_for_attestation(
committees_per_slot, data.slot, data.index.CommitteeIndex)
asyncSpawn createAndSendAttestation(
node, fork, genesis_validators_root, validator, data,
committee.len(), index_in_committee, subnet_id)
else:
warn "Slashing protection activated for attestation",
validator = validator.pubkey,
badVoteDetails = $registered.error()
proc handleProposal(node: BeaconNode, head: BlockRef, slot: Slot):
Future[BlockRef] {.async.} =
## Perform the proposal for the given slot, iff we have a validator attached
## that is supposed to do so, given the shuffling at that slot for the given
## head - to compute the proposer, we need to advance a state to the given
## slot
let proposer = node.chainDag.getProposer(head, slot)
if proposer.isNone():
return head
let validator =
node.attachedValidators[].getValidator(proposer.get()[1])
if validator != nil:
return await proposeBlock(node, validator, proposer.get()[0], head, slot)
debug "Expecting block proposal",
headRoot = shortLog(head.root),
slot = shortLog(slot),
proposer_index = proposer.get()[0],
proposer = shortLog(proposer.get()[1])
return head
proc broadcastAggregatedAttestations(
node: BeaconNode, aggregationHead: BlockRef, aggregationSlot: Slot) {.async.} =
# The index is via a
# locally attested validator. Unlike in handleAttestations(...) there's a
# single one at most per slot (because that's how aggregation attestation
# works), so the machinery that has to handle looping across, basically a
# set of locally attached validators is in principle not necessary, but a
# way to organize this. Then the private key for that validator should be
# the corresponding one -- whatver they are, they match.
let
epochRef = node.chainDag.getEpochRef(aggregationHead, aggregationSlot.epoch)
fork = getStateField(node.chainDag.headState, fork)
genesis_validators_root =
getStateField(node.chainDag.headState, genesis_validators_root)
committees_per_slot = get_committee_count_per_slot(epochRef)
var
slotSigs: seq[Future[ValidatorSig]] = @[]
slotSigsData: seq[tuple[committee_index: uint64,
validator_idx: ValidatorIndex,
v: AttachedValidator]] = @[]
for committee_index in 0'u64..<committees_per_slot:
let committee = get_beacon_committee(
epochRef, aggregationSlot, committee_index.CommitteeIndex)
for index_in_committee, validatorIdx in committee:
let validator = node.getAttachedValidator(epochRef, validatorIdx)
if validator != nil:
# the validator index and private key pair.
slotSigs.add getSlotSig(validator, fork,
genesis_validators_root, aggregationSlot)
slotSigsData.add (committee_index, validatorIdx, validator)
await allFutures(slotSigs)
for curr in zip(slotSigsData, slotSigs):
let aggregateAndProof =
aggregate_attestations(node.attestationPool[], epochRef, aggregationSlot,
curr[0].committee_index.CommitteeIndex,
curr[0].validator_idx,
curr[1].read)
# Don't broadcast when, e.g., this node isn't aggregator
if aggregateAndProof.isSome:
let sig = await signAggregateAndProof(curr[0].v,
aggregateAndProof.get, fork, genesis_validators_root)
var signedAP = SignedAggregateAndProof(
message: aggregateAndProof.get,
signature: sig)
node.network.broadcast(node.topicAggregateAndProofs, signedAP)
notice "Aggregated attestation sent",
attestation = shortLog(signedAP.message.aggregate),
validator = shortLog(curr[0].v),
aggregationSlot
proc updateValidatorMetrics*(node: BeaconNode) =
when defined(metrics):
# Technically, this only needs to be done on epoch transitions and if there's
# a reorg that spans an epoch transition, but it's easier to implement this
# way for now..
# We'll limit labelled metrics to the first 64, so that we don't overload
# prom
template state: untyped = node.chainDag.headState.data.data
var total: Gwei
var i = 0
for _, v in node.attachedValidators[].validators:
let balance =
if v.index.isNone():
0.Gwei
elif v.index.get().uint64 >= state.balances.lenu64:
debug "Cannot get validator balance, index out of bounds",
pubkey = shortLog(v.pubkey), index = v.index.get(),
balances = state.balances.len,
stateRoot = node.chainDag.headState.data.root
0.Gwei
else:
state.balances[v.index.get()]
if i < 64:
attached_validator_balance.set(
balance.toGaugeValue, labelValues = [shortLog(v.pubkey)])
else:
inc i
total += balance
node.attachedValidatorBalanceTotal = total
attached_validator_balance_total.set(total.toGaugeValue)
else:
discard
proc handleValidatorDuties*(node: BeaconNode, lastSlot, slot: Slot) {.async.} =
## Perform validator duties - create blocks, vote and aggregate existing votes
if node.attachedValidators[].count == 0:
# Nothing to do because we have no validator attached
return
# The chainDag 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.chainDag.head
if not node.isSynced(head):
notice "Syncing in progress; skipping validator duties for now",
slot, headSlot = head.slot
# Rewards will be growing though, as we sync..
updateValidatorMetrics(node)
return
var curSlot = lastSlot + 1
# If broadcastStartEpoch is 0, it hasn't had time to initialize yet, which
# means that it'd be okay not to continue, but it won't gossip regardless.
if curSlot.epoch <
node.processor[].doppelgangerDetection.broadcastStartEpoch and
node.config.doppelgangerDetection:
debug "Waiting to gossip out to detect potential duplicate validators",
broadcastStartEpoch =
node.processor[].doppelgangerDetection.broadcastStartEpoch
return
# Start by checking if there's work we should have done in the past that we
# can still meaningfully do
while curSlot < slot:
notice "Catching up on validator duties",
curSlot = shortLog(curSlot),
lastSlot = shortLog(lastSlot),
slot = shortLog(slot)
# For every slot we're catching up, we'll propose then send
# attestations - head should normally be advancing along the same branch
# in this case
head = await handleProposal(node, head, curSlot)
# For each slot we missed, we need to send out attestations - if we were
# proposing during this time, we'll use the newly proposed head, else just
# keep reusing the same - the attestation that goes out will actually
# rewind the state to what it looked like at the time of that slot
handleAttestations(node, head, curSlot)
curSlot += 1
head = await handleProposal(node, head, slot)
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/validator.md#attesting
# Milliseconds to wait from the start of the slot before sending out
# attestations
const attestationOffset = SECONDS_PER_SLOT.int64 * 1000 div 3
let
# The latest point in time when we'll be sending out attestations
attestationCutoffTime = slot.toBeaconTime(millis(attestationOffset))
attestationCutoff = node.beaconClock.fromNow(attestationCutoffTime)
if attestationCutoff.inFuture:
debug "Waiting to send attestations",
head = shortLog(head),
attestationCutoff = shortLog(attestationCutoff.offset)
# Wait either for the block or the attestation cutoff time to arrive
if await node.consensusManager[].expectBlock(slot).withTimeout(attestationCutoff.offset):
# The expected block arrived (or expectBlock was called again which
# shouldn't happen as this is the only place we use it) - in our async
# loop however, we might have been doing other processing that caused delays
# here so we'll cap the waiting to the time when we would have sent out
# attestations had the block not arrived.
# An opposite case is that we received (or produced) a block that has
# not yet reached our neighbours. To protect against our attestations
# being dropped (because the others have not yet seen the block), we'll
# impose a minimum delay of 250ms. The delay is enforced only when we're
# not hitting the "normal" cutoff time for sending out attestations.
const afterBlockDelay = 250
let
afterBlockTime = node.beaconClock.now() + millis(afterBlockDelay)
afterBlockCutoff = node.beaconClock.fromNow(
min(afterBlockTime, attestationCutoffTime))
if afterBlockCutoff.inFuture:
debug "Got block, waiting to send attestations",
head = shortLog(head),
afterBlockCutoff = shortLog(afterBlockCutoff.offset)
await sleepAsync(afterBlockCutoff.offset)
# Time passed - we might need to select a new head in that case
node.consensusManager[].updateHead(slot)
head = node.chainDag.head
handleAttestations(node, head, slot)
updateValidatorMetrics(node) # the important stuff is done, update the vanity numbers
# https://github.com/ethereum/eth2.0-specs/blob/v1.0.1/specs/phase0/validator.md#broadcast-aggregate
# If the validator is selected to aggregate (is_aggregator), then they
# broadcast their best aggregate as a SignedAggregateAndProof to the global
# aggregate channel (beacon_aggregate_and_proof) two-thirds of the way
# through the slot-that is, SECONDS_PER_SLOT * 2 / 3 seconds after the start
# of slot.
if slot > 2:
let
aggregateWaitTime = node.beaconClock.fromNow(
slot.toBeaconTime(seconds(int64(SECONDS_PER_SLOT * 2) div 3)))
if aggregateWaitTime.inFuture:
debug "Waiting to send aggregate attestations",
aggregateWaitTime = shortLog(aggregateWaitTime.offset)
await sleepAsync(aggregateWaitTime.offset)
await broadcastAggregatedAttestations(node, head, slot)
if node.eth1Monitor != nil and (slot mod SLOTS_PER_EPOCH) == 0:
let finalizedEpochRef = node.chainDag.getFinalizedEpochRef()
discard node.eth1Monitor.trackFinalizedState(
finalizedEpochRef.eth1_data, finalizedEpochRef.eth1_deposit_index)