nimbus-eth2/beacon_chain/consensus_object_pools/blockchain_dag.nim

1950 lines
72 KiB
Nim

# beacon_chain
# Copyright (c) 2018-2022 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
std/[algorithm, options, sequtils, tables, sets],
stew/[assign2, byteutils, results],
metrics, snappy, chronicles,
../spec/[beaconstate, eth2_merkleization, eth2_ssz_serialization, helpers,
state_transition, validator],
".."/beacon_chain_db,
../spec/datatypes/[phase0, altair, bellatrix],
"."/[block_pools_types, block_quarantine]
export
eth2_merkleization, eth2_ssz_serialization,
block_pools_types, results, beacon_chain_db
# https://github.com/ethereum/eth2.0-metrics/blob/master/metrics.md#interop-metrics
declareGauge beacon_head_root, "Root of the head block of the beacon chain"
declareGauge beacon_head_slot, "Slot of the head block of the beacon chain"
# https://github.com/ethereum/eth2.0-metrics/blob/master/metrics.md#interop-metrics
declareGauge beacon_finalized_epoch, "Current finalized epoch" # On epoch transition
declareGauge beacon_finalized_root, "Current finalized root" # On epoch transition
declareGauge beacon_current_justified_epoch, "Current justified epoch" # On epoch transition
declareGauge beacon_current_justified_root, "Current justified root" # On epoch transition
declareGauge beacon_previous_justified_epoch, "Current previously justified epoch" # On epoch transition
declareGauge beacon_previous_justified_root, "Current previously justified root" # On epoch transition
declareGauge beacon_reorgs_total_total, "Total occurrences of reorganizations of the chain" # On fork choice; backwards-compat name (used to be a counter)
declareGauge beacon_reorgs_total, "Total occurrences of reorganizations of the chain" # Interop copy
declareCounter beacon_state_data_cache_hits, "EpochRef hits"
declareCounter beacon_state_data_cache_misses, "EpochRef misses"
declareCounter beacon_state_rewinds, "State database rewinds"
declareGauge beacon_active_validators, "Number of validators in the active validator set"
declareGauge beacon_current_active_validators, "Number of validators in the active validator set" # Interop copy
declareGauge beacon_pending_deposits, "Number of pending deposits (state.eth1_data.deposit_count - state.eth1_deposit_index)" # On block
declareGauge beacon_processed_deposits_total, "Number of total deposits included on chain" # On block
logScope: topics = "chaindag"
const
# When finality happens, we prune historical states from the database except
# for a snapshort every 32 epochs from which replays can happen - there's a
# balance here between making long replays and saving on disk space
EPOCHS_PER_STATE_SNAPSHOT = 32
proc putBlock*(
dag: ChainDAGRef, signedBlock: ForkyTrustedSignedBeaconBlock) =
dag.db.putBlock(signedBlock)
proc updateState*(
dag: ChainDAGRef, state: var ForkedHashedBeaconState, bs: BlockSlot, save: bool,
cache: var StateCache): bool {.gcsafe.}
template withStateVars*(
stateInternal: var ForkedHashedBeaconState, body: untyped): untyped =
## Inject a few more descriptive names for the members of `stateData` -
## the stateData instance may get mutated through these names as well
template state(): ForkedHashedBeaconState {.inject, used.} = stateInternal
template stateRoot(): Eth2Digest {.inject, used.} =
getStateRoot(stateInternal)
body
template withUpdatedState*(
dag: ChainDAGRef, state: var ForkedHashedBeaconState,
blockSlot: BlockSlot, okBody: untyped, failureBody: untyped): untyped =
## Helper template that updates stateData to a particular BlockSlot - usage of
## stateData is unsafe outside of block, or across `await` boundaries
block:
var cache {.inject.} = StateCache()
if updateState(dag, state, blockSlot, false, cache):
template blck(): BlockRef {.inject, used.} = blockSlot.blck
withStateVars(state):
okBody
else:
failureBody
func get_effective_balances(validators: openArray[Validator], epoch: Epoch):
seq[Gwei] =
## Get the balances from a state as counted for fork choice
result.newSeq(validators.len) # zero-init
for i in 0 ..< result.len:
# All non-active validators have a 0 balance
let validator = unsafeAddr validators[i]
if validator[].is_active_validator(epoch):
result[i] = validator[].effective_balance
proc updateValidatorKeys*(dag: ChainDAGRef, validators: openArray[Validator]) =
# Update validator key cache - must be called every time a valid block is
# applied to the state - this is important to ensure that when we sync blocks
# without storing a state (non-epoch blocks essentially), the deposits from
# those blocks are persisted to the in-database cache of immutable validator
# data (but no earlier than that the whole block as been validated)
dag.db.updateImmutableValidators(validators)
proc updateFinalizedBlocks*(dag: ChainDAGRef) =
if dag.db.db.readOnly: return # TODO abstraction leak - where to put this?
dag.db.withManyWrites:
let high = dag.db.finalizedBlocks.high.expect(
"wrote at least tailRef during init")
for s in high + 1 .. dag.finalizedHead.slot:
let tailIdx = int(s - dag.tail.slot)
if not isNil(dag.finalizedBlocks[tailIdx]):
dag.db.finalizedBlocks.insert(s, dag.finalizedBlocks[tailIdx].root)
func validatorKey*(
dag: ChainDAGRef, index: ValidatorIndex or uint64): Option[CookedPubKey] =
## Returns the validator pubkey for the index, assuming it's been observed
## at any point in time - this function may return pubkeys for indicies that
## are not (yet) part of the head state (if the key has been observed on a
## non-head branch)!
dag.db.immutableValidators.load(index)
func validatorKey*(
epochRef: EpochRef, index: ValidatorIndex or uint64): Option[CookedPubKey] =
## Returns the validator pubkey for the index, assuming it's been observed
## at any point in time - this function may return pubkeys for indicies that
## are not (yet) part of the head state (if the key has been observed on a
## non-head branch)!
validatorKey(epochRef.dag, index)
func init*(
T: type EpochRef, dag: ChainDAGRef, state: ForkedHashedBeaconState,
blck: BlockRef, cache: var StateCache): T =
let
epoch = state.get_current_epoch()
proposer_dependent_root = withState(state): state.proposer_dependent_root
attester_dependent_root = withState(state): state.attester_dependent_root
epochRef = EpochRef(
dag: dag, # This gives access to the validator pubkeys through an EpochRef
key: blck.epochAncestor(epoch),
eth1_data: getStateField(state, eth1_data),
eth1_deposit_index: getStateField(state, eth1_deposit_index),
current_justified_checkpoint:
getStateField(state, current_justified_checkpoint),
finalized_checkpoint: getStateField(state, finalized_checkpoint),
proposer_dependent_root: proposer_dependent_root,
shuffled_active_validator_indices:
cache.get_shuffled_active_validator_indices(state, epoch),
attester_dependent_root: attester_dependent_root,
merge_transition_complete:
case state.kind:
of BeaconStateFork.Phase0: false
of BeaconStateFork.Altair: false
of BeaconStateFork.Bellatrix:
# https://github.com/ethereum/consensus-specs/blob/v1.1.7/specs/merge/beacon-chain.md#is_merge_transition_complete
state.bellatrixData.data.latest_execution_payload_header !=
ExecutionPayloadHeader()
)
epochStart = epoch.start_slot()
doAssert epochRef.key.blck != nil, "epochAncestor should not fail for state block"
for i in 0'u64..<SLOTS_PER_EPOCH:
epochRef.beacon_proposers[i] = get_beacon_proposer_index(
state, cache, epochStart + i)
# When fork choice runs, it will need the effective balance of the justified
# checkpoint - we pre-load the balances here to avoid rewinding the justified
# state later and compress them because not all checkpoints end up being used
# for fork choice - specially during long periods of non-finalization
proc snappyEncode(inp: openArray[byte]): seq[byte] =
try:
snappy.encode(inp)
except CatchableError as err:
raiseAssert err.msg
epochRef.effective_balances_bytes =
snappyEncode(SSZ.encode(
List[Gwei, Limit VALIDATOR_REGISTRY_LIMIT](
get_effective_balances(getStateField(state, validators).asSeq, epoch))))
epochRef
func effective_balances*(epochRef: EpochRef): seq[Gwei] =
try:
SSZ.decode(snappy.decode(epochRef.effective_balances_bytes, uint32.high),
List[Gwei, Limit VALIDATOR_REGISTRY_LIMIT]).toSeq()
except CatchableError as exc:
raiseAssert exc.msg
func getBlockRef*(dag: ChainDAGRef, root: Eth2Digest): Opt[BlockRef] =
## Retrieve a resolved block reference, if available - this function does
## not return historical finalized blocks, see `getBlockAtSlot` for a function
## that covers the entire known history
let key = KeyedBlockRef.asLookupKey(root)
# HashSet lacks the api to do check-and-get in one lookup - `[]` will return
# the copy of the instance in the set which has more fields than `root` set!
if key in dag.forkBlocks:
try: ok(dag.forkBlocks[key].blockRef())
except KeyError: raiseAssert "contains"
else:
err()
func getBlockAtSlot*(dag: ChainDAGRef, slot: Slot): Opt[BlockSlot] =
## Retrieve the canonical block at the given slot, or the last block that
## comes before - similar to atSlot, but without the linear scan - see
## getBlockIdAtSlot for a version that covers backfill blocks as well
## May return an empty BlockSlot (where blck is nil!)
if slot == dag.genesis.slot:
return ok dag.genesis.atSlot(slot)
if slot > dag.finalizedHead.slot:
return ok dag.head.atSlot(slot) # Linear iteration is the fastest we have
doAssert dag.finalizedHead.slot >= dag.tail.slot
doAssert dag.tail.slot >= dag.backfill.slot
doAssert dag.finalizedBlocks.len ==
(dag.finalizedHead.slot - dag.tail.slot).int + 1, "see updateHead"
if slot >= dag.tail.slot:
var pos = int(slot - dag.tail.slot)
while true:
if dag.finalizedBlocks[pos] != nil:
return ok dag.finalizedBlocks[pos].atSlot(slot)
doAssert pos > 0, "We should have returned the tail"
pos = pos - 1
err() # Not found
func getBlockIdAtSlot*(dag: ChainDAGRef, slot: Slot): Opt[BlockSlotId] =
## Retrieve the canonical block at the given slot, or the last block that
## comes before - similar to atSlot, but without the linear scan - may hit
## the database to look up early indices.
let bs = dag.getBlockAtSlot(slot) # Try looking in recent blocks first
if bs.isSome:
return bs.get().toBlockSlotId()
let finlow = dag.db.finalizedBlocks.low.expect("at least tailRef written")
if slot >= finlow:
var pos = slot
while true:
let root = dag.db.finalizedBlocks.get(pos)
if root.isSome():
return ok BlockSlotId.init(
BlockId(root: root.get(), slot: pos), slot)
doAssert pos > finlow, "We should have returned the finlow"
pos = pos - 1
err() # not backfilled yet, and not genesis
proc getBlockId*(dag: ChainDAGRef, root: Eth2Digest): Opt[BlockId] =
## Look up block id by root in history - useful for turning a root into a
## slot - may hit the database, may return blocks that have since become
## unviable - use `getBlockIdAtSlot` to check that the block is still viable
## if used in a sensitive context
block: # If we have a BlockRef, this is the fastest way to get a block id
let blck = dag.getBlockRef(root)
if blck.isOk():
return ok(blck.get().bid)
block: # We might have a summary in the database
let summary = dag.db.getBeaconBlockSummary(root)
if summary.isOk():
return ok(BlockId(root: root, slot: summary.get().slot))
err()
func isCanonical*(dag: ChainDAGRef, bid: BlockId): bool =
let current = dag.getBlockIdAtSlot(bid.slot).valueOr:
return false # We don't know, so ..
return current.bid == bid
func epochAncestor*(blck: BlockRef, epoch: Epoch): EpochKey =
## The state transition works by storing information from blocks in a
## "working" area until the epoch transition, then batching work collected
## during the epoch. Thus, last block in the ancestor epochs is the block
## that has an impact on epoch currently considered.
##
## This function returns an epoch key pointing to that epoch boundary, i.e. the
## boundary where the last block has been applied to the state and epoch
## processing has been done.
var blck = blck
while blck.slot.epoch >= epoch and not blck.parent.isNil:
blck = blck.parent
if blck.slot.epoch > epoch:
EpochKey() # The searched-for epoch predates our tail block
else:
EpochKey(epoch: epoch, blck: blck)
func findEpochRef*(
dag: ChainDAGRef, blck: BlockRef, epoch: Epoch): Opt[EpochRef] =
## Look for an existing cached EpochRef, but unlike `getEpochRef`, don't
## try to create one by recreating the epoch state
let ancestor = epochAncestor(blck, epoch)
if isNil(ancestor.blck):
# We can't compute EpochRef instances for states before the tail because
# we do not have them!
return err()
for i in 0..<dag.epochRefs.len:
if dag.epochRefs[i] != nil and dag.epochRefs[i].key == ancestor:
return ok(dag.epochRefs[i])
err()
func loadStateCache(
dag: ChainDAGRef, cache: var StateCache, blck: BlockRef, epoch: Epoch) =
# When creating a state cache, we want the current and the previous epoch
# information to be preloaded as both of these are used in state transition
# functions
template load(e: Epoch) =
block:
let epoch = e
if epoch notin cache.shuffled_active_validator_indices:
let epochRef = dag.findEpochRef(blck, epoch)
if epochRef.isSome():
cache.shuffled_active_validator_indices[epoch] =
epochRef[].shuffled_active_validator_indices
let start_slot = epoch.start_slot()
for i, idx in epochRef[].beacon_proposers:
cache.beacon_proposer_indices[start_slot + i] = idx
load(epoch)
if epoch > 0:
load(epoch - 1)
func containsForkBlock*(dag: ChainDAGRef, root: Eth2Digest): bool =
## Checks for blocks at the finalized checkpoint or newer
KeyedBlockRef.asLookupKey(root) in dag.forkBlocks
proc containsBlock(
cfg: RuntimeConfig, db: BeaconChainDB, slot: Slot, root: Eth2Digest): bool =
db.containsBlock(root, cfg.blockForkAtEpoch(slot.epoch))
func isFinalizedStateSnapshot(slot: Slot): bool =
slot.is_epoch and slot.epoch mod EPOCHS_PER_STATE_SNAPSHOT == 0
func isStateCheckpoint(bs: BlockSlot): bool =
## State checkpoints are the points in time for which we store full state
## snapshots, which later serve as rewind starting points when replaying state
## transitions from database, for example during reorgs.
##
# As a policy, we only store epoch boundary states without the epoch block
# (if it exists) applied - the rest can be reconstructed by loading an epoch
# boundary state and applying the missing blocks.
# We also avoid states that were produced with empty slots only - as such,
# there is only a checkpoint for the first epoch after a block.
# The tail block also counts as a state checkpoint!
(bs.slot == bs.blck.slot and bs.blck.parent == nil) or
(bs.slot.is_epoch and bs.slot.epoch == (bs.blck.slot.epoch + 1))
proc getState(
db: BeaconChainDB, cfg: RuntimeConfig, slot: Slot, state_root: Eth2Digest,
state: var ForkedHashedBeaconState, rollback: RollbackProc): bool =
let expectedFork = cfg.stateForkAtEpoch(slot.epoch)
if state.kind != expectedFork:
# Avoid temporary (!)
state = (ref ForkedHashedBeaconState)(kind: expectedFork)[]
let ok = withState(state):
db.getState(state_root, state.data, rollback)
if not ok:
return false
setStateRoot(state, state_root)
true
proc getState(
db: BeaconChainDB, cfg: RuntimeConfig, state: var ForkedHashedBeaconState,
bs: BlockSlot, rollback: RollbackProc): bool =
if not bs.isStateCheckpoint():
return false
let root = db.getStateRoot(bs.blck.root, bs.slot)
if not root.isSome():
return false
if not db.getState(cfg, bs.slot, root.get(), state, rollback):
return false
true
proc getForkedBlock*(db: BeaconChainDB, root: Eth2Digest):
Opt[ForkedTrustedSignedBeaconBlock] =
# When we only have a digest, we don't know which fork it's from so we try
# them one by one - this should be used sparingly
if (let blck = db.getBlock(root, bellatrix.TrustedSignedBeaconBlock);
blck.isSome()):
ok(ForkedTrustedSignedBeaconBlock.init(blck.get()))
elif (let blck = db.getBlock(root, altair.TrustedSignedBeaconBlock);
blck.isSome()):
ok(ForkedTrustedSignedBeaconBlock.init(blck.get()))
elif (let blck = db.getBlock(root, phase0.TrustedSignedBeaconBlock);
blck.isSome()):
ok(ForkedTrustedSignedBeaconBlock.init(blck.get()))
else:
err()
proc getBlock*(
dag: ChainDAGRef, bid: BlockId,
T: type ForkyTrustedSignedBeaconBlock): Opt[T] =
withState(dag.headState):
dag.db.getBlock(bid.root, T)
proc getBlockSSZ*(dag: ChainDAGRef, bid: BlockId, bytes: var seq[byte]): bool =
# Load the SSZ-encoded data of a block into `bytes`, overwriting the existing
# content
# careful: there are two snappy encodings in use, with and without framing!
# Returns true if the block is found, false if not
let fork = dag.cfg.blockForkAtEpoch(bid.slot.epoch)
dag.db.getBlockSSZ(bid.root, bytes, fork)
proc getForkedBlock*(
dag: ChainDAGRef, bid: BlockId): Opt[ForkedTrustedSignedBeaconBlock] =
let fork = dag.cfg.blockForkAtEpoch(bid.slot.epoch)
result.ok(ForkedTrustedSignedBeaconBlock(kind: fork))
withBlck(result.get()):
type T = type(blck)
blck = getBlock(dag, bid, T).valueOr:
result.err()
return
proc getForkedBlock*(
dag: ChainDAGRef, root: Eth2Digest): Opt[ForkedTrustedSignedBeaconBlock] =
let bid = dag.getBlockId(root)
if bid.isSome():
dag.getForkedBlock(bid.get())
else:
# In case we didn't have a summary - should be rare, but ..
dag.db.getForkedBlock(root)
proc updateBeaconMetrics(
state: ForkedHashedBeaconState, bid: BlockId, cache: var StateCache) =
# https://github.com/ethereum/eth2.0-metrics/blob/master/metrics.md#additional-metrics
# both non-negative, so difference can't overflow or underflow int64
beacon_head_root.set(bid.root.toGaugeValue)
beacon_head_slot.set(bid.slot.toGaugeValue)
withState(state):
beacon_pending_deposits.set(
(state.data.eth1_data.deposit_count -
state.data.eth1_deposit_index).toGaugeValue)
beacon_processed_deposits_total.set(
state.data.eth1_deposit_index.toGaugeValue)
beacon_current_justified_epoch.set(
state.data.current_justified_checkpoint.epoch.toGaugeValue)
beacon_current_justified_root.set(
state.data.current_justified_checkpoint.root.toGaugeValue)
beacon_previous_justified_epoch.set(
state.data.previous_justified_checkpoint.epoch.toGaugeValue)
beacon_previous_justified_root.set(
state.data.previous_justified_checkpoint.root.toGaugeValue)
beacon_finalized_epoch.set(
state.data.finalized_checkpoint.epoch.toGaugeValue)
beacon_finalized_root.set(
state.data.finalized_checkpoint.root.toGaugeValue)
let active_validators = count_active_validators(
state.data, state.data.slot.epoch, cache).toGaugeValue
beacon_active_validators.set(active_validators)
beacon_current_active_validators.set(active_validators)
import blockchain_dag_light_client
export
blockchain_dag_light_client.getBestLightClientUpdateForPeriod,
blockchain_dag_light_client.getLatestLightClientUpdate,
blockchain_dag_light_client.getOptimisticLightClientUpdate,
blockchain_dag_light_client.getLightClientBootstrap
proc init*(T: type ChainDAGRef, cfg: RuntimeConfig, db: BeaconChainDB,
validatorMonitor: ref ValidatorMonitor, updateFlags: UpdateFlags,
onBlockCb: OnBlockCallback = nil, onHeadCb: OnHeadCallback = nil,
onReorgCb: OnReorgCallback = nil,
onFinCb: OnFinalizedCallback = nil,
onOptimisticLCUpdateCb: OnOptimisticLightClientUpdateCallback = nil,
serveLightClientData = false,
importLightClientData = ImportLightClientData.None
): ChainDAGRef =
# TODO we require that the db contains both a head and a tail block -
# asserting here doesn't seem like the right way to go about it however..
# Tail is the first block for which we can construct a state - either
# genesis or a checkpoint
let
startTick = Moment.now()
tailRoot = db.getTailBlock().expect("Tail root in database, corrupt?")
tailBlock = db.getForkedBlock(tailRoot).expect(
"Tail block in database, corrupt?")
tailRef = withBlck(tailBlock): BlockRef.init(tailRoot, blck.message)
# Backfills are blocks that we have in the database, but can't construct a
# state for without replaying from genesis
var
# The most recent block that we load from the finalized blocks table
midRef: BlockRef
# Start by loading basic block information about finalized blocks - this
# generally goes from genesis (or the earliest backfilled block) all the way
# to the latest block finalized in the `head` history - we have to be careful
# though, versions prior to 1.7.0 did not store finalized blocks in the
# database, and / or the application might have crashed between the head and
# finalized blocks updates.
for slot, root in db.finalizedBlocks:
if slot < tailRef.slot:
discard # TODO don't load this range at all from the database
elif slot == tailRef.slot:
if root != tailRef.root:
fatal "Finalized blocks do not meet with tail, database corrupt?",
tail = shortLog(tailRef), root = shortLog(root)
quit 1
midRef = tailRef
else: # slot > tailRef.slot
if midRef == nil:
fatal "First finalized block beyond tail, database corrupt?",
tail = shortLog(tailRef), slot, root = shortLog(root)
quit 1
let next = BlockRef.init(root, slot)
link(midRef, next)
midRef = next
let
finalizedTick = Moment.now()
headRoot = db.getHeadBlock().expect("Head root in database, corrupt?")
var
headRef: BlockRef
curRef: BlockRef
finalizedBlocks = newSeq[Eth2Digest](
if midRef == nil: tailRef.slot.int + 1
else: 0
)
# Load the part from head going backwards - if we found any entries in the
# finalized block table, we'll stop at `midRef`, otherwise we'll keep going
# as far as we can find headers and fill in the finalized blocks from tail
for blck in db.getAncestorSummaries(headRoot):
if midRef != nil and blck.summary.slot <= midRef.slot:
if midRef.slot != blck.summary.slot or midRef.root != blck.root:
fatal "Finalized block table does not match ancestor summaries, database corrupt?",
head = shortLog(headRoot), cur = shortLog(curRef),
mid = shortLog(midRef), blck = shortLog(blck.root)
quit 1
if curRef == nil:
# When starting from checkpoint, head == tail and there won't be any
# blocks in between
headRef = tailRef
else:
link(midRef, curRef)
# The finalized blocks form a linear history by definition - we can skip
# straight to the tail
curRef = tailRef
break
if blck.summary.slot < tailRef.slot:
doAssert midRef == nil,
"If we loaded any blocks from the finalized slot table, they should have included tailRef"
finalizedBlocks[blck.summary.slot.int] = blck.root
elif blck.summary.slot == tailRef.slot:
if curRef == nil:
curRef = tailRef
headRef = tailRef
else:
link(tailRef, curRef)
curRef = curRef.parent
if midRef == nil:
finalizedBlocks[blck.summary.slot.int] = blck.root
else:
let newRef = BlockRef.init(blck.root, blck.summary.slot)
if curRef == nil:
curRef = newRef
headRef = newRef
else:
link(newRef, curRef)
curRef = curRef.parent
trace "Populating block dag", key = curRef.root, val = curRef
if finalizedBlocks.len > 0 and not db.db.readOnly: # TODO abstraction leak
db.withManyWrites:
for i, root in finalizedBlocks.mpairs:
if root.isZero: continue
db.finalizedBlocks.insert(Slot(i), root)
let backfill = block:
let backfillSlot = db.finalizedBlocks.low.expect("tail at least")
if backfillSlot < tailRef.slot:
let backfillRoot = db.finalizedBlocks.get(backfillSlot).expect(
"low to be loadable")
db.getBeaconBlockSummary(backfillRoot).expect(
"Backfill block must have a summary")
else:
withBlck(tailBlock): blck.message.toBeaconBlockSummary()
let summariesTick = Moment.now()
if curRef != tailRef:
fatal "Head block does not lead to tail - database corrupt?",
tailRef, headRef, curRef, tailRoot, headRoot
quit 1
while not containsBlock(cfg, db, headRef.slot, headRef.root):
# When the database has been written with a pre-fork version of the
# software, it may happen that blocks produced using an "unforked"
# chain get written to the database - we need to skip such blocks
# when loading the database with a fork-compatible version
if isNil(headRef.parent):
fatal "Cannot find block for head root - database corrupt?",
headRef = shortLog(headRef)
headRef = headRef.parent
# Because of incorrect hardfork check, there might be no head block, in which
# case it's equivalent to the tail block
if headRef == nil:
headRef = tailRef
let genesisRef = if tailRef.slot == GENESIS_SLOT:
tailRef
else:
let
genesisRoot = db.getGenesisBlock().expect(
"preInit should have initialized the database with a genesis block root")
BlockRef.init(genesisRoot, GENESIS_SLOT)
let dag = ChainDAGRef(
db: db,
validatorMonitor: validatorMonitor,
genesis: genesisRef,
tail: tailRef,
head: headRef,
backfill: backfill,
finalizedHead: tailRef.atSlot(),
lastPrunePoint: tailRef.atSlot(),
# Tail is implicitly finalized - we'll adjust it below when computing the
# head state
heads: @[headRef],
clearanceBlck: headRef,
# The only allowed flag right now is verifyFinalization, as the others all
# allow skipping some validation.
updateFlags: {verifyFinalization} * updateFlags,
cfg: cfg,
serveLightClientData: serveLightClientData,
importLightClientData: importLightClientData,
onBlockAdded: onBlockCb,
onHeadChanged: onHeadCb,
onReorgHappened: onReorgCb,
onFinHappened: onFinCb,
onOptimisticLightClientUpdate: onOptimisticLCUpdateCb
)
block: # Initialize dag states
var
cur = headRef.atSlot()
# Now that we have a head block, we need to find the most recent state that
# we have saved in the database
while cur.blck != nil and
not getState(db, cfg, dag.headState, cur, noRollback):
cur = cur.parentOrSlot()
if cur.blck == nil:
fatal "No state found in head history, database corrupt?",
genesisRef, tailRef, headRef
# TODO Potentially we could recover from here instead of crashing - what
# would be a good recovery model?
quit 1
let
configFork = case dag.headState.kind
of BeaconStateFork.Phase0: genesisFork(cfg)
of BeaconStateFork.Altair: altairFork(cfg)
of BeaconStateFork.Bellatrix: bellatrixFork(cfg)
statefork = getStateField(dag.headState, fork)
if stateFork != configFork:
error "State from database does not match network, check --network parameter",
genesisRef, tailRef, headRef, stateFork, configFork
quit 1
# db state is likely a epoch boundary state which is what we want for epochs
assign(dag.epochRefState, dag.headState)
dag.forkDigests = newClone ForkDigests.init(
cfg, getStateField(dag.headState, genesis_validators_root))
let forkVersions =
[cfg.GENESIS_FORK_VERSION, cfg.ALTAIR_FORK_VERSION,
cfg.BELLATRIX_FORK_VERSION, cfg.SHARDING_FORK_VERSION]
for i in 0 ..< forkVersions.len:
for j in i+1 ..< forkVersions.len:
doAssert forkVersions[i] != forkVersions[j]
doAssert cfg.ALTAIR_FORK_EPOCH <= cfg.BELLATRIX_FORK_EPOCH
doAssert cfg.BELLATRIX_FORK_EPOCH <= cfg.SHARDING_FORK_EPOCH
doAssert dag.updateFlags in [{}, {verifyFinalization}]
# The state we loaded into `headState` is the last state we saved, which may
# come from earlier than the head block
var cache: StateCache
if not dag.updateState(dag.headState, headRef.atSlot(), false, cache):
fatal "Unable to load head state, database corrupt?",
head = shortLog(headRef)
quit 1
# Clearance most likely happens from head - assign it after rewinding head
assign(dag.clearanceState, dag.headState)
withState(dag.headState):
dag.validatorMonitor[].registerState(state.data)
updateBeaconMetrics(dag.headState, dag.head.bid, cache)
# The tail block is "implicitly" finalized as it was given either as a
# checkpoint block, or is the genesis, thus we use it as a lower bound when
# computing the finalized head
let
finalized_checkpoint =
getStateField(dag.headState, finalized_checkpoint)
finalizedSlot = max(finalized_checkpoint.epoch.start_slot(), tailRef.slot)
block: # Set up finalizedHead -> head
var tmp = dag.head
while tmp.slot > finalizedSlot:
dag.forkBlocks.incl(KeyedBlockRef.init(tmp))
tmp = tmp.parent
# Fork blocks always include the latest finalized block which serves as the
# "root" of the fork DAG
dag.forkBlocks.incl(KeyedBlockRef.init(tmp))
dag.finalizedHead = tmp.atSlot(finalizedSlot)
block: # Set up tail -> finalizedHead
# Room for all finalized blocks from the tail onwards
let n = (dag.finalizedHead.slot - dag.tail.slot).int + 1
# Make room for some more blocks to avoid an instant reallocation
dag.finalizedBlocks = newSeqOfCap[BlockRef](int(n * 3 / 2))
dag.finalizedBlocks.setLen(n)
var tmp = dag.finalizedHead.blck
while not isNil(tmp):
dag.finalizedBlocks[(tmp.slot - dag.tail.slot).int] = tmp
tmp = tmp.parent
let stateTick = Moment.now()
# Pruning metadata
dag.lastPrunePoint = dag.finalizedHead
# Fill validator key cache in case we're loading an old database that doesn't
# have a cache
dag.updateValidatorKeys(getStateField(dag.headState, validators).asSeq())
dag.updateFinalizedBlocks()
withState(dag.headState):
when stateFork >= BeaconStateFork.Altair:
dag.headSyncCommittees = state.data.get_sync_committee_cache(cache)
info "Block DAG initialized",
head = shortLog(dag.head),
finalizedHead = shortLog(dag.finalizedHead),
tail = shortLog(dag.tail),
backfill = (dag.backfill.slot, shortLog(dag.backfill.parent_root)),
finalizedDur = finalizedTick - startTick,
summariesDur = summariesTick - finalizedTick,
stateDur = stateTick - summariesTick,
indexDur = Moment.now() - stateTick
dag.initLightClientCache()
dag
template genesisValidatorsRoot*(dag: ChainDAGRef): Eth2Digest =
getStateField(dag.headState, genesis_validators_root)
func getEpochRef*(
dag: ChainDAGRef, state: ForkedHashedBeaconState, blck: BlockRef,
cache: var StateCache): EpochRef =
## Get a cached `EpochRef` or construct one based on the given state - always
## returns an EpochRef instance
let
epoch = state.get_current_epoch()
var epochRef = dag.findEpochRef(blck, epoch)
if epochRef.isErr:
let res = EpochRef.init(dag, state, blck, cache)
if epoch >= dag.finalizedHead.slot.epoch():
# Only cache epoch information for unfinalized blocks - earlier states
# are seldomly used (ie RPC), so no need to cache
# Because we put a cap on the number of epochRefs we store, we want to
# prune the least useful state - for now, we'll assume that to be the
# oldest epochRef we know about.
var
oldest = 0
for x in 0..<dag.epochRefs.len:
let candidate = dag.epochRefs[x]
if candidate == nil:
oldest = x
break
if candidate.key.epoch < dag.epochRefs[oldest].epoch:
oldest = x
dag.epochRefs[oldest] = res
res
else:
epochRef.get()
proc getEpochRef*(
dag: ChainDAGRef, blck: BlockRef, epoch: Epoch,
preFinalized: bool): Opt[EpochRef] =
## Return a cached EpochRef or construct one from the database, if possible -
## returns `none` on failure.
##
## When `preFinalized` is true, include epochs from before the finalized
## checkpoint in the search - this potentially can result in long processing
## times due to state replays.
##
## Requests for epochs >= dag.finalizedHead.slot.epoch always return an
## instance. One must be careful to avoid race conditions in `async` code
## where the finalized head might change during an `await`.
##
## Requests for epochs < dag.finalizedHead.slot.epoch may fail, either because
## the search was limited by the `preFinalized` flag or because state history
## has been pruned - none will be returned in this case.
if not preFinalized and epoch < dag.finalizedHead.slot.epoch:
return err()
let epochRef = dag.findEpochRef(blck, epoch)
if epochRef.isOk():
beacon_state_data_cache_hits.inc
return epochRef
beacon_state_data_cache_misses.inc
let
ancestor = epochAncestor(blck, epoch)
if isNil(ancestor.blck): # past the tail
return err()
let epochBlck = ancestor.blck.atEpochStart(ancestor.epoch)
dag.withUpdatedState(dag.epochRefState, epochBlck) do:
ok(dag.getEpochRef(state, blck, cache))
do:
err()
proc getFinalizedEpochRef*(dag: ChainDAGRef): EpochRef =
dag.getEpochRef(
dag.finalizedHead.blck, dag.finalizedHead.slot.epoch, false).expect(
"getEpochRef for finalized head should always succeed")
func stateCheckpoint*(bs: BlockSlot): BlockSlot =
## The first ancestor BlockSlot that is a state checkpoint
var bs = bs
while not isStateCheckPoint(bs):
bs = bs.parentOrSlot
bs
template forkAtEpoch*(dag: ChainDAGRef, epoch: Epoch): Fork =
forkAtEpoch(dag.cfg, epoch)
func forkDigestAtEpoch*(dag: ChainDAGRef, epoch: Epoch): ForkDigest =
case dag.cfg.stateForkAtEpoch(epoch)
of BeaconStateFork.Bellatrix: dag.forkDigests.bellatrix
of BeaconStateFork.Altair: dag.forkDigests.altair
of BeaconStateFork.Phase0: dag.forkDigests.phase0
proc getState(
dag: ChainDAGRef, state: var ForkedHashedBeaconState, bs: BlockSlot): bool =
## Load a state from the database given a block and a slot - this will first
## lookup the state root in the state root table then load the corresponding
## state, if it exists
let restoreAddr =
# Any restore point will do as long as it's not the object being updated
if unsafeAddr(state) == unsafeAddr(dag.headState):
unsafeAddr dag.clearanceState
else:
unsafeAddr dag.headState
let v = addr state
func restore() =
assign(v[], restoreAddr[])
getState(dag.db, dag.cfg, state, bs, restore)
proc putState(dag: ChainDAGRef, state: ForkedHashedBeaconState, blck: BlockRef) =
# Store a state and its root
logScope:
blck = shortLog(blck)
stateSlot = shortLog(getStateField(state, slot))
stateRoot = shortLog(getStateRoot(state))
if not isStateCheckpoint(blck.atSlot(getStateField(state, slot))):
return
# Don't consider legacy tables here, they are slow to read so we'll want to
# rewrite things in the new table anyway.
if dag.db.containsState(getStateRoot(state), legacy = false):
return
let startTick = Moment.now()
# Ideally we would save the state and the root lookup cache in a single
# transaction to prevent database inconsistencies, but the state loading code
# is resilient against one or the other going missing
withState(state):
dag.db.putState(state)
debug "Stored state", putStateDur = Moment.now() - startTick
proc getBlockRange*(
dag: ChainDAGRef, startSlot: Slot, skipStep: uint64,
output: var openArray[BlockId]): Natural =
## This function populates an `output` buffer of blocks
## with a slots ranging from `startSlot` up to, but not including,
## `startSlot + skipStep * output.len`, skipping any slots that don't have
## a block.
##
## Blocks will be written to `output` from the end without gaps, even if
## a block is missing in a particular slot. The return value shows how
## many slots were missing blocks - to iterate over the result, start
## at this index.
##
## If there were no blocks in the range, `output.len` will be returned.
let
requestedCount = output.lenu64
headSlot = dag.head.slot
trace "getBlockRange entered",
head = shortLog(dag.head.root), requestedCount, startSlot, skipStep, headSlot
if startSlot < dag.backfill.slot:
notice "Got request for pre-backfill slot",
startSlot, backfillSlot = dag.backfill.slot
return output.len
if headSlot <= startSlot or requestedCount == 0:
return output.len # Identical to returning an empty set of block as indicated above
let
runway = uint64(headSlot - startSlot)
# This is the number of blocks that will follow the start block
extraSlots = min(runway div skipStep, requestedCount - 1)
# If `skipStep` is very large, `extraSlots` should be 0 from
# the previous line, so `endSlot` will be equal to `startSlot`:
endSlot = startSlot + extraSlots * skipStep
var
curSlot = endSlot
o = output.len
# Process all blocks that follow the start block (may be zero blocks)
while curSlot > startSlot:
let bs = dag.getBlockIdAtSlot(curSlot)
if bs.isSome and bs.get().isProposed():
o -= 1
output[o] = bs.get().bid
curSlot -= skipStep
# Handle start slot separately (to avoid underflow when computing curSlot)
let bs = dag.getBlockIdAtSlot(startSlot)
if bs.isSome and bs.get().isProposed():
o -= 1
output[o] = bs.get().bid
o # Return the index of the first non-nil item in the output
proc advanceSlots(
dag: ChainDAGRef, state: var ForkedHashedBeaconState, blck: BlockRef,
slot: Slot, save: bool, cache: var StateCache, info: var ForkedEpochInfo) =
# Given a state, advance it zero or more slots by applying empty slot
# processing - the state must be positions at a slot before or equal to the
# target
doAssert getStateField(state, slot) <= slot
while getStateField(state, slot) < slot:
let preEpoch = getStateField(state, slot).epoch
loadStateCache(dag, cache, blck, getStateField(state, slot).epoch)
process_slots(
dag.cfg, state, getStateField(state, slot) + 1, cache, info,
dag.updateFlags).expect("process_slots shouldn't fail when state slot is correct")
if save:
dag.putState(state, blck)
# The reward information in the state transition is computed for epoch
# transitions - when transitioning into epoch N, the activities in epoch
# N-2 are translated into balance updates, and this is what we capture
# in the monitor. This may be inaccurate during a deep reorg (>1 epoch)
# which is an acceptable tradeoff for monitoring.
withState(state):
let postEpoch = state.data.slot.epoch
if preEpoch != postEpoch:
dag.validatorMonitor[].registerEpochInfo(postEpoch, info, state.data)
proc applyBlock(
dag: ChainDAGRef, state: var ForkedHashedBeaconState, bid: BlockId,
cache: var StateCache, info: var ForkedEpochInfo): Result[void, cstring] =
case dag.cfg.blockForkAtEpoch(bid.slot.epoch)
of BeaconBlockFork.Phase0:
let data = getBlock(dag, bid, phase0.TrustedSignedBeaconBlock).valueOr:
return err("Block load failed")
state_transition(
dag.cfg, state, data, cache, info,
dag.updateFlags + {slotProcessed}, noRollback)
of BeaconBlockFork.Altair:
let data = getBlock(dag, bid, altair.TrustedSignedBeaconBlock).valueOr:
return err("Block load failed")
state_transition(
dag.cfg, state, data, cache, info,
dag.updateFlags + {slotProcessed}, noRollback)
of BeaconBlockFork.Bellatrix:
let data = getBlock(dag, bid, bellatrix.TrustedSignedBeaconBlock).valueOr:
return err("Block load failed")
state_transition(
dag.cfg, state, data, cache, info,
dag.updateFlags + {slotProcessed}, noRollback)
proc applyBlock(
dag: ChainDAGRef,
state: var ForkedHashedBeaconState, blck: BlockRef,
cache: var StateCache, info: var ForkedEpochInfo) =
# Apply a single block to the state - the state must be positioned at the
# parent of the block with a slot lower than the one of the block being
# applied
doAssert state.matches_block(blck.parent.root)
loadStateCache(dag, cache, blck.parent, getStateField(state, slot).epoch)
dag.applyBlock(state, blck.bid, cache, info).expect(
"Blocks from database must not fail to apply")
proc updateState*(
dag: ChainDAGRef, state: var ForkedHashedBeaconState, bs: BlockSlot,
save: bool, cache: var StateCache): bool =
## Rewind or advance state such that it matches the given block and slot -
## this may include replaying from an earlier snapshot if blck is on a
## different branch or has advanced to a higher slot number than slot
## If `bs.slot` is higher than `bs.blck.slot`, `updateState` will fill in
## with empty/non-block slots
# First, see if we're already at the requested block. If we are, also check
# that the state has not been advanced past the desired block - if it has,
# an earlier state must be loaded since there's no way to undo the slot
# transitions
if isNil(bs.blck):
info "Requesting state for unknown block, historical data not available?",
head = shortLog(dag.head), tail = shortLog(dag.tail)
return false
let
startTick = Moment.now()
current {.used.} = withState(state):
BlockSlotId.init(state.latest_block_id, state.data.slot)
var
ancestors: seq[BlockRef]
found = false
template exactMatch(state: ForkedHashedBeaconState, bs: BlockSlot): bool =
# The block is the same and we're at an early enough slot - the state can
# be used to arrive at the desired blockslot
state.matches_block_slot(bs.blck.root, bs.slot)
template canAdvance(state: ForkedHashedBeaconState, bs: BlockSlot): bool =
# The block is the same and we're at an early enough slot - the state can
# be used to arrive at the desired blockslot
state.can_advance_slots(bs.blck.root, bs.slot)
# Fast path: check all caches for an exact match - this is faster than
# advancing a state where there's epoch processing to do, by a wide margin -
# it also avoids `hash_tree_root` for slot processing
if exactMatch(state, bs):
found = true
elif not save:
# When required to save states, we cannot rely on the caches because that
# would skip the extra processing that save does - not all information that
# goes into the database is cached
if exactMatch(dag.headState, bs):
assign(state, dag.headState)
found = true
elif exactMatch(dag.clearanceState, bs):
assign(state, dag.clearanceState)
found = true
elif exactMatch(dag.epochRefState, bs):
assign(state, dag.epochRefState)
found = true
const RewindBlockThreshold = 64
if not found:
# No exact match found - see if any in-memory state can be used as a base
# onto which we can apply a few blocks - there's a tradeoff here between
# loading the state from disk and performing the block applications
var cur = bs
while ancestors.len < RewindBlockThreshold:
if isNil(cur.blck): # tail reached
break
if canAdvance(state, cur): # Typical case / fast path when there's no reorg
found = true
break
if not save: # see above
if canAdvance(dag.headState, cur):
assign(state, dag.headState)
found = true
break
if canAdvance(dag.clearanceState, cur):
assign(state, dag.clearanceState)
found = true
break
if canAdvance(dag.epochRefState, cur):
assign(state, dag.epochRefState)
found = true
break
if cur.isProposed():
# This is not an empty slot, so the block will need to be applied to
# eventually reach bs
ancestors.add(cur.blck)
# Move slot by slot to capture epoch boundary states
cur = cur.parentOrSlot()
if not found:
debug "UpdateStateData cache miss",
current = shortLog(current), target = shortLog(bs)
# Either the state is too new or was created by applying a different block.
# We'll now resort to loading the state from the database then reapplying
# blocks until we reach the desired point in time.
var cur = bs
ancestors.setLen(0)
# Look for a state in the database and load it - as long as it cannot be
# found, keep track of the blocks that are needed to reach it from the
# state that eventually will be found.
# If we hit the tail, it means that we've reached a point for which we can
# no longer recreate history - this happens for example when starting from
# a checkpoint block
let startEpoch = bs.slot.epoch
while not canAdvance(state, cur) and not dag.getState(state, cur):
# There's no state saved for this particular BlockSlot combination, and
# the state we have can't trivially be advanced (in case it was older than
# RewindBlockThreshold), keep looking..
if cur.isProposed():
# This is not an empty slot, so the block will need to be applied to
# eventually reach bs
ancestors.add(cur.blck)
if cur.slot == dag.tail.slot or
(cur.slot.epoch + EPOCHS_PER_STATE_SNAPSHOT * 2 < startEpoch):
# We've either walked two full state snapshot lengths or hit the tail
# and still can't find a matching state: this can happen when
# starting the node from an arbitrary finalized checkpoint and not
# backfilling the states
notice "Request for pruned historical state",
request = shortLog(bs), tail = shortLog(dag.tail), cur = shortLog(cur)
return false
# Move slot by slot to capture epoch boundary states
cur = cur.parentOrSlot()
beacon_state_rewinds.inc()
# Starting state has been assigned, either from memory or database
let
assignTick = Moment.now()
ancestor {.used.} = withState(state):
BlockSlotId.init(state.latest_block_id, state.data.slot)
ancestorRoot {.used.} = getStateRoot(state)
var info: ForkedEpochInfo
# Time to replay all the blocks between then and now
for i in countdown(ancestors.len - 1, 0):
# Because the ancestors are in the database, there's no need to persist them
# again. Also, because we're applying blocks that were loaded from the
# database, we can skip certain checks that have already been performed
# before adding the block to the database.
dag.applyBlock(state, ancestors[i], cache, info)
# ...and make sure to process empty slots as requested
dag.advanceSlots(state, bs.blck, bs.slot, save, cache, info)
# ...and make sure to load the state cache, if it exists
loadStateCache(dag, cache, bs.blck, getStateField(state, slot).epoch)
let
assignDur = assignTick - startTick
replayDur = Moment.now() - assignTick
# TODO https://github.com/status-im/nim-chronicles/issues/108
if (assignDur + replayDur) >= 250.millis:
# This might indicate there's a cache that's not in order or a disk that is
# too slow - for now, it's here for investigative purposes and the cutoff
# time might need tuning
info "State replayed",
blocks = ancestors.len,
slots = getStateField(state, slot) - ancestor.slot,
current = shortLog(current),
ancestor = shortLog(ancestor),
target = shortLog(bs),
ancestorStateRoot = shortLog(ancestorRoot),
targetStateRoot = shortLog(getStateRoot(state)),
found,
assignDur,
replayDur
elif ancestors.len > 0:
debug "State replayed",
blocks = ancestors.len,
slots = getStateField(state, slot) - ancestor.slot,
current = shortLog(current),
ancestor = shortLog(ancestor),
target = shortLog(bs),
ancestorStateRoot = shortLog(ancestorRoot),
targetStateRoot = shortLog(getStateRoot(state)),
found,
assignDur,
replayDur
else: # Normal case!
trace "State advanced",
blocks = ancestors.len,
slots = getStateField(state, slot) - ancestor.slot,
current = shortLog(current),
ancestor = shortLog(ancestor),
target = shortLog(bs),
ancestorStateRoot = shortLog(ancestorRoot),
targetStateRoot = shortLog(getStateRoot(state)),
found,
assignDur,
replayDur
true
proc delState(dag: ChainDAGRef, bs: BlockSlot) =
# Delete state state and mapping for a particular block+slot
if not isStateCheckpoint(bs):
return # We only ever save epoch states
if (let root = dag.db.getStateRoot(bs.blck.root, bs.slot); root.isSome()):
dag.db.delState(root.get())
dag.db.delStateRoot(bs.blck.root, bs.slot)
proc pruneBlocksDAG(dag: ChainDAGRef) =
## This prunes the block DAG
## This does NOT prune the cached state checkpoints and EpochRef
## This must be done after a new finalization point is reached
## to invalidate pending blocks or attestations referring
## to a now invalid fork.
##
## This does NOT update the `dag.lastPrunePoint` field.
## as the caches and fork choice can be pruned at a later time.
# Clean up block refs, walking block by block
let startTick = Moment.now()
# Finalization means that we choose a single chain as the canonical one -
# it also means we're no longer interested in any branches from that chain
# up to the finalization point
let hlen = dag.heads.len
for i in 0..<hlen:
let n = hlen - i - 1
let head = dag.heads[n]
if dag.finalizedHead.blck.isAncestorOf(head):
continue
var cur = head.atSlot()
while not cur.blck.isAncestorOf(dag.finalizedHead.blck):
# Update light client data
dag.deleteLightClientData(cur.blck.bid)
dag.delState(cur) # TODO: should we move that disk I/O to `onSlotEnd`
if cur.isProposed():
dag.forkBlocks.excl(KeyedBlockRef.init(cur.blck))
dag.db.delBlock(cur.blck.root)
if cur.blck.parent.isNil:
break
cur = cur.parentOrSlot
dag.heads.del(n)
debug "Pruned the blockchain DAG",
currentCandidateHeads = dag.heads.len,
prunedHeads = hlen - dag.heads.len,
dagPruneDur = Moment.now() - startTick
iterator syncSubcommittee*(
syncCommittee: openArray[ValidatorIndex],
subcommitteeIdx: SyncSubcommitteeIndex): ValidatorIndex =
var i = subcommitteeIdx.asInt * SYNC_SUBCOMMITTEE_SIZE
let onePastEndIdx = min(syncCommittee.len, i + SYNC_SUBCOMMITTEE_SIZE)
while i < onePastEndIdx:
yield syncCommittee[i]
inc i
iterator syncSubcommitteePairs*(
syncCommittee: openArray[ValidatorIndex],
subcommitteeIdx: SyncSubcommitteeIndex): tuple[validatorIdx: ValidatorIndex,
subcommitteeIdx: int] =
var i = subcommitteeIdx.asInt * SYNC_SUBCOMMITTEE_SIZE
let onePastEndIdx = min(syncCommittee.len, i + SYNC_SUBCOMMITTEE_SIZE)
while i < onePastEndIdx:
yield (syncCommittee[i], i)
inc i
func syncCommitteeParticipants*(dag: ChainDAGRef,
slot: Slot): seq[ValidatorIndex] =
withState(dag.headState):
when stateFork >= BeaconStateFork.Altair:
let
period = sync_committee_period(slot)
curPeriod = sync_committee_period(state.data.slot)
if period == curPeriod:
@(dag.headSyncCommittees.current_sync_committee)
elif period == curPeriod + 1:
@(dag.headSyncCommittees.next_sync_committee)
else: @[]
else:
@[]
func getSubcommitteePositionsAux(
dag: ChainDAGRef,
syncCommittee: openArray[ValidatorIndex],
subcommitteeIdx: SyncSubcommitteeIndex,
validatorIdx: uint64): seq[uint64] =
var pos = 0'u64
for valIdx in syncCommittee.syncSubcommittee(subcommitteeIdx):
if validatorIdx == uint64(valIdx):
result.add pos
inc pos
func getSubcommitteePositions*(
dag: ChainDAGRef,
slot: Slot,
subcommitteeIdx: SyncSubcommitteeIndex,
validatorIdx: uint64): seq[uint64] =
withState(dag.headState):
when stateFork >= BeaconStateFork.Altair:
let
period = sync_committee_period(slot)
curPeriod = sync_committee_period(state.data.slot)
template search(syncCommittee: openArray[ValidatorIndex]): seq[uint64] =
dag.getSubcommitteePositionsAux(
syncCommittee, subcommitteeIdx, validatorIdx)
if period == curPeriod:
search(dag.headSyncCommittees.current_sync_committee)
elif period == curPeriod + 1:
search(dag.headSyncCommittees.next_sync_committee)
else: @[]
else:
@[]
template syncCommitteeParticipants*(
dag: ChainDAGRef,
slot: Slot,
subcommitteeIdx: SyncSubcommitteeIndex): seq[ValidatorIndex] =
toSeq(syncSubcommittee(dag.syncCommitteeParticipants(slot), subcommitteeIdx))
iterator syncCommitteeParticipants*(
dag: ChainDAGRef,
slot: Slot,
subcommitteeIdx: SyncSubcommitteeIndex,
aggregationBits: SyncCommitteeAggregationBits): ValidatorIndex =
for pos, valIdx in dag.syncCommitteeParticipants(slot, subcommitteeIdx):
if pos < aggregationBits.bits and aggregationBits[pos]:
yield valIdx
func needStateCachesAndForkChoicePruning*(dag: ChainDAGRef): bool =
dag.lastPrunePoint != dag.finalizedHead
proc pruneStateCachesDAG*(dag: ChainDAGRef) =
## This prunes the cached state checkpoints and EpochRef
## This does NOT prune the state associated with invalidated blocks on a fork
## They are pruned via `pruneBlocksDAG`
##
## This updates the `dag.lastPrunePoint` variable
doAssert dag.needStateCachesAndForkChoicePruning()
let startTick = Moment.now()
block: # Remove states, walking slot by slot
# We remove all state checkpoints that come _before_ the current finalized
# head, as we might frequently be asked to replay states from the
# finalized checkpoint and onwards (for example when validating blocks and
# attestations)
var
cur = dag.finalizedHead.stateCheckpoint.parentOrSlot
prev = dag.lastPrunePoint.stateCheckpoint.parentOrSlot
while cur.blck != nil and cur != prev:
if not isFinalizedStateSnapshot(cur.slot) and
cur.slot != dag.tail.slot:
dag.delState(cur)
cur = cur.parentOrSlot
let statePruneTick = Moment.now()
block: # Clean up old EpochRef instances
# After finalization, we can clear up the epoch cache and save memory -
# it will be recomputed if needed
for i in 0..<dag.epochRefs.len:
if dag.epochRefs[i] != nil and
dag.epochRefs[i].epoch < dag.finalizedHead.slot.epoch:
dag.epochRefs[i] = nil
let epochRefPruneTick = Moment.now()
dag.lastPrunePoint = dag.finalizedHead
debug "Pruned the state checkpoints and DAG caches.",
statePruneDur = statePruneTick - startTick,
epochRefPruneDur = epochRefPruneTick - statePruneTick
proc updateHead*(
dag: ChainDAGRef,
newHead: BlockRef,
quarantine: var Quarantine) =
## Update what we consider to be the current head, as given by the fork
## choice.
##
## The choice of head affects the choice of finalization point - the order
## of operations naturally becomes important here - after updating the head,
## blocks that were once considered potential candidates for a tree will
## now fall from grace, or no longer be considered resolved.
doAssert not newHead.isNil()
doAssert not newHead.parent.isNil() or newHead.slot <= dag.tail.slot
logScope:
newHead = shortLog(newHead)
if dag.head == newHead:
trace "No head block update"
return
let
lastHead = dag.head
lastHeadStateRoot = getStateRoot(dag.headState)
# Start off by making sure we have the right state - updateStateData will try
# to use existing in-memory states to make this smooth
var cache: StateCache
if not updateState(
dag, dag.headState, newHead.atSlot(), false, cache):
# Advancing the head state should never fail, given that the tail is
# implicitly finalised, the head is an ancestor of the tail and we always
# store the tail state in the database, as well as every epoch slot state in
# between
fatal "Unable to load head state during head update, database corrupt?",
lastHead = shortLog(lastHead)
quit 1
dag.head = newHead
dag.db.putHeadBlock(newHead.root)
updateBeaconMetrics(dag.headState, dag.head.bid, cache)
withState(dag.headState):
when stateFork >= BeaconStateFork.Altair:
dag.headSyncCommittees = state.data.get_sync_committee_cache(cache)
let
finalized_checkpoint =
getStateField(dag.headState, finalized_checkpoint)
finalizedSlot = max(finalized_checkpoint.epoch.start_slot(), dag.tail.slot)
finalizedHead = newHead.atSlot(finalizedSlot)
doAssert (not finalizedHead.blck.isNil),
"Block graph should always lead to a finalized block"
# Update light client data
dag.processHeadChangeForLightClient()
let (isAncestor, ancestorDepth) = lastHead.getDepth(newHead)
if not(isAncestor):
notice "Updated head block with chain reorg",
lastHead = shortLog(lastHead),
headParent = shortLog(newHead.parent),
stateRoot = shortLog(getStateRoot(dag.headState)),
headBlock = shortLog(dag.head),
stateSlot = shortLog(getStateField(dag.headState, slot)),
justified = shortLog(getStateField(
dag.headState, current_justified_checkpoint)),
finalized = shortLog(getStateField(dag.headState, finalized_checkpoint))
if not(isNil(dag.onReorgHappened)):
let data = ReorgInfoObject.init(dag.head.slot, uint64(ancestorDepth),
lastHead.root, newHead.root,
lastHeadStateRoot,
getStateRoot(dag.headState))
dag.onReorgHappened(data)
# A reasonable criterion for "reorganizations of the chain"
quarantine.clearAfterReorg()
beacon_reorgs_total_total.inc()
beacon_reorgs_total.inc()
else:
debug "Updated head block",
head = shortLog(dag.head),
stateRoot = shortLog(getStateRoot(dag.headState)),
justified = shortLog(getStateField(
dag.headState, current_justified_checkpoint)),
finalized = shortLog(getStateField(dag.headState, finalized_checkpoint))
if not(isNil(dag.onHeadChanged)):
let
currentEpoch = epoch(newHead.slot)
depRoot = withState(dag.headState): state.proposer_dependent_root
prevDepRoot = withState(dag.headState): state.attester_dependent_root
epochTransition = (finalizedHead != dag.finalizedHead)
let data = HeadChangeInfoObject.init(dag.head.slot, dag.head.root,
getStateRoot(dag.headState),
epochTransition, depRoot,
prevDepRoot)
dag.onHeadChanged(data)
withState(dag.headState):
# Every time the head changes, the "canonical" view of balances and other
# state-related metrics change - notify the validator monitor.
# Doing this update during head update ensures there's a reasonable number
# of such updates happening - at most once per valid block.
dag.validatorMonitor[].registerState(state.data)
if finalizedHead != dag.finalizedHead:
debug "Reached new finalization checkpoint",
head = shortLog(dag.head),
stateRoot = shortLog(getStateRoot(dag.headState)),
justified = shortLog(getStateField(
dag.headState, current_justified_checkpoint)),
finalized = shortLog(getStateField(dag.headState, finalized_checkpoint))
block:
# Update `dag.finalizedBlocks` with all newly finalized blocks (those
# newer than the previous finalized head), then update `dag.finalizedHead`
dag.finalizedBlocks.setLen(finalizedHead.slot - dag.tail.slot + 1)
var tmp = finalizedHead.blck
while not isNil(tmp) and tmp.slot >= dag.finalizedHead.slot:
dag.finalizedBlocks[(tmp.slot - dag.tail.slot).int] = tmp
if tmp != finalizedHead.blck:
# The newly finalized block itself should remain in here so that fork
# choice still can find it via root
dag.forkBlocks.excl(KeyedBlockRef.init(tmp))
tmp = tmp.parent
dag.finalizedHead = finalizedHead
dag.updateFinalizedBlocks()
# Pruning the block dag is required every time the finalized head changes
# in order to clear out blocks that are no longer viable and should
# therefore no longer be considered as part of the chain we're following
dag.pruneBlocksDAG()
# Update light client data
dag.processFinalizationForLightClient()
# Send notification about new finalization point via callback.
if not(isNil(dag.onFinHappened)):
let stateRoot =
if dag.finalizedHead.slot == dag.head.slot: getStateRoot(dag.headState)
elif dag.finalizedHead.slot + SLOTS_PER_HISTORICAL_ROOT > dag.head.slot:
getStateField(dag.headState, state_roots).data[
int(dag.finalizedHead.slot mod SLOTS_PER_HISTORICAL_ROOT)]
else:
Eth2Digest() # The thing that finalized was >8192 blocks old?
let data = FinalizationInfoObject.init(
dag.finalizedHead.blck.root,
stateRoot,
dag.finalizedHead.slot.epoch)
dag.onFinHappened(dag, data)
proc isInitialized*(T: type ChainDAGRef, db: BeaconChainDB): Result[void, cstring] =
# Lightweight check to see if we have the minimal information needed to
# load up a database - we don't check head here - if something is wrong with
# head, it's likely an initialized, but corrupt database - init will detect
# that
let
genesisBlockRoot = db.getGenesisBlock()
if not genesisBlockRoot.isSome():
return err("Genesis block root missing")
let
genesisBlock = db.getForkedBlock(genesisBlockRoot.get())
if not genesisBlock.isSome():
return err("Genesis block missing")
let
genesisStateRoot = withBlck(genesisBlock.get()): blck.message.state_root
if not db.containsState(genesisStateRoot):
return err("Genesis state missing")
let
tailBlockRoot = db.getTailBlock()
if not tailBlockRoot.isSome():
return err("Tail block root missing")
let
tailBlock = db.getForkedBlock(tailBlockRoot.get())
if not tailBlock.isSome():
return err("Tail block missing")
let
tailStateRoot = withBlck(tailBlock.get()): blck.message.state_root
if not db.containsState(tailStateRoot):
return err("Tail state missing")
ok()
proc preInit*(
T: type ChainDAGRef, db: BeaconChainDB,
genesisState, tailState: ForkedHashedBeaconState,
tailBlock: ForkedTrustedSignedBeaconBlock) =
# write a genesis state, the way the ChainDAGRef expects it to be stored in
# database
logScope:
genesisStateRoot = getStateRoot(genesisState)
genesisStateSlot = getStateField(genesisState, slot)
tailStateRoot = getStateRoot(tailState)
tailStateSlot = getStateField(tailState, slot)
let genesisBlockRoot = withState(genesisState):
if state.root != getStateRoot(tailState):
# Different tail and genesis
if state.data.slot >= getStateField(tailState, slot):
fatal "Tail state must be newer or the same as genesis state"
quit 1
let tail_genesis_validators_root =
getStateField(tailState, genesis_validators_root)
if state.data.genesis_validators_root != tail_genesis_validators_root:
fatal "Tail state doesn't match genesis validators root, it is likely from a different network!",
genesis_validators_root = shortLog(state.data.genesis_validators_root),
tail_genesis_validators_root = shortLog(tail_genesis_validators_root)
quit 1
let blck = get_initial_beacon_block(state)
db.putBlock(blck)
db.putState(state)
db.putGenesisBlock(blck.root)
blck.root
else: # tail and genesis are the same
withBlck(tailBlock):
db.putGenesisBlock(blck.root)
blck.root
withState(tailState):
withBlck(tailBlock):
# When looking up the state root of the tail block, we don't use the
# BlockSlot->state_root map, so the only way the init code can find the
# state is through the state root in the block - this could be relaxed
# down the line
if blck.message.state_root != state.root:
fatal "State must match the given block",
tailBlck = shortLog(blck)
quit 1
db.putBlock(blck)
db.putState(state)
db.putTailBlock(blck.root)
db.putHeadBlock(blck.root)
notice "New database from snapshot",
genesisBlockRoot = shortLog(genesisBlockRoot),
genesisStateRoot = shortLog(getStateRoot(genesisState)),
tailBlockRoot = shortLog(blck.root),
tailStateRoot = shortLog(state.root),
fork = state.data.fork,
validators = state.data.validators.len()
proc getProposer*(
dag: ChainDAGRef, head: BlockRef, slot: Slot): Option[ValidatorIndex] =
let
epochRef = block:
let tmp = dag.getEpochRef(head, slot.epoch(), false)
if tmp.isErr():
return none(ValidatorIndex)
tmp.get()
slotInEpoch = slot.since_epoch_start()
let proposer = epochRef.beacon_proposers[slotInEpoch]
if proposer.isSome():
if proposer.get().uint64 >= dag.db.immutableValidators.lenu64():
# Sanity check - it should never happen that the key cache doesn't contain
# a key for the selected proposer - that would mean that we somehow
# created validators in the state without updating the cache!
warn "Proposer key not found",
keys = dag.db.immutableValidators.lenu64(), proposer = proposer.get()
return none(ValidatorIndex)
proposer
proc aggregateAll*(
dag: ChainDAGRef,
validator_indices: openArray[ValidatorIndex]): Result[CookedPubKey, cstring] =
if validator_indices.len == 0:
# Aggregation spec requires non-empty collection
# - https://tools.ietf.org/html/draft-irtf-cfrg-bls-signature-04
# Eth2 spec requires at least one attesting index in attestation
# - https://github.com/ethereum/consensus-specs/blob/v1.1.10/specs/phase0/beacon-chain.md#is_valid_indexed_attestation
return err("aggregate: no attesting keys")
let
firstKey = dag.validatorKey(validator_indices[0])
if not firstKey.isSome():
return err("aggregate: invalid validator index")
var aggregateKey{.noinit.}: AggregatePublicKey
aggregateKey.init(firstKey.get())
for i in 1 ..< validator_indices.len:
let key = dag.validatorKey(validator_indices[i])
if not key.isSome():
return err("aggregate: invalid validator index")
aggregateKey.aggregate(key.get())
ok(finish(aggregateKey))
proc aggregateAll*(
dag: ChainDAGRef,
validator_indices: openArray[ValidatorIndex|uint64],
bits: BitSeq | BitArray): Result[CookedPubKey, cstring] =
if validator_indices.len() != bits.len():
return err("aggregateAll: mismatch in bits length")
var
aggregateKey{.noinit.}: AggregatePublicKey
inited = false
for i in 0..<bits.len():
if bits[i]:
let key = dag.validatorKey(validator_indices[i])
if not key.isSome():
return err("aggregate: invalid validator index")
if inited:
aggregateKey.aggregate(key.get)
else:
aggregateKey = AggregatePublicKey.init(key.get)
inited = true
if not inited:
err("aggregate: no attesting keys")
else:
ok(finish(aggregateKey))
func needsBackfill*(dag: ChainDAGRef): bool =
dag.backfill.slot > dag.genesis.slot
proc rebuildIndex*(dag: ChainDAGRef) =
## After a checkpoint sync, we lack intermediate states to replay from - this
## function rebuilds them so that historical replay can take place again
if dag.backfill.slot > 0:
debug "Backfill not complete, cannot rebuild archive"
return
if dag.tail.slot == dag.genesis.slot:
# The tail is the earliest slot for which we're supposed to have states -
# if it's sufficiently recent, don't do anything
debug "Archive does not need rebuilding"
return
# First, we check what states we already have in the database - that allows
# resuming the operation at any time
let
roots = dag.db.loadStateRoots()
var
canonical = newSeq[Eth2Digest](
(dag.finalizedHead.slot.epoch + EPOCHS_PER_STATE_SNAPSHOT - 1) div
EPOCHS_PER_STATE_SNAPSHOT)
# `junk` puts in place some infrastructure to prune unnecessary states - it
# will be more useful in the future as a base for pruning
junk: seq[((Slot, Eth2Digest), Eth2Digest)]
for k, v in roots:
if k[0] >= dag.finalizedHead.slot:
continue # skip newer stuff
if not isFinalizedStateSnapshot(k[0]):
# `tail` will move at the end of the process, so we won't need any
# intermediate states
junk.add((k, v))
continue # skip non-snapshot slots
if k[0] > 0:
let bs = dag.getBlockIdAtSlot(k[0] - 1)
if bs.isNone or bs.get().bid.root != k[1]:
# remove things that are no longer a canonical part of the chain or
# cannot be reached via a block
junk.add((k, v))
continue
if not dag.db.containsState(v):
continue # If it's not in the database..
canonical[k[0].epoch div EPOCHS_PER_STATE_SNAPSHOT] = v
let
state = (ref ForkedHashedBeaconState)()
var
cache: StateCache
info: ForkedEpochInfo
# `canonical` holds all slots at which a state is expected to appear, using a
# zero root whenever a particular state is missing - this way, if there's
# partial progress or gaps, they will be dealt with correctly
for i, state_root in canonical.mpairs():
if not state_root.isZero:
continue
doAssert i > 0, "Genesis should always be available"
let
startSlot = Epoch((i - 1) * EPOCHS_PER_STATE_SNAPSHOT).start_slot
slot = Epoch(i * EPOCHS_PER_STATE_SNAPSHOT).start_slot
info "Recreating state snapshot",
slot, startStateRoot = canonical[i - 1], startSlot
if getStateRoot(state[]) != canonical[i - 1]:
if not dag.db.getState(dag.cfg, startSlot, canonical[i - 1], state[], noRollback):
error "Can't load start state, database corrupt?",
startStateRoot = shortLog(canonical[i - 1]), slot = startSlot
return
for slot in startSlot..<startSlot + (EPOCHS_PER_STATE_SNAPSHOT * SLOTS_PER_EPOCH):
let bids = dag.getBlockIdAtSlot(slot).valueOr:
warn "Block id missing, cannot continue - database corrupt?", slot
return
# The slot check is needed to avoid re-applying a block
if bids.isProposed and getStateField(state[], latest_block_header).slot < bids.bid.slot:
let res = dag.applyBlock(state[], bids.bid, cache, info)
if res.isErr:
error "Failed to apply block while ", bids, slot
return
if slot.is_epoch:
cache.prune(slot.epoch)
process_slots(
dag.cfg, state[], slot, cache, info,
dag.updateFlags).expect("process_slots shouldn't fail when state slot is correct")
withState(state[]):
dag.db.putState(state)
state_root = state.root
# Now that we have states all the way to genesis, we can adjust the tail
# and readjust the in-memory indices to what they would look like if we had
# started with an earlier tail
dag.db.putTailBlock(dag.genesis.root)
var
midRef = dag.genesis
finBlocks = newSeqOfCap[BlockRef](
(dag.finalizedHead.slot.int + 1) * 3 div 2)
finBlocks.setLen(dag.finalizedHead.slot.int + 1)
finBlocks[dag.tail.slot.int..^1] = dag.finalizedBlocks
finBlocks[0] = dag.genesis
for slot, root in dag.db.finalizedBlocks:
if slot == midRef.slot:
continue
if slot == dag.tail.slot:
link(midRef, dag.tail)
break
let next = BlockRef.init(root, slot)
link(midRef, next)
midRef = next
finBlocks[midRef.slot.int] = midRef
dag.finalizedBlocks = finBlocks
dag.tail = dag.genesis
if junk.len > 0:
info "Dropping redundant states", states = junk.len
for i in junk:
dag.db.delState(i[1])