502 lines
20 KiB
Nim
502 lines
20 KiB
Nim
# beacon_chain
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# Copyright (c) 2018-2020 Status Research & Development GmbH
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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import
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# Standard library
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os, tables, strutils, times,
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# Nimble packages
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stew/[objects, bitseqs], stew/shims/macros,
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chronos, metrics, json_rpc/[rpcserver, jsonmarshal],
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chronicles,
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json_serialization/std/[options, sets, net], serialization/errors,
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eth/db/kvstore,
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eth/[keys, async_utils], eth/p2p/discoveryv5/[protocol, enr],
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# Local modules
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spec/[datatypes, digest, crypto, beaconstate, helpers, validator, network],
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conf, time, validator_pool, state_transition,
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attestation_pool, block_pool, eth2_network,
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beacon_node_common, beacon_node_types,
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mainchain_monitor, version, ssz, interop,
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attestation_aggregation, sync_manager, sszdump
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# Metrics for tracking attestation and beacon block loss
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declareCounter beacon_attestations_sent,
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"Number of beacon chain attestations sent by this peer"
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declareCounter beacon_blocks_proposed,
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"Number of beacon chain blocks sent by this peer"
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logScope: topics = "beacval"
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proc saveValidatorKey*(keyName, key: string, conf: BeaconNodeConf) =
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let validatorsDir = conf.localValidatorsDir
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let outputFile = validatorsDir / keyName
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createDir validatorsDir
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writeFile(outputFile, key)
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info "Imported validator key", file = outputFile
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template findIt(s: openarray, predicate: untyped): int =
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var res = -1
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for i, it {.inject.} in s:
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if predicate:
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res = i
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break
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res
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proc addLocalValidator*(node: BeaconNode,
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state: BeaconState,
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privKey: ValidatorPrivKey) =
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let pubKey = privKey.toPubKey()
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let idx = state.validators.asSeq.findIt(it.pubKey == pubKey)
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if idx == -1:
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# We allow adding a validator even if its key is not in the state registry:
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# it might be that the deposit for this validator has not yet been processed
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warn "Validator not in registry (yet?)", pubKey
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node.attachedValidators.addLocalValidator(pubKey, privKey)
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proc addLocalValidators*(node: BeaconNode, state: BeaconState) =
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for validatorKey in node.config.validatorKeys:
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node.addLocalValidator state, validatorKey
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info "Local validators attached ", count = node.attachedValidators.count
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func getAttachedValidator*(node: BeaconNode,
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state: BeaconState,
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idx: ValidatorIndex): AttachedValidator =
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let validatorKey = state.validators[idx].pubkey
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node.attachedValidators.getValidator(validatorKey)
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proc isSynced(node: BeaconNode, head: BlockRef): bool =
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## TODO This function is here as a placeholder for some better heurestics to
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## determine if we're in sync and should be producing blocks and
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## attestations. Generally, the problem is that slot time keeps advancing
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## even when there are no blocks being produced, so there's no way to
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## distinguish validators geniunely going missing from the node not being
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## well connected (during a network split or an internet outage for
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## example). It would generally be correct to simply keep running as if
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## we were the only legit node left alive, but then we run into issues:
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## with enough many empty slots, the validator pool is emptied leading
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## to empty committees and lots of empty slot processing that will be
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## thrown away as soon as we're synced again.
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let
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# The slot we should be at, according to the clock
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beaconTime = node.beaconClock.now()
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wallSlot = beaconTime.toSlot()
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# TODO if everyone follows this logic, the network will not recover from a
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# halt: nobody will be producing blocks because everone expects someone
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# else to do it
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if wallSlot.afterGenesis and head.slot + MaxEmptySlotCount < wallSlot.slot:
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false
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else:
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true
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proc sendAttestation(node: BeaconNode,
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fork: Fork,
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genesis_validators_root: Eth2Digest,
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validator: AttachedValidator,
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attestationData: AttestationData,
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committeeLen: int,
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indexInCommittee: int) {.async.} =
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logScope: pcs = "send_attestation"
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let validatorSignature = await validator.signAttestation(attestationData,
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fork, genesis_validators_root)
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var aggregationBits = CommitteeValidatorsBits.init(committeeLen)
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aggregationBits.setBit indexInCommittee
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var attestation = Attestation(
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data: attestationData,
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signature: validatorSignature,
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aggregation_bits: aggregationBits
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)
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# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/validator.md#broadcast-attestation
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node.network.broadcast(
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getMainnetAttestationTopic(node.forkDigest, attestationData.index),
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attestation)
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if node.config.dumpEnabled:
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dump(node.config.dumpDir, attestationData, validator.pubKey)
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info "Attestation sent",
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attestation = shortLog(attestation),
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validator = shortLog(validator),
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indexInCommittee = indexInCommittee,
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cat = "consensus"
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beacon_attestations_sent.inc()
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type
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ValidatorInfoForMakeBeaconBlockType* = enum
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viValidator
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viRandao_reveal
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ValidatorInfoForMakeBeaconBlock* = object
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case kind*: ValidatorInfoForMakeBeaconBlockType
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of viValidator: validator*: AttachedValidator
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else: randao_reveal*: ValidatorSig
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proc makeBeaconBlockForHeadAndSlot*(node: BeaconNode,
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val_info: ValidatorInfoForMakeBeaconBlock,
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validator_index: ValidatorIndex,
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graffiti: Eth2Digest,
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head: BlockRef,
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slot: Slot):
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tuple[message: Option[BeaconBlock], fork: Fork, genesis_validators_root: Eth2Digest] =
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# Advance state to the slot that we're proposing for - this is the equivalent
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# of running `process_slots` up to the slot of the new block.
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node.blockPool.withState(
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node.blockPool.tmpState, head.atSlot(slot)):
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let (eth1data, deposits) =
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if node.mainchainMonitor.isNil:
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(get_eth1data_stub(state.eth1_deposit_index, slot.compute_epoch_at_slot()),
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newSeq[Deposit]())
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else:
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node.mainchainMonitor.getBlockProposalData(state)
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# TODO perhaps just making the enclosing function accept 2 different types at the
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# same time and doing some compile-time branching logic is cleaner (without the
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# need for the discriminated union)... but we need the `state` from `withState`
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# in order to get the fork/root for the specific head/slot for the randao_reveal
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# and it's causing problems when the function becomes a generic for 2 types...
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proc getRandaoReveal(val_info: ValidatorInfoForMakeBeaconBlock): ValidatorSig =
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if val_info.kind == viValidator:
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val_info.validator.genRandaoReveal(state.fork, state.genesis_validators_root, slot)
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else:
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val_info.randao_reveal
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let
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poolPtr = unsafeAddr node.blockPool.dag # safe because restore is short-lived
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func restore(v: var HashedBeaconState) =
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# TODO address this ugly workaround - there should probably be a
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# `state_transition` that takes a `StateData` instead and updates
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# the block as well
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doAssert v.addr == addr poolPtr.tmpState.data
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poolPtr.tmpState = poolPtr.headState
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let message = makeBeaconBlock(
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hashedState,
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validator_index,
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head.root,
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getRandaoReveal(val_info),
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eth1data,
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graffiti,
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node.attestationPool.getAttestationsForBlock(state),
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deposits,
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restore)
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if message.isSome():
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# TODO this restore is needed because otherwise tmpState will be internally
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# inconsistent - it's blck will not be pointing to the block that
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# created this state - we have to reset it here before `await` to avoid
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# races.
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restore(poolPtr.tmpState.data)
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return (message, state.fork, state.genesis_validators_root)
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proc proposeBlock(node: BeaconNode,
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validator: AttachedValidator,
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validator_index: ValidatorIndex,
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head: BlockRef,
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slot: Slot): Future[BlockRef] {.async.} =
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logScope: pcs = "block_proposal"
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if head.slot >= slot:
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# We should normally not have a head newer than the slot we're proposing for
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# but this can happen if block proposal is delayed
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warn "Skipping proposal, have newer head already",
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headSlot = shortLog(head.slot),
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headBlockRoot = shortLog(head.root),
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slot = shortLog(slot),
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cat = "fastforward"
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return head
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let valInfo = ValidatorInfoForMakeBeaconBlock(kind: viValidator, validator: validator)
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let beaconBlockTuple = makeBeaconBlockForHeadAndSlot(node, valInfo, validator_index, Eth2Digest(), head, slot)
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if not beaconBlockTuple.message.isSome():
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return head # already logged elsewhere!
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var
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newBlock = SignedBeaconBlock(
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message: beaconBlockTuple.message.get()
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)
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let blockRoot = hash_tree_root(newBlock.message)
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newBlock.signature = await validator.signBlockProposal(
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beaconBlockTuple.fork, beaconBlockTuple.genesis_validators_root, slot, blockRoot)
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let newBlockRef = node.blockPool.add(blockRoot, newBlock)
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if newBlockRef.isErr:
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warn "Unable to add proposed block to block pool",
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newBlock = shortLog(newBlock.message),
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blockRoot = shortLog(blockRoot),
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cat = "bug"
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return head
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info "Block proposed",
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blck = shortLog(newBlock.message),
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blockRoot = shortLog(newBlockRef[].root),
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validator = shortLog(validator),
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cat = "consensus"
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if node.config.dumpEnabled:
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dump(node.config.dumpDir, newBlock, newBlockRef[])
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node.blockPool.withState(
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node.blockPool.tmpState, newBlockRef[].atSlot(newBlockRef[].slot)):
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dump(node.config.dumpDir, hashedState, newBlockRef[])
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node.network.broadcast(node.topicBeaconBlocks, newBlock)
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beacon_blocks_proposed.inc()
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return newBlockRef[]
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proc handleAttestations(node: BeaconNode, head: BlockRef, slot: Slot) =
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## Perform all attestations that the validators attached to this node should
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## perform during the given slot
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logScope: pcs = "on_attestation"
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if slot + SLOTS_PER_EPOCH < head.slot:
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# The latest block we know about is a lot newer than the slot we're being
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# asked to attest to - this makes it unlikely that it will be included
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# at all.
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# TODO the oldest attestations allowed are those that are older than the
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# finalized epoch.. also, it seems that posting very old attestations
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# is risky from a slashing perspective. More work is needed here.
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notice "Skipping attestation, head is too recent",
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headSlot = shortLog(head.slot),
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slot = shortLog(slot)
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return
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let attestationHead = head.atSlot(slot)
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if head != attestationHead.blck:
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# In rare cases, such as when we're busy syncing or just slow, we'll be
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# attesting to a past state - we must then recreate the world as it looked
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# like back then
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notice "Attesting to a state in the past, falling behind?",
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headSlot = shortLog(head.slot),
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attestationHeadSlot = shortLog(attestationHead.slot),
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attestationSlot = shortLog(slot)
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trace "Checking attestations",
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attestationHeadRoot = shortLog(attestationHead.blck.root),
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attestationSlot = shortLog(slot),
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cat = "attestation"
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# Collect data to send before node.stateCache grows stale
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var attestations: seq[tuple[
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data: AttestationData, committeeLen, indexInCommittee: int,
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validator: AttachedValidator]]
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# We need to run attestations exactly for the slot that we're attesting to.
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# In case blocks went missing, this means advancing past the latest block
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# using empty slots as fillers.
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# https://github.com/ethereum/eth2.0-specs/blob/v0.8.4/specs/validator/0_beacon-chain-validator.md#validator-assignments
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# TODO we could cache the validator assignment since it's valid for the entire
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# epoch since it doesn't change, but that has to be weighed against
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# the complexity of handling forks correctly - instead, we use an adapted
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# version here that calculates the committee for a single slot only
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node.blockPool.withState(node.blockPool.tmpState, attestationHead):
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var cache = get_empty_per_epoch_cache()
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let committees_per_slot = get_committee_count_at_slot(state, slot)
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for committee_index in 0'u64..<committees_per_slot:
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let committee = get_beacon_committee(
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state, slot, committee_index.CommitteeIndex, cache)
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for index_in_committee, validatorIdx in committee:
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let validator = node.getAttachedValidator(state, validatorIdx)
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if validator != nil:
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let ad = makeAttestationData(state, slot, committee_index, blck.root)
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attestations.add((ad, committee.len, index_in_committee, validator))
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for a in attestations:
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traceAsyncErrors sendAttestation(
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node, state.fork, state.genesis_validators_root, a.validator, a.data,
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a.committeeLen, a.indexInCommittee)
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proc handleProposal(node: BeaconNode, head: BlockRef, slot: Slot):
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Future[BlockRef] {.async.} =
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## Perform the proposal for the given slot, iff we have a validator attached
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## that is supposed to do so, given the shuffling in head
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# TODO here we advance the state to the new slot, but later we'll be
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# proposing for it - basically, we're selecting proposer based on an
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# empty slot
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let proposer = node.blockPool.getProposer(head, slot)
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if proposer.isNone():
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return head
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let validator = node.attachedValidators.getValidator(proposer.get()[1])
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if validator != nil:
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return await proposeBlock(node, validator, proposer.get()[0], head, slot)
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debug "Expecting block proposal",
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headRoot = shortLog(head.root),
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slot = shortLog(slot),
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proposer_index = proposer.get()[0],
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proposer = shortLog(proposer.get()[1]),
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cat = "consensus",
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pcs = "wait_for_proposal"
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return head
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proc broadcastAggregatedAttestations(
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node: BeaconNode, aggregationHead: BlockRef, aggregationSlot: Slot,
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trailing_distance: uint64) =
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# The index is via a
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# locally attested validator. Unlike in handleAttestations(...) there's a
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# single one at most per slot (because that's how aggregation attestation
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# works), so the machinery that has to handle looping across, basically a
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# set of locally attached validators is in principle not necessary, but a
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# way to organize this. Then the private key for that validator should be
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# the corresponding one -- whatver they are, they match.
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let bs = BlockSlot(blck: aggregationHead, slot: aggregationSlot)
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node.blockPool.withState(node.blockPool.tmpState, bs):
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let
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committees_per_slot = get_committee_count_at_slot(state, aggregationSlot)
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var cache = get_empty_per_epoch_cache()
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for committee_index in 0'u64..<committees_per_slot:
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let committee = get_beacon_committee(
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state, aggregationSlot, committee_index.CommitteeIndex, cache)
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for index_in_committee, validatorIdx in committee:
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let validator = node.getAttachedValidator(state, validatorIdx)
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if validator != nil:
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# This is slightly strange/inverted control flow, since really it's
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# going to happen once per slot, but this is the best way to get at
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# the validator index and private key pair. TODO verify it only has
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# one isSome() with test.
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let aggregateAndProof =
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aggregate_attestations(node.attestationPool, state,
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committee_index.CommitteeIndex,
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# TODO https://github.com/status-im/nim-beacon-chain/issues/545
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# this assumes in-process private keys
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validator.privKey,
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trailing_distance)
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# Don't broadcast when, e.g., this node isn't an aggregator
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if aggregateAndProof.isSome:
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var signedAP = SignedAggregateAndProof(
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message: aggregateAndProof.get,
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# TODO Make the signing async here
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signature: validator.signAggregateAndProof(
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aggregateAndProof.get, state.fork,
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state.genesis_validators_root))
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node.network.broadcast(node.topicAggregateAndProofs, signedAP)
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proc handleValidatorDuties*(
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node: BeaconNode, head: BlockRef, lastSlot, slot: Slot): Future[BlockRef] {.async.} =
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## Perform validator duties - create blocks, vote and aggreagte existing votes
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if node.attachedValidators.count == 0:
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# Nothing to do because we have no validator attached
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return head
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if not node.isSynced(head):
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notice "Node out of sync, skipping validator duties",
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slot, headSlot = head.slot
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return head
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var curSlot = lastSlot + 1
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var head = head
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# Start by checking if there's work we should have done in the past that we
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# can still meaningfully do
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while curSlot < slot:
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# TODO maybe even collect all work synchronously to avoid unnecessary
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# state rewinds while waiting for async operations like validator
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# signature..
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notice "Catching up",
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curSlot = shortLog(curSlot),
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lastSlot = shortLog(lastSlot),
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slot = shortLog(slot),
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cat = "overload"
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# For every slot we're catching up, we'll propose then send
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# attestations - head should normally be advancing along the same branch
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# in this case
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# TODO what if we receive blocks / attestations while doing this work?
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head = await handleProposal(node, head, curSlot)
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# For each slot we missed, we need to send out attestations - if we were
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# proposing during this time, we'll use the newly proposed head, else just
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# keep reusing the same - the attestation that goes out will actually
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# rewind the state to what it looked like at the time of that slot
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# TODO smells like there's an optimization opportunity here
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handleAttestations(node, head, curSlot)
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curSlot += 1
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head = await handleProposal(node, head, slot)
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# We've been doing lots of work up until now which took time. Normally, we
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# send out attestations at the slot thirds-point, so we go back to the clock
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# to see how much time we need to wait.
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# TODO the beacon clock might jump here also. It's probably easier to complete
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# the work for the whole slot using a monotonic clock instead, then deal
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# with any clock discrepancies once only, at the start of slot timer
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# processing..
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# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/validator.md#attesting
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# A validator should create and broadcast the attestation to the associated
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# attestation subnet when either (a) the validator has received a valid
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# block from the expected block proposer for the assigned slot or
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# (b) one-third of the slot has transpired (`SECONDS_PER_SLOT / 3` seconds
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# after the start of slot) -- whichever comes first.
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template sleepToSlotOffset(extra: chronos.Duration, msg: static string) =
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let
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fromNow = node.beaconClock.fromNow(slot.toBeaconTime(extra))
|
|
|
|
if fromNow.inFuture:
|
|
trace msg,
|
|
slot = shortLog(slot),
|
|
fromNow = shortLog(fromNow.offset),
|
|
cat = "scheduling"
|
|
|
|
await sleepAsync(fromNow.offset)
|
|
|
|
# Time passed - we might need to select a new head in that case
|
|
head = node.updateHead()
|
|
|
|
sleepToSlotOffset(
|
|
seconds(int64(SECONDS_PER_SLOT)) div 3, "Waiting to send attestations")
|
|
|
|
handleAttestations(node, head, slot)
|
|
|
|
# https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/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:
|
|
sleepToSlotOffset(
|
|
seconds(int64(SECONDS_PER_SLOT * 2) div 3),
|
|
"Waiting to aggregate attestations")
|
|
|
|
const TRAILING_DISTANCE = 1
|
|
let
|
|
aggregationSlot = slot - TRAILING_DISTANCE
|
|
aggregationHead = getAncestorAt(head, aggregationSlot)
|
|
|
|
broadcastAggregatedAttestations(
|
|
node, aggregationHead, aggregationSlot, TRAILING_DISTANCE)
|
|
|
|
return head
|