import deques, tables, hashes, options, strformat, chronos, web3, web3/ethtypes, json, chronicles, eth/async_utils, spec/[datatypes, digest, crypto, beaconstate, helpers], merkle_minimal from times import epochTime export ethtypes contract(DepositContract): proc deposit(pubkey: Bytes48, withdrawalCredentials: Bytes32, signature: Bytes96, deposit_data_root: FixedBytes[32]) proc get_deposit_root(): FixedBytes[32] proc get_deposit_count(): Bytes8 proc DepositEvent(pubkey: Bytes48, withdrawalCredentials: Bytes32, amount: Bytes8, signature: Bytes96, index: Bytes8) {.event.} # TODO # The raises list of this module are still not usable due to general # Exceptions being reported from Chronos's asyncfutures2. type Eth1BlockNumber* = uint64 Eth1BlockTimestamp* = uint64 Eth1Block* = ref object number*: Eth1BlockNumber timestamp*: Eth1BlockTimestamp deposits*: seq[Deposit] voteData*: Eth1Data knownGoodDepositsCount*: Option[uint64] Eth1Chain* = object knownStart: Eth1Data knownStartBlockNum: Option[Eth1BlockNumber] blocks: Deque[Eth1Block] blocksByHash: Table[BlockHash, Eth1Block] allDeposits*: seq[Deposit] MainchainMonitor* = ref object depositContractAddress: Address dataProviderFactory*: DataProviderFactory genesisState: NilableBeaconStateRef genesisStateFut: Future[void] genesisMonitoringFut: Future[void] eth1Chain: Eth1Chain depositQueue: AsyncQueue[BlockHeader] runFut: Future[void] DataProvider* = object of RootObj DataProviderRef* = ref DataProvider DataProviderFactory* = object desc: string new: proc(depositContractAddress: Address): Future[DataProviderRef] {. gcsafe # raises: [Defect] .} Web3DataProvider* = object of DataProvider url: string web3: Web3 ns: Sender[DepositContract] blockHeadersSubscription: Subscription Web3DataProviderRef* = ref Web3DataProvider ReorgDepthLimitExceeded = object of CatchableError CorruptDataProvider = object of CatchableError DisconnectHandler* = proc () {.gcsafe, raises: [Defect].} DepositEventHandler* = proc ( pubkey: Bytes48, withdrawalCredentials: Bytes32, amount: Bytes8, signature: Bytes96, merkleTreeIndex: Bytes8, j: JsonNode) {.raises: [Defect], gcsafe.} const reorgDepthLimit = 1000 web3Timeouts = 5.seconds followDistanceInSeconds = uint64(SECONDS_PER_ETH1_BLOCK * ETH1_FOLLOW_DISTANCE) totalDepositsNeededForGenesis = uint64 max(SLOTS_PER_EPOCH, MIN_GENESIS_ACTIVE_VALIDATOR_COUNT) # TODO Nim's analysis on the lock level of the methods in this # module seems broken. Investigate and file this as an issue. {.push warning[LockLevel]: off.} static: # https://github.com/ethereum/eth2.0-specs/blob/v0.12.1/specs/phase0/beacon-chain.md#genesis when SPEC_VERSION == "0.12.1": doAssert SECONDS_PER_ETH1_BLOCK * ETH1_FOLLOW_DISTANCE < GENESIS_DELAY, "Invalid configuration: GENESIS_DELAY is set too low" # https://github.com/ethereum/eth2.0-specs/blob/v0.12.1/specs/phase0/validator.md#get_eth1_data func compute_time_at_slot(state: BeaconState, slot: Slot): uint64 = state.genesis_time + slot * SECONDS_PER_SLOT # https://github.com/ethereum/eth2.0-specs/blob/v0.12.1/specs/phase0/validator.md#get_eth1_data func voting_period_start_time*(state: BeaconState): uint64 = let eth1_voting_period_start_slot = state.slot - state.slot mod SLOTS_PER_ETH1_VOTING_PERIOD.uint64 compute_time_at_slot(state, eth1_voting_period_start_slot) # https://github.com/ethereum/eth2.0-specs/blob/v0.12.1/specs/phase0/validator.md#get_eth1_data func is_candidate_block(blk: Eth1Block, period_start: uint64): bool = (blk.timestamp + SECONDS_PER_ETH1_BLOCK.uint64 * ETH1_FOLLOW_DISTANCE.uint64 <= period_start) and (blk.timestamp + SECONDS_PER_ETH1_BLOCK.uint64 * ETH1_FOLLOW_DISTANCE.uint64 * 2 >= period_start) func asEth2Digest*(x: BlockHash): Eth2Digest = Eth2Digest(data: array[32, byte](x)) template asBlockHash(x: Eth2Digest): BlockHash = BlockHash(x.data) func shortLog(b: Eth1Block): string = &"{b.number}:{shortLog b.voteData.block_hash}" func getDepositsInRange(eth1Chain: Eth1Chain, sinceBlock, latestBlock: Eth1BlockNumber): seq[Deposit] = ## Returns all deposits that happened AFTER the block `sinceBlock` (not inclusive). ## The deposits in `latestBlock` will be included. if latestBlock <= sinceBlock: return let firstBlockInCache = eth1Chain.blocks[0].number # This function should be used with indices obtained with `eth1Chain.findBlock`. # This guarantess that both of these indices will be valid: doAssert sinceBlock >= firstBlockInCache and int(latestBlock - firstBlockInCache) < eth1Chain.blocks.len let sinceBlockIdx = sinceBlock - firstBlockInCache latestBlockIdx = latestBlock - firstBlockInCache for i in (sinceBlockIdx + 1) ..< latestBlockIdx: result.add eth1Chain.blocks[i].deposits template findBlock*(eth1Chain: Eth1Chain, hash: BlockHash): Eth1Block = eth1Chain.blocksByHash.getOrDefault(hash, nil) template findBlock*(eth1Chain: Eth1Chain, eth1Data: Eth1Data): Eth1Block = getOrDefault(eth1Chain.blocksByHash, asBlockHash(eth1Data.block_hash), nil) proc findParent*(eth1Chain: Eth1Chain, blk: BlockObject): Eth1Block = result = eth1Chain.findBlock(blk.parentHash) # a distinct type is stipped here: let blockNumber = Eth1BlockNumber(blk.number) if result != nil and result.number != blockNumber - 1: debug "Found inconsistent numbering of Eth1 blocks. Ignoring block.", blockHash = blk.hash.toHex, blockNumber, parentHash = blk.parentHash.toHex, parentNumber = result.number result = nil func latestCandidateBlock(eth1Chain: Eth1Chain, periodStart: uint64): Eth1Block = for i in countdown(eth1Chain.blocks.len - 1, 0): let blk = eth1Chain.blocks[i] if is_candidate_block(blk, periodStart): return blk func popBlock(eth1Chain: var Eth1Chain) = let removed = eth1Chain.blocks.popLast eth1Chain.blocksByHash.del removed.voteData.block_hash.asBlockHash func trimHeight(eth1Chain: var Eth1Chain, blockNumber: Eth1BlockNumber) = ## Removes all blocks above certain `blockNumber` while eth1Chain.blocks.len > 0: if eth1Chain.blocks.peekLast.number > blockNumber: eth1Chain.popBlock() else: break if eth1Chain.blocks.len > 0: eth1Chain.allDeposits.setLen(eth1Chain.blocks[^1].voteData.deposit_count) else: eth1Chain.allDeposits.setLen(0) func isSuccessorBlock(eth1Chain: Eth1Chain, newBlock: Eth1Block): bool = let currentDepositCount = if eth1Chain.blocks.len == 0: eth1Chain.knownStart.deposit_count else: let lastBlock = eth1Chain.blocks.peekLast if lastBlock.number >= newBlock.number: return false lastBlock.voteData.deposit_count (currentDepositCount + newBlock.deposits.len.uint64) == newBlock.voteData.deposit_count func addSuccessorBlock*(eth1Chain: var Eth1Chain, newBlock: Eth1Block): bool = result = isSuccessorBlock(eth1Chain, newBlock) if result: eth1Chain.allDeposits.add newBlock.deposits reset newBlock.deposits eth1Chain.blocks.addLast newBlock eth1Chain.blocksByHash[newBlock.voteData.block_hash.asBlockHash] = newBlock func totalDeposits*(eth1Chain: Eth1Chain): int = for blk in eth1Chain.blocks: result += blk.deposits.len func allDeposits*(eth1Chain: Eth1Chain): seq[Deposit] = for blk in eth1Chain.blocks: result.add blk.deposits func clear*(eth1Chain: var Eth1Chain) = eth1Chain = default(Eth1Chain) template hash*(x: Eth1Block): Hash = hash(x.voteData.block_hash.data) template notImplemented = doAssert false, "Method not implemented" method getBlockByHash*(p: DataProviderRef, hash: BlockHash): Future[BlockObject] {. base gcsafe locks: 0 # raises: [Defect] .} = notImplemented method getBlockByNumber*(p: DataProviderRef, hash: Eth1BlockNumber): Future[BlockObject] {. base gcsafe locks: 0 # raises: [Defect] .} = notImplemented method onDisconnect*(p: DataProviderRef, handler: DisconnectHandler) {. base gcsafe locks: 0 # raises: [] .} = notImplemented method onBlockHeaders*(p: DataProviderRef, blockHeaderHandler: BlockHeaderHandler, errorHandler: SubscriptionErrorHandler): Future[void] {. base gcsafe locks: 0 # raises: [] .} = notImplemented method close*(p: DataProviderRef): Future[void] {. base gcsafe locks: 0 # raises: [Defect] .} = notImplemented method fetchDepositData*(p: DataProviderRef, fromBlock, toBlock: Eth1BlockNumber): Future[seq[Eth1Block]] {. base gcsafe locks: 0 # raises: [Defect, CatchableError] .} = notImplemented method fetchBlockDetails(p: DataProviderRef, blk: Eth1Block): Future[void] {. base gcsafe locks: 0 # raises: [Defect, CatchableError] .} = notImplemented proc new*(T: type Web3DataProvider, web3Url: string, depositContractAddress: Address): Future[ref Web3DataProvider] {. async # raises: [Defect] .} = try: type R = ref T let web3 = await newWeb3(web3Url) ns = web3.contractSender(DepositContract, depositContractAddress) return R(url: web3Url, web3: web3, ns: ns) except CatchableError: return nil func web3Provider*(web3Url: string): DataProviderFactory = proc factory(depositContractAddress: Address): Future[DataProviderRef] {.async.} = result = await Web3DataProvider.new(web3Url, depositContractAddress) DataProviderFactory(desc: "web3(" & web3Url & ")", new: factory) method close*(p: Web3DataProviderRef): Future[void] {.async, locks: 0.} = if p.blockHeadersSubscription != nil: await p.blockHeadersSubscription.unsubscribe() await p.web3.close() method getBlockByHash*(p: Web3DataProviderRef, hash: BlockHash): Future[BlockObject] = return p.web3.provider.eth_getBlockByHash(hash, false) method getBlockByNumber*(p: Web3DataProviderRef, number: Eth1BlockNumber): Future[BlockObject] = return p.web3.provider.eth_getBlockByNumber(&"0x{number:X}", false) proc getBlockNumber(p: DataProviderRef, hash: BlockHash): Future[Eth1BlockNumber] {.async.} = try: let blk = awaitWithTimeout(p.getBlockByHash(hash), web3Timeouts): return 0 return Eth1BlockNumber(blk.number) except CatchableError as exc: notice "Failed to get Eth1 block number from hash", hash = $hash, err = exc.msg raise template readJsonField(j: JsonNode, fieldName: string, ValueType: type): untyped = var res: ValueType fromJson(j[fieldName], fieldName, res) res proc readJsonDeposits(depositsList: JsonNode): seq[Eth1Block] = if depositsList.kind != JArray: raise newException(CatchableError, "Web3 provider didn't return a list of deposit events") var lastEth1Block: Eth1Block for logEvent in depositsList: let blockNumber = Eth1BlockNumber readJsonField(logEvent, "blockNumber", Quantity) blockHash = readJsonField(logEvent, "blockHash", BlockHash) logData = strip0xPrefix(logEvent["data"].getStr) if lastEth1Block == nil or lastEth1Block.number != blockNumber: lastEth1Block = Eth1Block( number: blockNumber, voteData: Eth1Data(block_hash: blockHash.asEth2Digest)) result.add lastEth1Block var pubkey: Bytes48 withdrawalCredentials: Bytes32 amount: Bytes8 signature: Bytes96 index: Bytes8 var offset = 0 offset += decode(logData, offset, pubkey) offset += decode(logData, offset, withdrawalCredentials) offset += decode(logData, offset, amount) offset += decode(logData, offset, signature) offset += decode(logData, offset, index) lastEth1Block.deposits.add Deposit( data: DepositData( pubkey: ValidatorPubKey.init(array[48, byte](pubkey)), withdrawal_credentials: Eth2Digest(data: array[32, byte](withdrawalCredentials)), amount: bytes_to_int(array[8, byte](amount)), signature: ValidatorSig.init(array[96, byte](signature)))) method fetchDepositData*(p: Web3DataProviderRef, fromBlock, toBlock: Eth1BlockNumber): Future[seq[Eth1Block]] {.async, locks: 0.} = info "Obtaining deposit log events", fromBlock, toBlock return readJsonDeposits(await p.ns.getJsonLogs(DepositEvent, fromBlock = some blockId(fromBlock), toBlock = some blockId(toBlock))) method fetchBlockDetails(p: Web3DataProviderRef, blk: Eth1Block) {.async.} = let web3Block = p.getBlockByNumber(blk.number) depositRoot = p.ns.get_deposit_root.call(blockNumber = blk.number) rawCount = p.ns.get_deposit_count.call(blockNumber = blk.number) discard await web3Block discard await depositRoot discard await rawCount let depositCount = bytes_to_int(array[8, byte](rawCount.read)) blk.timestamp = Eth1BlockTimestamp(web3Block.read.timestamp) blk.voteData.deposit_count = depositCount blk.voteData.deposit_root = depositRoot.read.asEth2Digest method onDisconnect*(p: Web3DataProviderRef, handler: DisconnectHandler) {. gcsafe locks: 0 # raises: [] .} = p.web3.onDisconnect = handler method onBlockHeaders*(p: Web3DataProviderRef, blockHeaderHandler: BlockHeaderHandler, errorHandler: SubscriptionErrorHandler): Future[void] {. async gcsafe locks: 0 # raises: [] .} = if p.blockHeadersSubscription != nil: await p.blockHeadersSubscription.unsubscribe() info "Waiting for new Eth1 block headers" let options = newJObject() p.blockHeadersSubscription = await p.web3.subscribeForBlockHeaders( options, blockHeaderHandler, errorHandler) # https://github.com/ethereum/eth2.0-specs/blob/v0.11.1/specs/phase0/validator.md#get_eth1_data func getBlockProposalData*(eth1Chain: Eth1Chain, state: BeaconState): (Eth1Data, seq[Deposit]) = template voteForNoChange() = return (state.eth1_data, newSeq[Deposit]()) let prevBlock = eth1Chain.findBlock(state.eth1_data) if prevBlock == nil: # The Eth1 block currently referenced in the BeaconState is unknown to us. # This situation is not specifically covered in the honest validator spec, # but there is a similar condition where none of the eth1_data_votes is # present in our worldview. The suggestion there is to vote for "no change" # and we'll do the same here: voteForNoChange() let periodStart = voting_period_start_time(state) var otherVotesCountTable = initCountTable[Eth1Block]() for vote in state.eth1_data_votes: let eth1Block = eth1Chain.findBlock(vote) if eth1Block != nil and is_candidate_block(eth1Block, periodStart): otherVotesCountTable.inc eth1Block var ourVote: Eth1Block if otherVotesCountTable.len > 0: ourVote = otherVotesCountTable.largest.key else: ourVote = eth1Chain.latestCandidateBlock(periodStart) if ourVote == nil: voteForNoChange() (ourVote.voteData, eth1Chain.getDepositsInRange(prevBlock.number, ourVote.number)) template getBlockProposalData*(m: MainchainMonitor, state: BeaconState): untyped = getBlockProposalData(m.eth1Chain, state) proc init*(T: type MainchainMonitor, dataProviderFactory: DataProviderFactory, depositContractAddress: string, startPosition: Eth1Data): T = T(depositQueue: newAsyncQueue[BlockHeader](), dataProviderFactory: dataProviderFactory, depositContractAddress: Address.fromHex(depositContractAddress), eth1Chain: Eth1Chain(knownStart: startPosition)) proc isCandidateForGenesis(timeNow: float, blk: Eth1Block): bool = if float(blk.timestamp + followDistanceInSeconds) > timeNow: return false if genesis_time_from_eth1_timestamp(blk.timestamp) < MIN_GENESIS_TIME: return false if blk.knownGoodDepositsCount.isSome: blk.knownGoodDepositsCount.get >= totalDepositsNeededForGenesis else: blk.voteData.deposit_count >= totalDepositsNeededForGenesis proc minGenesisCandidateBlockIdx(eth1Chain: Eth1Chain): Option[int] {.raises: [Defect].} = if eth1Chain.blocks.len == 0: return let now = epochTime() if not isCandidateForGenesis(now, eth1Chain.blocks.peekLast): return var candidatePos = eth1Chain.blocks.len - 1 while candidatePos > 1: if not isCandidateForGenesis(now, eth1Chain.blocks[candidatePos - 1]): break dec candidatePos return some(candidatePos) proc createBeaconStateAux(eth1Block: Eth1Block, deposits: var openarray[Deposit]): BeaconStateRef = attachMerkleProofs deposits result = initialize_beacon_state_from_eth1(eth1Block.voteData.block_hash, eth1Block.timestamp.uint64, deposits, {}) let activeValidators = get_active_validator_indices(result[], GENESIS_EPOCH) eth1Block.knownGoodDepositsCount = some len(activeValidators).uint64 proc createBeaconState(eth1Chain: var Eth1Chain, eth1Block: Eth1Block): BeaconStateRef = createBeaconStateAux( eth1Block, eth1Chain.allDeposits.toOpenArray(0, int(eth1Block.voteData.deposit_count - 1))) proc signalGenesis(m: MainchainMonitor, genesisState: BeaconStateRef) = m.genesisState = genesisState if not m.genesisStateFut.isNil: m.genesisStateFut.complete() m.genesisStateFut = nil proc findGenesisBlockInRange(m: MainchainMonitor, startBlock, endBlock: Eth1Block): Future[Eth1Block] {.async.} = let dataProvider = await m.dataProviderFactory.new(m.depositContractAddress) if dataProvider == nil: error "Failed to initialize Eth1 data provider", provider = m.dataProviderFactory.desc raise newException(CatchableError, "Failed to initialize Eth1 data provider") var startBlock = startBlock endBlock = endBlock depositData = startBlock.voteData while startBlock.number + 1 < endBlock.number: let startBlockTime = genesis_time_from_eth1_timestamp(startBlock.timestamp) secondsPerBlock = float(endBlock.timestamp - startBlock.timestamp) / float(endBlock.number - startBlock.number) blocksToJump = max(float(MIN_GENESIS_TIME - startBlockTime) / secondsPerBlock, 1.0) candidateNumber = min(endBlock.number - 1, startBlock.number + blocksToJump.uint64) candidateBlock = await dataProvider.getBlockByNumber(candidateNumber) var candidateAsEth1Block = Eth1Block(number: candidateBlock.number.uint64, timestamp: candidateBlock.timestamp.uint64, voteData: depositData) candidateAsEth1Block.voteData.block_hash = candidateBlock.hash.asEth2Digest info "Probing possible genesis block", `block` = candidateBlock.number.uint64, timestamp = genesis_time_from_eth1_timestamp(candidateBlock.timestamp.uint64) if genesis_time_from_eth1_timestamp(candidateBlock.timestamp.uint64) < MIN_GENESIS_TIME: startBlock = candidateAsEth1Block else: endBlock = candidateAsEth1Block return endBlock proc checkForGenesisLoop(m: MainchainMonitor) {.async.} = while true: if not m.genesisState.isNil: return try: let genesisCandidateIdx = m.eth1Chain.minGenesisCandidateBlockIdx if genesisCandidateIdx.isSome: let genesisCandidateIdx = genesisCandidateIdx.get genesisCandidate = m.eth1Chain.blocks[genesisCandidateIdx] candidateState = m.eth1Chain.createBeaconState(genesisCandidate) if genesisCandidate.knownGoodDepositsCount.get >= totalDepositsNeededForGenesis: # We have a candidate state on our hands, but our current Eth1Chain # may consist only of blocks that have deposits attached to them # while the real genesis may have happened in a block without any # deposits (triggered by MIN_GENESIS_TIME). # # This can happen when the beacon node is launched after the genesis # event. We take a short cut when constructing the initial Eth1Chain # by downloading only deposit log entries. Thus, we'll see all the # blocks with deposits, but not the regular blocks in between. # # We'll handle this special case below by examing whether we are in # this potential scenario and we'll use a fast guessing algorith to # discover the ETh1 block with minimal valid genesis time. if genesisCandidateIdx > 0: let preceedingEth1Block = m.eth1Chain.blocks[genesisCandidateIdx - 1] if preceedingEth1Block.voteData.deposit_root == genesisCandidate.voteData.deposit_root: preceedingEth1Block.knownGoodDepositsCount = genesisCandidate.knownGoodDepositsCount else: discard m.eth1Chain.createBeaconState(preceedingEth1Block) if preceedingEth1Block.knownGoodDepositsCount.get >= totalDepositsNeededForGenesis and genesisCandidate.number - preceedingEth1Block.number > 1: let genesisBlock = await m.findGenesisBlockInRange(preceedingEth1Block, genesisCandidate) if genesisBlock.number != genesisCandidate.number: m.signalGenesis m.eth1Chain.createBeaconState(genesisBlock) return m.signalGenesis candidateState return else: info "Eth2 genesis candidate block rejected", `block` = shortLog(genesisCandidate), validDeposits = genesisCandidate.knownGoodDepositsCount.get, needed = totalDepositsNeededForGenesis else: # TODO: check for a stale monitor discard except CatchableError as err: debug "Unexpected error in checkForGenesisLoop", err = err.msg await sleepAsync(1.seconds) proc waitGenesis*(m: MainchainMonitor): Future[BeaconStateRef] {.async.} = if m.genesisState.isNil: if m.genesisStateFut.isNil: m.genesisStateFut = newFuture[void]("waitGenesis") m.genesisMonitoringFut = m.checkForGenesisLoop() await m.genesisStateFut m.genesisStateFut = nil if m.genesisState != nil: return m.genesisState else: result = new BeaconStateRef # make the compiler happy raiseAssert "Unreachable code" func totalNonFinalizedBlocks(eth1Chain: Eth1Chain): Natural = # TODO: implement this precisely eth1Chain.blocks.len func latestEth1Data(eth1Chain: Eth1Chain): Eth1Data = if eth1Chain.blocks.len > 0: eth1Chain.blocks[^1].voteData else: eth1Chain.knownStart func knownInvalidDepositsCount(eth1Chain: Eth1Chain): uint64 = for i in countdown(eth1Chain.blocks.len - 1, 0): let blk = eth1Chain.blocks[i] if blk.knownGoodDepositsCount.isSome: return blk.voteData.deposit_count - blk.knownGoodDepositsCount.get return 0 func maxValidDeposits(eth1Chain: Eth1Chain): uint64 = if eth1Chain.blocks.len > 0: let lastBlock = eth1Chain.blocks[^1] lastBlock.knownGoodDepositsCount.get( lastBlock.voteData.deposit_count - eth1Chain.knownInvalidDepositsCount) else: 0 proc processDeposits(m: MainchainMonitor, dataProvider: DataProviderRef) {.async.} = # ATTENTION! # Please note that this code is using a queue to guarantee the # strict serial order of processing of deposits. If we had the # same code embedded in the deposit contracts events handler, # it could easily re-order the steps due to the intruptable # interleaved execution of async code. while true: let blk = await m.depositQueue.popFirst() m.eth1Chain.trimHeight(Eth1BlockNumber(blk.number) - 1) let latestKnownBlock = if m.eth1Chain.blocks.len > 0: m.eth1Chain.blocks[^1].number elif m.eth1Chain.knownStartBlockNum.isSome: m.eth1Chain.knownStartBlockNum.get else: m.eth1Chain.knownStartBlockNum = some( await dataProvider.getBlockNumber(m.eth1Chain.knownStart.block_hash.asBlockHash)) m.eth1Chain.knownStartBlockNum.get let eth1Blocks = await dataProvider.fetchDepositData(latestKnownBlock + 1, Eth1BlockNumber blk.number) if eth1Blocks.len == 0: if m.eth1Chain.maxValidDeposits > totalDepositsNeededForGenesis and m.eth1Chain.knownStart.deposit_count == 0: let latestEth1Data = m.eth1Chain.latestEth1Data for missingBlockNum in latestKnownBlock + 1 ..< Eth1BlockNumber(blk.number): let missingBlock = await dataProvider.getBlockByNumber(missingBlockNum) doAssert m.eth1Chain.addSuccessorBlock Eth1Block( number: Eth1BlockNumber(missingBlock.number), timestamp: Eth1BlockTimestamp(missingBlock.timestamp), voteData: latestEth1Data) doAssert m.eth1Chain.addSuccessorBlock Eth1Block( number: Eth1BlockNumber(blk.number), timestamp: Eth1BlockTimestamp(blk.timestamp), voteData: latestEth1Data) else: template logBlockProcessed(blk) = info "Eth1 block processed", `block` = shortLog(blk), totalDeposits = blk.voteData.deposit_count await dataProvider.fetchBlockDetails(eth1Blocks[0]) if m.eth1Chain.addSuccessorBlock(eth1Blocks[0]): logBlockProcessed eth1Blocks[0] for i in 1 ..< eth1Blocks.len: await dataProvider.fetchBlockDetails(eth1Blocks[i]) if m.eth1Chain.addSuccessorBlock(eth1Blocks[i]): logBlockProcessed eth1Blocks[i] else: raise newException(CorruptDataProvider, "A non-successor Eth1 block reported") else: # A non-continuous chain detected. # This could be the result of a deeper fork that was not reported # properly by the web3 provider. Since this should be an extremely # rare event we can afford to handle it in a relatively inefficient # manner. Let's delete half of our non-finalized chain and try again. let blocksToPop = max(1, m.eth1Chain.totalNonFinalizedBlocks div 2) warn "Web3 provider responded with a non-continous chain of deposits.", backtrackedDeposits = blocksToPop for i in 0 ..< blocksToPop: m.eth1Chain.popBlock() m.depositQueue.addFirstNoWait blk proc isRunning*(m: MainchainMonitor): bool = not m.runFut.isNil func `===`(json: JsonNode, boolean: bool): bool = json.kind == JBool and json.bval == boolean proc run(m: MainchainMonitor, delayBeforeStart: Duration) {.async.} = if delayBeforeStart != ZeroDuration: await sleepAsync(delayBeforeStart) let dataProvider = await m.dataProviderFactory.new(m.depositContractAddress) if dataProvider == nil: error "Failed to initialize Eth1 data provider", provider = m.dataProviderFactory.desc raise newException(CatchableError, "Failed to initialize Eth1 data provider") try: info "Starting Eth1 deposit contract monitoring", contract = $m.depositContractAddress, url = m.dataProviderFactory.desc await dataProvider.onBlockHeaders do (blk: BlockHeader) {.raises: [Defect], gcsafe}: try: m.depositQueue.addLastNoWait(blk) except AsyncQueueFullError: raiseAssert "The depositQueue has no size limit" except Exception: # TODO Investigate why this exception is being raised raiseAssert "queue.addLastNoWait should not raise exceptions" do (err: CatchableError): debug "Error while processing Eth1 block headers subscription", err = err.msg await m.processDeposits(dataProvider) finally: await close(dataProvider) proc safeCancel(fut: var Future[void]) = if not fut.isNil and not fut.finished: fut.cancel() fut = nil proc stop*(m: MainchainMonitor) = safeCancel m.runFut safeCancel m.genesisMonitoringFut proc start(m: MainchainMonitor, delayBeforeStart: Duration) = if m.runFut.isNil: let runFut = m.run(delayBeforeStart) m.runFut = runFut runFut.addCallback do (p: pointer): if runFut.failed: if runFut.error[] of CatchableError: if runFut == m.runFut: error "Mainchain monitor failure, restarting", err = runFut.error.msg m.stop() m.start(5.seconds) else: fatal "Fatal exception reached", err = runFut.error.msg quit 1 proc start*(m: MainchainMonitor) {.inline.} = m.start(0.seconds) proc getLatestEth1BlockHash*(url: string): Future[Eth2Digest] {.async.} = let web3 = await newWeb3(url) try: let blk = await web3.provider.eth_getBlockByNumber("latest", false) return Eth2Digest(data: array[32, byte](blk.hash)) finally: await web3.close() {.pop.}