lbryio/chainquery

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daemon/processing/block.go

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2 hrs
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package processing

import (
    "fmt"
    "sort"
    "strconv"
    "strings"
    "sync"
    "time"

    "github.com/lbryio/chainquery/lbrycrd"
    "github.com/lbryio/chainquery/metrics"
    "github.com/lbryio/chainquery/model"
    "github.com/lbryio/chainquery/sockety"
    "github.com/lbryio/chainquery/twilio"
    "github.com/lbryio/chainquery/util"

    "github.com/lbryio/lbry.go/v2/extras/errors"
    "github.com/lbryio/lbry.go/v2/extras/stop"

    "github.com/OdyseeTeam/sockety/socketyapi"
    "github.com/sirupsen/logrus"
    "github.com/volatiletech/null/v8"
    "github.com/volatiletech/sqlboiler/v4/boil"
    "github.com/volatiletech/sqlboiler/v4/queries/qm"
)

// BlockLock is used to lock block processing to a single parent thread.
var BlockLock = sync.Mutex{}

// ManualShutDownError Error with special handling. Used to stop the concurrency pipeline for processing blocks midway.
var ManualShutDownError = errors.Err("Daemon stopped manually!")

// RunBlockProcessing runs the processing of a block at a specific height. While any height can be passed in it is
// important to note that if the previous block is not processed it will panic to prevent corruption because blocks
// must be processed in order.
func RunBlockProcessing(stopper *stop.Group, height uint64) uint64 {
    defer metrics.Processing(time.Now(), "block")
    defer util.TimeTrack(time.Now(), "runBlockProcessing", "daemonprofile")
    if height == 0 {
        err := processGenesisBlock()
        if err != nil {
            logrus.Fatal("Error processing Genesis block!", err)
        }
        return height
    }
    jsonBlock, err := getBlockToProcess(&height)
    if err != nil {
        logrus.Error("Get Block Error: ", err)
        //ToDo - Should just return error...that is for another day
        return height - 1
    }
    reorgHeight, err := checkHandleReorg(height, jsonBlock.PreviousBlockHash)
    if err != nil {
        logrus.Error("Reorg Handling Error: ", err)
        //ToDo - Should just return error...that is for another day
        return height - 1
    }
    if reorgHeight != height {
        return reorgHeight
    }

    //This is an important lock to make sure we don't concurrently save transaction inputs/outputs accidentally via the
    // mempool sync.
    BlockLock.Lock()
    defer BlockLock.Unlock()

    block, err := ProcessBlock(height, stopper, jsonBlock)
    if err != nil {
        metrics.ProcessingFailures.WithLabelValues("block").Inc()
        rollBackHeight := height - 1
        blockRemovalError := block.DeleteG()
        if blockRemovalError != nil {
            logrus.Panicf("Could not delete block with bad data. Data corruption imminent at height %d. The block must be remove manually to continue.", height)
        }
        if err.Error() == ManualShutDownError.Error() {
            return rollBackHeight
        }
        logrus.Error("Block Processing Error: ", errors.FullTrace(err))
        logrus.Warning("Ran into transaction sync error at height", height, ". Rolling block back to height", height-1)
        //ToDo - Should just return error...that is for another day
        return rollBackHeight
    }

    return height
}

// ProcessBlock processing a specific block and returns an error. Use this to process a block having a custom handling
// of the error.
func ProcessBlock(height uint64, stopper *stop.Group, jsonBlock *lbrycrd.GetBlockResponse) (*model.Block, error) {
    block := parseBlockInfo(height, jsonBlock)
    err := setPreviousBlockInfo(height, jsonBlock.Hash)
    if err != nil {
        logrus.Errorf("failed to set previous block next hash: %s", err.Error())
    }
    txs := jsonBlock.Tx
    go sockety.SendNotification(socketyapi.SendNotificationArgs{
        Service: socketyapi.BlockChain,
        Type:    "new_block",
        IDs:     []string{"blocks", strconv.Itoa(int(height))},
        Data:    map[string]interface{}{"block": jsonBlock},
    })
    return block, syncTransactionsOfBlock(stopper, txs, block.BlockTime, block.Height)
}

// setPreviousBlockInfo sets the NextBlockHash field from the previous block
func setPreviousBlockInfo(currentHeight uint64, currentBLockHash string) error {
    if currentHeight < 1 {
        return nil
    }
    prevBlock, err := model.Blocks(qm.Where(model.BlockColumns.Height+"=?", currentHeight-1)).OneG()
    if err != nil {
        return errors.Err(err)
    }
    prevBlock.NextBlockHash.SetValid(currentBLockHash)
    err = prevBlock.UpdateG(boil.Infer())
    return errors.Err(err)
}

func parseBlockInfo(blockHeight uint64, jsonBlock *lbrycrd.GetBlockResponse) (block *model.Block) {
    block = &model.Block{}
    foundBlock, _ := model.Blocks(qm.Where(model.BlockColumns.Hash+"=?", jsonBlock.Hash)).OneG()
    if foundBlock != nil {
        block = foundBlock
    }

    block.Bits = jsonBlock.Bits
    block.Chainwork = jsonBlock.ChainWork
    block.Confirmations = uint(jsonBlock.Confirmations)
    block.Difficulty = jsonBlock.Difficulty
    block.Hash = jsonBlock.Hash
    block.Height = blockHeight
    block.MerkleRoot = jsonBlock.MerkleRoot
    block.NameClaimRoot = jsonBlock.NameClaimRoot
    block.Nonce = jsonBlock.Nonce
    block.PreviousBlockHash.SetValid(jsonBlock.PreviousBlockHash)
    block.NextBlockHash = null.NewString(jsonBlock.NextBlockHash, jsonBlock.NextBlockHash != "")
    block.BlockSize = uint64(jsonBlock.Size)
    block.BlockTime = uint64(jsonBlock.Time)
    block.Version = uint64(jsonBlock.Version)
    block.VersionHex = jsonBlock.VersionHex
    block.TXCount = int(jsonBlock.NTx)
    //block.TransactionHashes.SetValid(strings.Join(jsonBlock.Tx, ",")) //we don't need this, it's extremely redundant and heavy

    var err error
    if foundBlock != nil {
        err = block.UpdateG(boil.Infer())
    } else {
        err = block.InsertG(boil.Infer())
    }
    if err != nil {
        logrus.Panic(err)
    }

    return block
}

func processGenesisBlock() error {
    genesisVerbose, genesis, err := lbrycrd.GetGenesisBlock()
    if err != nil {
        return errors.Err(err)
    }
    //This is an important lock to make sure we don't concurrently save transaction inputs/outputs accidentally via the
    // mempool sync.
    BlockLock.Lock()
    defer BlockLock.Unlock()
    block := parseBlockInfo(0, genesis)
    for _, tx := range genesisVerbose.Tx {
        tx.BlockHash = genesis.Hash
        err := ProcessTx(&tx, block.BlockTime, 0)
        if err != nil {
            return errors.Err(err)
        }
    }
    return nil
}

type txSyncManager struct {
    daemonStopper *stop.Group
    queueStopper  *stop.Group
    syncStopper   *stop.Group
    workerStopper *stop.Group
    resultsCh     chan txProcessResult
    redoJobsCh    chan txToProcess
    jobsCh        chan txToProcess
    errorsCh      chan error
}

func syncTransactionsOfBlock(stopper *stop.Group, txs []string, blockTime uint64, blockHeight uint64) error {
    q("SYNC: started - " + strconv.Itoa(int(blockHeight)))
    // Initialization
    const maxErrorsPerBlockSync = 2
    // Error handling logic can be tested by decreasing the number of times a transaction can fail to 0.
    manager := txSyncManager{
        daemonStopper: stop.New(stopper),
        queueStopper:  stop.New(nil),
        syncStopper:   stop.New(nil),
        workerStopper: stop.New(nil),
        errorsCh:      make(chan error, maxErrorsPerBlockSync),
        resultsCh:     make(chan txProcessResult),
        redoJobsCh:    make(chan txToProcess, len(txs)),
        jobsCh:        make(chan txToProcess),
    }
    workers := util.Min(len(txs), MaxParallelTxProcessing)
    initTxWorkers(manager.workerStopper, workers, manager.jobsCh, manager.resultsCh)
    // Queue up n threads of transactions
    manager.queueStopper.Add(1)
    go queueTx(txs, blockTime, blockHeight, &manager)
    q("SYNC: launched queueing")
    //Setup reprocessing queue
    manager.syncStopper.Add(1)
    go reprocessQueue(&manager)
    // Handle the results
    manager.syncStopper.Add(1)
    go handleTxResults(len(txs), &manager)
    q("SYNC: launched handling")
    // Check for queueing errors ( ie. lbrycrd fetch)
    err := <-manager.errorsCh
    if err != nil {
        return errors.Err(err)
    }
    q("SYNC: received 1st on errorCh")

    // Wait for first handling error/nil first error is sent when tx fails x times or daemon is shutdown
    err = <-manager.errorsCh
    q("SYNC: received 2nd on errorCh")
    q("SYNC: stop workers...")
    manager.workerStopper.Stop()
    q("SYNC: stop sync...")
    manager.syncStopper.Stop()
    q("SYNC: wait for workers... - " + strconv.Itoa(int(blockHeight)))
    manager.workerStopper.StopAndWait()
    q("SYNC: wait for sync - " + strconv.Itoa(int(blockHeight)))
    manager.syncStopper.StopAndWait()
    q("SYNC: stopped - " + strconv.Itoa(int(blockHeight)))
    q("SYNC: closing redo channel")
    close(manager.redoJobsCh)
    q("SYNC: closing result channel")
    close(manager.resultsCh)
    q("SYNC: closing error channel")
    close(manager.errorsCh)
    q("SYNC: closing jobs channel")
    close(manager.jobsCh)
    q("SYNC: finished - " + strconv.Itoa(int(blockHeight)))
    return err
}

// q enables extensive logging on the concurrency of Chainquery. If there is every a deadlock and it's reproducible
// you can use this to debug it. Don't get stuck on the 'q' name either. It was literally a rare single letter that
// I chose, thats' it.
func q(a string) {
    if false {
        println(a)
    }
}

// MaxFailures tells Chainquery how many failures a transaction can have before we rollback the block and try to process it
// it again. This is to stop an indefinite loop. Since transactions can be dependant on one another they can fail if not
// processed in the right order. We allow parallel processing by putting transactions into a queue, and if they fail to
// process, for example if its dependant transaction has not been processed yet, then we allow to go back into the queue
// x times ( MaxFailures ).
var MaxFailures int

func handleTxResults(nrToHandle int, manager *txSyncManager) {
    defer manager.syncStopper.Done()
    q("HANDLE: start handling")
    leftToProcess := nrToHandle
    for {
        q("HANDLE: waiting for next result...")
        select {
        case <-manager.daemonStopper.Ch():
            logrus.Info("stopping tx sync...")
            handleFailure(errors.Err("Daemon stopped manually!"), manager)
            return
        case <-manager.syncStopper.Ch():
            q("HANDLE: stopping handling...")
            return
        case txResult := <-manager.resultsCh:
            q("HANDLE: start handling new result.." + txResult.tx.Txid)
            leftToProcess--
            if txResult.failcount > MaxFailures {
                err := errors.Prefix("transaction "+txResult.tx.Txid+" failed more than "+strconv.Itoa(MaxFailures)+" times", txResult.err)
                handleFailure(err, manager)
                continue
            }
            if txResult.err != nil { // Try again if fails this time.
                leftToProcess++
                q("HANDLE: start sending to worker..." + txResult.tx.Txid)
                manager.redoJobsCh <- txToProcess{tx: txResult.tx, blockTime: txResult.blockTime, failcount: txResult.failcount, blockHeight: txResult.blockHeight}
                q("HANDLE: end sending to worker..." + txResult.tx.Txid)
                q("HANDLE: finish handling new result.." + txResult.tx.Txid)
                //continue
            }
            if leftToProcess == 0 {
                q("HANDLE: start passing done..")
                manager.errorsCh <- nil
                q("HANDLE: end passing done..")
                q("HANDLE: end handling..")
                return
            }
            q("HANDLE: go to next loop..")
            continue
        }
    }
}

func queueTx(txs []string, blockTime uint64, blockHeight uint64, manager *txSyncManager) {
    defer manager.queueStopper.Done()
    q("QUEUE: start of queuing")
    txRawMap := make(map[string]*lbrycrd.TxRawResult)
    depthMap := make(map[string]int, len(txs))
    txSlice := make([]*lbrycrd.TxRawResult, len(txs))
    for i := range txs {
        select {
        case <-manager.queueStopper.Ch():
            q("QUEUE: stopping lbrycrd getting...")
            manager.errorsCh <- nil
            return
        default:
            q("QUEUE:  start getting lbrycrd transaction..." + txs[i])
            jsonTx, err := lbrycrd.GetRawTransactionResponse(txs[i])
            if err != nil {
                manager.errorsCh <- errors.Prefix("GetRawTxError"+txs[i], err)
                return
            }
            txRawMap[jsonTx.Txid] = jsonTx
            txSlice[i] = jsonTx
            depthMap[jsonTx.Txid] = 1
            q("QUEUE:  end getting lbrycrd transaction..." + txs[i])
        }
    }
    txSet, ok := optimizeOrderToProcess(txRawMap, depthMap)
    q("QUEUE: start interaction of " + strconv.Itoa(len(txSet)) + " transactions")
    if !ok {
        txSet = txSlice
    }
    for _, jsonTx := range txSet {
        select {
        case <-manager.queueStopper.Ch():
            q("QUEUE:  stopping processing " + jsonTx.Txid)
            manager.errorsCh <- nil
            return
        default:
            q("QUEUE: start processing..." + jsonTx.Txid)
            manager.jobsCh <- txToProcess{tx: jsonTx, blockTime: blockTime, blockHeight: blockHeight}
            q("QUEUE: end processing..." + jsonTx.Txid)
        }
    }
    q("QUEUE: end of queuing")
    manager.errorsCh <- nil
    q("QUEUE: end of queuing...passed nil to errorCh")
}

// flush is a helper function for handling the results.
func flush(channel <-chan txProcessResult) {
    for range channel {
    }
}

func handleFailure(err error, manager *txSyncManager) {
    q("HANDLE: start passing error...")
    manager.queueStopper.Stop()
    q("HANDLE: flushing channel...")
    //Clears queue if any additional finished jobs come in at this point.
    // It also stops blocking during stopping.
    go flush(manager.resultsCh)
    q("HANDLE: stopping queue...")
    manager.queueStopper.StopAndWait()
    q("HANDLE: stopped queue...")
    q("HANDLE: stopping workers...")
    manager.workerStopper.Stop()
    q("HANDLE: stopped workers...")
    manager.errorsCh <- err
    q("HANDLE: finish passing error...")
}

func getBlockToProcess(height *uint64) (*lbrycrd.GetBlockResponse, error) {
    hash, err := lbrycrd.GetBlockHash(*height)
    if err != nil {
        return nil, errors.Prefix(fmt.Sprintf("GetBlockHash Error(%d)", *height), err)
    }
    jsonBlock, err := lbrycrd.GetBlock(*hash)
    if err != nil {
        return nil, errors.Prefix("GetBlock Error("+*hash+")", err)
    }

    return jsonBlock, nil
}

func checkHandleReorg(height uint64, chainPrevHash string) (uint64, error) {
    prevHeight := height - 1
    depth := 0
    if height > 0 {
        prevBlock, err := model.Blocks(qm.Where(model.BlockColumns.Height+"=?", prevHeight), qm.Load("BlockHashTransactions")).OneG()
        if err != nil {
            return height, errors.Prefix("error getting block@"+strconv.Itoa(int(prevHeight)), err)
        }
        //Recursively delete blocks until they match or a reorg of depth 100 == failure of logic.
        for prevBlock.Hash != chainPrevHash && depth < 100 && prevHeight > 0 {
            hashes := make([]string, len(prevBlock.R.BlockHashTransactions))
            for i, th := range prevBlock.R.BlockHashTransactions {
                hashes[i] = th.Hash
            }
            fmt.Printf("block %s at height %d to be removed due to reorg. TX-> %s", prevBlock.Hash, prevBlock.Height, strings.Join(hashes, ","))
            logrus.Printf("block %s at height %d to be removed due to reorg. TX-> %s", prevBlock.Hash, prevBlock.Height, strings.Join(hashes, ","))
            // Delete because it needs to be reprocessed due to reorg
            err = prevBlock.DeleteG()
            if err != nil {
                return height, errors.Prefix("error deleting block@"+strconv.Itoa(int(prevHeight)), err)
            }

            depth++

            // Set chainPrevHash to new previous blocks prevhash to check next depth
            jsonBlock, err := getBlockToProcess(&prevHeight)
            if err != nil {
                return height, errors.Prefix("error getting block@"+strconv.Itoa(int(prevHeight))+" from lbrycrd", err)
            }
            chainPrevHash = jsonBlock.PreviousBlockHash

            // Decrement height and set prevBlock to the new previous
            prevHeight--
            prevBlock, err = model.Blocks(qm.Where(model.BlockColumns.Height+"=?", prevHeight)).OneG()
            if err != nil {
                return height, errors.Prefix("error getting previous block@"+strconv.Itoa(int(prevHeight)), err)
            }
        }
        if depth > 0 {
            message := fmt.Sprintf("Reorg detected of depth %d at height %d,(last matching height %d) handling reorg processing!", depth, height, prevHeight)
            logrus.Warning(message)
            if depth > 2 {
                twilio.SendSMS(message)
            }
            return prevHeight, nil
        }
    }
    return height, nil
}

func reprocessQueue(manager *txSyncManager) {
    defer manager.syncStopper.Done()
    for {
        select {
        case <-manager.syncStopper.Ch():
            q("REDO: stopping redo jobs")
            return
        case redoJob := <-manager.redoJobsCh:
            q("REDO: start send new redo job - " + redoJob.tx.Txid)
            manager.jobsCh <- redoJob
            q("REDO: end send new redo job - " + redoJob.tx.Txid)
        }
    }
}
func checkDepth(tx *lbrycrd.TxRawResult, txMap map[string]*lbrycrd.TxRawResult, depthMap map[string]int, start time.Time) bool {
    if time.Since(start) > 5*time.Second {
        return false
    }
    for _, vin := range tx.Vin {
        if txchild, ok := txMap[vin.TxID]; ok {
            depthMap[vin.TxID]++
            return checkDepth(txchild, txMap, depthMap, start)
        }
    }
    return true
}

func optimizeOrderToProcess(txMap map[string]*lbrycrd.TxRawResult, depthMap map[string]int) ([]*lbrycrd.TxRawResult, bool) {
    start := time.Now()
    successful := false
    for _, tx := range txMap {
        successful = checkDepth(tx, txMap, depthMap, start)
    }

    type depthPair struct {
        TxID  string
        Count int
    }

    var list []depthPair
    for k, v := range depthMap {
        list = append(list, depthPair{k, v})
    }

    sort.Slice(list, func(i, j int) bool {
        return list[i].Count > list[j].Count
    })

    orderedTx := make([]*lbrycrd.TxRawResult, len(list))
    for i := range list {
        orderedTx[i] = txMap[list[i].TxID]
        //Additional debugging to output the order in which transactions are processed.
        q("Tx " + list[i].TxID + " Count " + strconv.Itoa(list[i].Count))
    }
    return orderedTx, successful
}