plugeth/eth/gasprice/feehistory.go

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// Copyright 2021 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package gasprice
import (
"context"
"errors"
"math/big"
"sort"
"sync/atomic"
"github.com/ethereum/go-ethereum/consensus/misc"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/rpc"
)
var (
errInvalidPercentiles = errors.New("Invalid reward percentiles")
errRequestBeyondHead = errors.New("Request beyond head block")
)
const maxBlockCount = 1024 // number of blocks retrievable with a single query
// blockFees represents a single block for processing
type blockFees struct {
// set by the caller
blockNumber rpc.BlockNumber
header *types.Header
block *types.Block // only set if reward percentiles are requested
receipts types.Receipts
// filled by processBlock
reward []*big.Int
baseFee, nextBaseFee *big.Int
gasUsedRatio float64
err error
}
// txGasAndReward is sorted in ascending order based on reward
type (
txGasAndReward struct {
gasUsed uint64
reward *big.Int
}
sortGasAndReward []txGasAndReward
)
func (s sortGasAndReward) Len() int { return len(s) }
func (s sortGasAndReward) Swap(i, j int) {
s[i], s[j] = s[j], s[i]
}
func (s sortGasAndReward) Less(i, j int) bool {
return s[i].reward.Cmp(s[j].reward) < 0
}
// processBlock takes a blockFees structure with the blockNumber, the header and optionally
// the block field filled in, retrieves the block from the backend if not present yet and
// fills in the rest of the fields.
func (oracle *Oracle) processBlock(bf *blockFees, percentiles []float64) {
chainconfig := oracle.backend.ChainConfig()
if bf.baseFee = bf.header.BaseFee; bf.baseFee == nil {
bf.baseFee = new(big.Int)
}
if chainconfig.IsLondon(big.NewInt(int64(bf.blockNumber + 1))) {
bf.nextBaseFee = misc.CalcBaseFee(chainconfig, bf.header)
} else {
bf.nextBaseFee = new(big.Int)
}
bf.gasUsedRatio = float64(bf.header.GasUsed) / float64(bf.header.GasLimit)
if len(percentiles) == 0 {
// rewards were not requested, return null
return
}
if bf.block == nil || (bf.receipts == nil && len(bf.block.Transactions()) != 0) {
log.Error("Block or receipts are missing while reward percentiles are requested")
return
}
bf.reward = make([]*big.Int, len(percentiles))
if len(bf.block.Transactions()) == 0 {
// return an all zero row if there are no transactions to gather data from
for i := range bf.reward {
bf.reward[i] = new(big.Int)
}
return
}
sorter := make(sortGasAndReward, len(bf.block.Transactions()))
for i, tx := range bf.block.Transactions() {
reward, _ := tx.EffectiveGasTip(bf.block.BaseFee())
sorter[i] = txGasAndReward{gasUsed: bf.receipts[i].GasUsed, reward: reward}
}
sort.Sort(sorter)
var txIndex int
sumGasUsed := sorter[0].gasUsed
for i, p := range percentiles {
thresholdGasUsed := uint64(float64(bf.block.GasUsed()) * p / 100)
for sumGasUsed < thresholdGasUsed && txIndex < len(bf.block.Transactions())-1 {
txIndex++
sumGasUsed += sorter[txIndex].gasUsed
}
bf.reward[i] = sorter[txIndex].reward
}
}
// resolveBlockRange resolves the specified block range to absolute block numbers while also
// enforcing backend specific limitations. The pending block and corresponding receipts are
// also returned if requested and available.
// Note: an error is only returned if retrieving the head header has failed. If there are no
// retrievable blocks in the specified range then zero block count is returned with no error.
func (oracle *Oracle) resolveBlockRange(ctx context.Context, lastBlockNumber rpc.BlockNumber, blockCount, maxHistory int) (*types.Block, types.Receipts, rpc.BlockNumber, int, error) {
var (
headBlockNumber rpc.BlockNumber
pendingBlock *types.Block
pendingReceipts types.Receipts
)
// query either pending block or head header and set headBlockNumber
if lastBlockNumber == rpc.PendingBlockNumber {
if pendingBlock, pendingReceipts = oracle.backend.PendingBlockAndReceipts(); pendingBlock != nil {
lastBlockNumber = rpc.BlockNumber(pendingBlock.NumberU64())
headBlockNumber = lastBlockNumber - 1
} else {
// pending block not supported by backend, process until latest block
lastBlockNumber = rpc.LatestBlockNumber
blockCount--
if blockCount == 0 {
return nil, nil, 0, 0, nil
}
}
}
if pendingBlock == nil {
// if pending block is not fetched then we retrieve the head header to get the head block number
if latestHeader, err := oracle.backend.HeaderByNumber(ctx, rpc.LatestBlockNumber); err == nil {
headBlockNumber = rpc.BlockNumber(latestHeader.Number.Uint64())
} else {
return nil, nil, 0, 0, err
}
}
if lastBlockNumber == rpc.LatestBlockNumber {
lastBlockNumber = headBlockNumber
} else if pendingBlock == nil && lastBlockNumber > headBlockNumber {
return nil, nil, 0, 0, errRequestBeyondHead
}
if maxHistory != 0 {
// limit retrieval to the given number of latest blocks
if tooOldCount := int64(headBlockNumber) - int64(maxHistory) - int64(lastBlockNumber) + int64(blockCount); tooOldCount > 0 {
// tooOldCount is the number of requested blocks that are too old to be served
if int64(blockCount) > tooOldCount {
blockCount -= int(tooOldCount)
} else {
return nil, nil, 0, 0, nil
}
}
}
// ensure not trying to retrieve before genesis
if rpc.BlockNumber(blockCount) > lastBlockNumber+1 {
blockCount = int(lastBlockNumber + 1)
}
return pendingBlock, pendingReceipts, lastBlockNumber, blockCount, nil
}
// FeeHistory returns data relevant for fee estimation based on the specified range of blocks.
// The range can be specified either with absolute block numbers or ending with the latest
// or pending block. Backends may or may not support gathering data from the pending block
// or blocks older than a certain age (specified in maxHistory). The first block of the
// actually processed range is returned to avoid ambiguity when parts of the requested range
// are not available or when the head has changed during processing this request.
// Three arrays are returned based on the processed blocks:
// - reward: the requested percentiles of effective priority fees per gas of transactions in each
// block, sorted in ascending order and weighted by gas used.
// - baseFee: base fee per gas in the given block
// - gasUsedRatio: gasUsed/gasLimit in the given block
// Note: baseFee includes the next block after the newest of the returned range, because this
// value can be derived from the newest block.
func (oracle *Oracle) FeeHistory(ctx context.Context, blockCount int, lastBlockNumber rpc.BlockNumber, rewardPercentiles []float64) (firstBlockNumber rpc.BlockNumber, reward [][]*big.Int, baseFee []*big.Int, gasUsedRatio []float64, err error) {
if blockCount < 1 {
// returning with no data and no error means there are no retrievable blocks
return
}
if blockCount > maxBlockCount {
blockCount = maxBlockCount
}
for i, p := range rewardPercentiles {
if p < 0 || p > 100 || (i > 0 && p < rewardPercentiles[i-1]) {
return 0, nil, nil, nil, errInvalidPercentiles
}
}
processBlocks := len(rewardPercentiles) != 0
// limit retrieval to maxHistory if set
var maxHistory int
if processBlocks {
maxHistory = oracle.maxBlockHistory
} else {
maxHistory = oracle.maxHeaderHistory
}
var (
pendingBlock *types.Block
pendingReceipts types.Receipts
)
if pendingBlock, pendingReceipts, lastBlockNumber, blockCount, err = oracle.resolveBlockRange(ctx, lastBlockNumber, blockCount, maxHistory); err != nil || blockCount == 0 {
return
}
firstBlockNumber = lastBlockNumber + 1 - rpc.BlockNumber(blockCount)
processNext := int64(firstBlockNumber)
resultCh := make(chan *blockFees, blockCount)
threadCount := 4
if blockCount < threadCount {
threadCount = blockCount
}
for i := 0; i < threadCount; i++ {
go func() {
for {
blockNumber := rpc.BlockNumber(atomic.AddInt64(&processNext, 1) - 1)
if blockNumber > lastBlockNumber {
return
}
bf := &blockFees{blockNumber: blockNumber}
if pendingBlock != nil && blockNumber >= rpc.BlockNumber(pendingBlock.NumberU64()) {
bf.block, bf.receipts = pendingBlock, pendingReceipts
} else {
if processBlocks {
bf.block, bf.err = oracle.backend.BlockByNumber(ctx, blockNumber)
if bf.block != nil {
bf.receipts, bf.err = oracle.backend.GetReceipts(ctx, bf.block.Hash())
}
} else {
bf.header, bf.err = oracle.backend.HeaderByNumber(ctx, blockNumber)
}
}
if bf.block != nil {
bf.header = bf.block.Header()
}
if bf.header != nil {
oracle.processBlock(bf, rewardPercentiles)
}
// send to resultCh even if empty to guarantee that blockCount items are sent in total
resultCh <- bf
}
}()
}
reward = make([][]*big.Int, blockCount)
baseFee = make([]*big.Int, blockCount+1)
gasUsedRatio = make([]float64, blockCount)
firstMissing := blockCount
for ; blockCount > 0; blockCount-- {
bf := <-resultCh
if bf.err != nil {
return 0, nil, nil, nil, bf.err
}
i := int(bf.blockNumber - firstBlockNumber)
if bf.header != nil {
reward[i], baseFee[i], baseFee[i+1], gasUsedRatio[i] = bf.reward, bf.baseFee, bf.nextBaseFee, bf.gasUsedRatio
} else {
// getting no block and no error means we are requesting into the future (might happen because of a reorg)
if i < firstMissing {
firstMissing = i
}
}
}
if firstMissing == 0 {
return 0, nil, nil, nil, nil
}
if processBlocks {
reward = reward[:firstMissing]
} else {
reward = nil
}
baseFee, gasUsedRatio = baseFee[:firstMissing+1], gasUsedRatio[:firstMissing]
return
}