plugeth/eth/gasprice/gasprice.go
Felix Lange 9afc6816d2
common/lru: add generic LRU implementation (#26162)
It seems there is no fully typed library implementation of an LRU cache.
So I wrote one. Method names are the same as github.com/hashicorp/golang-lru,
and the new type can be used as a drop-in replacement.

Two reasons to do this:

- It's much easier to understand what a cache is for when the types are right there.
- Performance: the new implementation is slightly faster and performs zero memory
   allocations in Add when the cache is at capacity. Overall, memory usage of the cache
   is much reduced because keys are values are no longer wrapped in interface.
2022-11-14 15:41:56 +01:00

298 lines
9.6 KiB
Go

// Copyright 2015 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"
"math/big"
"sort"
"sync"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/lru"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/rpc"
)
const sampleNumber = 3 // Number of transactions sampled in a block
var (
DefaultMaxPrice = big.NewInt(500 * params.GWei)
DefaultIgnorePrice = big.NewInt(2 * params.Wei)
)
type Config struct {
Blocks int
Percentile int
MaxHeaderHistory int
MaxBlockHistory int
Default *big.Int `toml:",omitempty"`
MaxPrice *big.Int `toml:",omitempty"`
IgnorePrice *big.Int `toml:",omitempty"`
}
// OracleBackend includes all necessary background APIs for oracle.
type OracleBackend interface {
HeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Header, error)
BlockByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Block, error)
GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error)
PendingBlockAndReceipts() (*types.Block, types.Receipts)
ChainConfig() *params.ChainConfig
SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription
}
// Oracle recommends gas prices based on the content of recent
// blocks. Suitable for both light and full clients.
type Oracle struct {
backend OracleBackend
lastHead common.Hash
lastPrice *big.Int
maxPrice *big.Int
ignorePrice *big.Int
cacheLock sync.RWMutex
fetchLock sync.Mutex
checkBlocks, percentile int
maxHeaderHistory, maxBlockHistory int
historyCache *lru.Cache[cacheKey, processedFees]
}
// NewOracle returns a new gasprice oracle which can recommend suitable
// gasprice for newly created transaction.
func NewOracle(backend OracleBackend, params Config) *Oracle {
blocks := params.Blocks
if blocks < 1 {
blocks = 1
log.Warn("Sanitizing invalid gasprice oracle sample blocks", "provided", params.Blocks, "updated", blocks)
}
percent := params.Percentile
if percent < 0 {
percent = 0
log.Warn("Sanitizing invalid gasprice oracle sample percentile", "provided", params.Percentile, "updated", percent)
} else if percent > 100 {
percent = 100
log.Warn("Sanitizing invalid gasprice oracle sample percentile", "provided", params.Percentile, "updated", percent)
}
maxPrice := params.MaxPrice
if maxPrice == nil || maxPrice.Int64() <= 0 {
maxPrice = DefaultMaxPrice
log.Warn("Sanitizing invalid gasprice oracle price cap", "provided", params.MaxPrice, "updated", maxPrice)
}
ignorePrice := params.IgnorePrice
if ignorePrice == nil || ignorePrice.Int64() <= 0 {
ignorePrice = DefaultIgnorePrice
log.Warn("Sanitizing invalid gasprice oracle ignore price", "provided", params.IgnorePrice, "updated", ignorePrice)
} else if ignorePrice.Int64() > 0 {
log.Info("Gasprice oracle is ignoring threshold set", "threshold", ignorePrice)
}
maxHeaderHistory := params.MaxHeaderHistory
if maxHeaderHistory < 1 {
maxHeaderHistory = 1
log.Warn("Sanitizing invalid gasprice oracle max header history", "provided", params.MaxHeaderHistory, "updated", maxHeaderHistory)
}
maxBlockHistory := params.MaxBlockHistory
if maxBlockHistory < 1 {
maxBlockHistory = 1
log.Warn("Sanitizing invalid gasprice oracle max block history", "provided", params.MaxBlockHistory, "updated", maxBlockHistory)
}
cache := lru.NewCache[cacheKey, processedFees](2048)
headEvent := make(chan core.ChainHeadEvent, 1)
backend.SubscribeChainHeadEvent(headEvent)
go func() {
var lastHead common.Hash
for ev := range headEvent {
if ev.Block.ParentHash() != lastHead {
cache.Purge()
}
lastHead = ev.Block.Hash()
}
}()
return &Oracle{
backend: backend,
lastPrice: params.Default,
maxPrice: maxPrice,
ignorePrice: ignorePrice,
checkBlocks: blocks,
percentile: percent,
maxHeaderHistory: maxHeaderHistory,
maxBlockHistory: maxBlockHistory,
historyCache: cache,
}
}
// SuggestTipCap returns a tip cap so that newly created transaction can have a
// very high chance to be included in the following blocks.
//
// Note, for legacy transactions and the legacy eth_gasPrice RPC call, it will be
// necessary to add the basefee to the returned number to fall back to the legacy
// behavior.
func (oracle *Oracle) SuggestTipCap(ctx context.Context) (*big.Int, error) {
head, _ := oracle.backend.HeaderByNumber(ctx, rpc.LatestBlockNumber)
headHash := head.Hash()
// If the latest gasprice is still available, return it.
oracle.cacheLock.RLock()
lastHead, lastPrice := oracle.lastHead, oracle.lastPrice
oracle.cacheLock.RUnlock()
if headHash == lastHead {
return new(big.Int).Set(lastPrice), nil
}
oracle.fetchLock.Lock()
defer oracle.fetchLock.Unlock()
// Try checking the cache again, maybe the last fetch fetched what we need
oracle.cacheLock.RLock()
lastHead, lastPrice = oracle.lastHead, oracle.lastPrice
oracle.cacheLock.RUnlock()
if headHash == lastHead {
return new(big.Int).Set(lastPrice), nil
}
var (
sent, exp int
number = head.Number.Uint64()
result = make(chan results, oracle.checkBlocks)
quit = make(chan struct{})
results []*big.Int
)
for sent < oracle.checkBlocks && number > 0 {
go oracle.getBlockValues(ctx, types.MakeSigner(oracle.backend.ChainConfig(), big.NewInt(int64(number))), number, sampleNumber, oracle.ignorePrice, result, quit)
sent++
exp++
number--
}
for exp > 0 {
res := <-result
if res.err != nil {
close(quit)
return new(big.Int).Set(lastPrice), res.err
}
exp--
// Nothing returned. There are two special cases here:
// - The block is empty
// - All the transactions included are sent by the miner itself.
// In these cases, use the latest calculated price for sampling.
if len(res.values) == 0 {
res.values = []*big.Int{lastPrice}
}
// Besides, in order to collect enough data for sampling, if nothing
// meaningful returned, try to query more blocks. But the maximum
// is 2*checkBlocks.
if len(res.values) == 1 && len(results)+1+exp < oracle.checkBlocks*2 && number > 0 {
go oracle.getBlockValues(ctx, types.MakeSigner(oracle.backend.ChainConfig(), big.NewInt(int64(number))), number, sampleNumber, oracle.ignorePrice, result, quit)
sent++
exp++
number--
}
results = append(results, res.values...)
}
price := lastPrice
if len(results) > 0 {
sort.Sort(bigIntArray(results))
price = results[(len(results)-1)*oracle.percentile/100]
}
if price.Cmp(oracle.maxPrice) > 0 {
price = new(big.Int).Set(oracle.maxPrice)
}
oracle.cacheLock.Lock()
oracle.lastHead = headHash
oracle.lastPrice = price
oracle.cacheLock.Unlock()
return new(big.Int).Set(price), nil
}
type results struct {
values []*big.Int
err error
}
type txSorter struct {
txs []*types.Transaction
baseFee *big.Int
}
func newSorter(txs []*types.Transaction, baseFee *big.Int) *txSorter {
return &txSorter{
txs: txs,
baseFee: baseFee,
}
}
func (s *txSorter) Len() int { return len(s.txs) }
func (s *txSorter) Swap(i, j int) {
s.txs[i], s.txs[j] = s.txs[j], s.txs[i]
}
func (s *txSorter) Less(i, j int) bool {
// It's okay to discard the error because a tx would never be
// accepted into a block with an invalid effective tip.
tip1, _ := s.txs[i].EffectiveGasTip(s.baseFee)
tip2, _ := s.txs[j].EffectiveGasTip(s.baseFee)
return tip1.Cmp(tip2) < 0
}
// getBlockPrices calculates the lowest transaction gas price in a given block
// and sends it to the result channel. If the block is empty or all transactions
// are sent by the miner itself(it doesn't make any sense to include this kind of
// transaction prices for sampling), nil gasprice is returned.
func (oracle *Oracle) getBlockValues(ctx context.Context, signer types.Signer, blockNum uint64, limit int, ignoreUnder *big.Int, result chan results, quit chan struct{}) {
block, err := oracle.backend.BlockByNumber(ctx, rpc.BlockNumber(blockNum))
if block == nil {
select {
case result <- results{nil, err}:
case <-quit:
}
return
}
// Sort the transaction by effective tip in ascending sort.
txs := make([]*types.Transaction, len(block.Transactions()))
copy(txs, block.Transactions())
sorter := newSorter(txs, block.BaseFee())
sort.Sort(sorter)
var prices []*big.Int
for _, tx := range sorter.txs {
tip, _ := tx.EffectiveGasTip(block.BaseFee())
if ignoreUnder != nil && tip.Cmp(ignoreUnder) == -1 {
continue
}
sender, err := types.Sender(signer, tx)
if err == nil && sender != block.Coinbase() {
prices = append(prices, tip)
if len(prices) >= limit {
break
}
}
}
select {
case result <- results{prices, nil}:
case <-quit:
}
}
type bigIntArray []*big.Int
func (s bigIntArray) Len() int { return len(s) }
func (s bigIntArray) Less(i, j int) bool { return s[i].Cmp(s[j]) < 0 }
func (s bigIntArray) Swap(i, j int) { s[i], s[j] = s[j], s[i] }