plugeth/miner/payload_building.go

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// Copyright 2022 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 miner
import (
"crypto/sha256"
"encoding/binary"
"math/big"
"sync"
"time"
"github.com/ethereum/go-ethereum/beacon/engine"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/rlp"
)
// BuildPayloadArgs contains the provided parameters for building payload.
// Check engine-api specification for more details.
// https://github.com/ethereum/execution-apis/blob/main/src/engine/specification.md#payloadattributesv1
type BuildPayloadArgs struct {
Parent common.Hash // The parent block to build payload on top
Timestamp uint64 // The provided timestamp of generated payload
FeeRecipient common.Address // The provided recipient address for collecting transaction fee
Random common.Hash // The provided randomness value
Withdrawals types.Withdrawals // The provided withdrawals
}
// Id computes an 8-byte identifier by hashing the components of the payload arguments.
func (args *BuildPayloadArgs) Id() engine.PayloadID {
// Hash
hasher := sha256.New()
hasher.Write(args.Parent[:])
binary.Write(hasher, binary.BigEndian, args.Timestamp)
hasher.Write(args.Random[:])
hasher.Write(args.FeeRecipient[:])
rlp.Encode(hasher, args.Withdrawals)
var out engine.PayloadID
copy(out[:], hasher.Sum(nil)[:8])
return out
}
// Payload wraps the built payload(block waiting for sealing). According to the
// engine-api specification, EL should build the initial version of the payload
// which has an empty transaction set and then keep update it in order to maximize
// the revenue. Therefore, the empty-block here is always available and full-block
// will be set/updated afterwards.
type Payload struct {
id engine.PayloadID
empty *types.Block
full *types.Block
fullFees *big.Int
stop chan struct{}
lock sync.Mutex
cond *sync.Cond
}
// newPayload initializes the payload object.
func newPayload(empty *types.Block, id engine.PayloadID) *Payload {
payload := &Payload{
id: id,
empty: empty,
stop: make(chan struct{}),
}
log.Info("Starting work on payload", "id", payload.id)
payload.cond = sync.NewCond(&payload.lock)
return payload
}
// update updates the full-block with latest built version.
func (payload *Payload) update(block *types.Block, fees *big.Int, elapsed time.Duration) {
payload.lock.Lock()
defer payload.lock.Unlock()
select {
case <-payload.stop:
return // reject stale update
default:
}
// Ensure the newly provided full block has a higher transaction fee.
// In post-merge stage, there is no uncle reward anymore and transaction
// fee(apart from the mev revenue) is the only indicator for comparison.
if payload.full == nil || fees.Cmp(payload.fullFees) > 0 {
payload.full = block
payload.fullFees = fees
feesInEther := new(big.Float).Quo(new(big.Float).SetInt(fees), big.NewFloat(params.Ether))
log.Info("Updated payload", "id", payload.id, "number", block.NumberU64(), "hash", block.Hash(),
"txs", len(block.Transactions()), "withdrawals", len(block.Withdrawals()), "gas", block.GasUsed(),
"fees", feesInEther, "root", block.Root(), "elapsed", common.PrettyDuration(elapsed))
}
payload.cond.Broadcast() // fire signal for notifying full block
}
// Resolve returns the latest built payload and also terminates the background
// thread for updating payload. It's safe to be called multiple times.
func (payload *Payload) Resolve() *engine.ExecutionPayloadEnvelope {
payload.lock.Lock()
defer payload.lock.Unlock()
select {
case <-payload.stop:
default:
close(payload.stop)
}
if payload.full != nil {
return engine.BlockToExecutableData(payload.full, payload.fullFees)
}
return engine.BlockToExecutableData(payload.empty, big.NewInt(0))
}
// ResolveEmpty is basically identical to Resolve, but it expects empty block only.
// It's only used in tests.
func (payload *Payload) ResolveEmpty() *engine.ExecutionPayloadEnvelope {
payload.lock.Lock()
defer payload.lock.Unlock()
return engine.BlockToExecutableData(payload.empty, big.NewInt(0))
}
// ResolveFull is basically identical to Resolve, but it expects full block only.
// Don't call Resolve until ResolveFull returns, otherwise it might block forever.
func (payload *Payload) ResolveFull() *engine.ExecutionPayloadEnvelope {
payload.lock.Lock()
defer payload.lock.Unlock()
if payload.full == nil {
select {
case <-payload.stop:
return nil
default:
}
// Wait the full payload construction. Note it might block
// forever if Resolve is called in the meantime which
// terminates the background construction process.
payload.cond.Wait()
}
// Terminate the background payload construction
select {
case <-payload.stop:
default:
close(payload.stop)
}
return engine.BlockToExecutableData(payload.full, payload.fullFees)
}
// buildPayload builds the payload according to the provided parameters.
func (w *worker) buildPayload(args *BuildPayloadArgs) (*Payload, error) {
// Build the initial version with no transaction included. It should be fast
// enough to run. The empty payload can at least make sure there is something
// to deliver for not missing slot.
empty, _, err := w.getSealingBlock(args.Parent, args.Timestamp, args.FeeRecipient, args.Random, args.Withdrawals, true)
if err != nil {
return nil, err
}
// Construct a payload object for return.
payload := newPayload(empty, args.Id())
// Spin up a routine for updating the payload in background. This strategy
// can maximum the revenue for including transactions with highest fee.
go func() {
// Setup the timer for re-building the payload. The initial clock is kept
// for triggering process immediately.
timer := time.NewTimer(0)
defer timer.Stop()
// Setup the timer for terminating the process if SECONDS_PER_SLOT (12s in
// the Mainnet configuration) have passed since the point in time identified
// by the timestamp parameter.
endTimer := time.NewTimer(time.Second * 12)
for {
select {
case <-timer.C:
start := time.Now()
block, fees, err := w.getSealingBlock(args.Parent, args.Timestamp, args.FeeRecipient, args.Random, args.Withdrawals, false)
if err == nil {
payload.update(block, fees, time.Since(start))
}
timer.Reset(w.recommit)
case <-payload.stop:
log.Info("Stopping work on payload", "id", payload.id, "reason", "delivery")
return
case <-endTimer.C:
log.Info("Stopping work on payload", "id", payload.id, "reason", "timeout")
return
}
}
}()
return payload, nil
}