go-ethereum/beacon/light/api/api_server.go
Felföldi Zsolt 256d4b099c
beacon/light: request finality update explicitly when necessary (#29567)
This PR adds an extra mechanism to sync.HeadSync that tries to retrieve the latest finality update from every server each time it sends an optimistic update in a new epoch (unless we already have a validated finality update attested in the same epoch). 

Note that this is not necessary and does not happen if the new finality update is delivered before the optimistic update. The spec only mandates light_client_finality_update events when a new epoch is finalized. If the chain does not finalize for a while then we might need an explicit request that returns a finality proof that proves the same finality epoch from the latest attested epoch.
2024-04-23 13:31:32 +02:00

115 lines
4.4 KiB
Go
Executable File

// Copyright 2023 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 api
import (
"reflect"
"github.com/ethereum/go-ethereum/beacon/light/request"
"github.com/ethereum/go-ethereum/beacon/light/sync"
"github.com/ethereum/go-ethereum/beacon/types"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/log"
)
// ApiServer is a wrapper around BeaconLightApi that implements request.requestServer.
type ApiServer struct {
api *BeaconLightApi
eventCallback func(event request.Event)
unsubscribe func()
}
// NewApiServer creates a new ApiServer.
func NewApiServer(api *BeaconLightApi) *ApiServer {
return &ApiServer{api: api}
}
// Subscribe implements request.requestServer.
func (s *ApiServer) Subscribe(eventCallback func(event request.Event)) {
s.eventCallback = eventCallback
listener := HeadEventListener{
OnNewHead: func(slot uint64, blockRoot common.Hash) {
log.Debug("New head received", "slot", slot, "blockRoot", blockRoot)
eventCallback(request.Event{Type: sync.EvNewHead, Data: types.HeadInfo{Slot: slot, BlockRoot: blockRoot}})
},
OnOptimistic: func(update types.OptimisticUpdate) {
log.Debug("New optimistic update received", "slot", update.Attested.Slot, "blockRoot", update.Attested.Hash(), "signerCount", update.Signature.SignerCount())
eventCallback(request.Event{Type: sync.EvNewOptimisticUpdate, Data: update})
},
OnFinality: func(update types.FinalityUpdate) {
log.Debug("New finality update received", "slot", update.Attested.Slot, "blockRoot", update.Attested.Hash(), "signerCount", update.Signature.SignerCount())
eventCallback(request.Event{Type: sync.EvNewFinalityUpdate, Data: update})
},
OnError: func(err error) {
log.Warn("Head event stream error", "err", err)
},
}
s.unsubscribe = s.api.StartHeadListener(listener)
}
// SendRequest implements request.requestServer.
func (s *ApiServer) SendRequest(id request.ID, req request.Request) {
go func() {
var resp request.Response
var err error
switch data := req.(type) {
case sync.ReqUpdates:
log.Debug("Beacon API: requesting light client update", "reqid", id, "period", data.FirstPeriod, "count", data.Count)
var r sync.RespUpdates
r.Updates, r.Committees, err = s.api.GetBestUpdatesAndCommittees(data.FirstPeriod, data.Count)
resp = r
case sync.ReqHeader:
var r sync.RespHeader
log.Debug("Beacon API: requesting header", "reqid", id, "hash", common.Hash(data))
r.Header, r.Canonical, r.Finalized, err = s.api.GetHeader(common.Hash(data))
resp = r
case sync.ReqCheckpointData:
log.Debug("Beacon API: requesting checkpoint data", "reqid", id, "hash", common.Hash(data))
resp, err = s.api.GetCheckpointData(common.Hash(data))
case sync.ReqBeaconBlock:
log.Debug("Beacon API: requesting block", "reqid", id, "hash", common.Hash(data))
resp, err = s.api.GetBeaconBlock(common.Hash(data))
case sync.ReqFinality:
log.Debug("Beacon API: requesting finality update")
resp, err = s.api.GetFinalityUpdate()
default:
}
if err != nil {
log.Warn("Beacon API request failed", "type", reflect.TypeOf(req), "reqid", id, "err", err)
s.eventCallback(request.Event{Type: request.EvFail, Data: request.RequestResponse{ID: id, Request: req}})
} else {
log.Debug("Beacon API request answered", "type", reflect.TypeOf(req), "reqid", id)
s.eventCallback(request.Event{Type: request.EvResponse, Data: request.RequestResponse{ID: id, Request: req, Response: resp}})
}
}()
}
// Unsubscribe implements request.requestServer.
// Note: Unsubscribe should not be called concurrently with Subscribe.
func (s *ApiServer) Unsubscribe() {
if s.unsubscribe != nil {
s.unsubscribe()
s.unsubscribe = nil
}
}
// Name implements request.Server
func (s *ApiServer) Name() string {
return s.api.url
}