vouch/strategies/attestationdata/first/attestationdata.go

65 lines
2.4 KiB
Go

// Copyright © 2020 Attestant Limited.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package first
import (
"context"
"time"
eth2client "github.com/attestantio/go-eth2-client"
"github.com/attestantio/go-eth2-client/spec/phase0"
"github.com/attestantio/vouch/util"
"github.com/pkg/errors"
)
// AttestationData provides the first attestation data from a number of beacon nodes.
func (s *Service) AttestationData(ctx context.Context, slot phase0.Slot, committeeIndex phase0.CommitteeIndex) (*phase0.AttestationData, error) {
started := time.Now()
log := util.LogWithID(ctx, log, "strategy_id")
// We create a cancelable context with a timeout. When a provider responds we cancel the context to cancel the other requests.
ctx, cancel := context.WithTimeout(ctx, s.timeout)
respCh := make(chan *phase0.AttestationData, 1)
for name, provider := range s.attestationDataProviders {
go func(ctx context.Context, name string, provider eth2client.AttestationDataProvider, ch chan *phase0.AttestationData) {
log := log.With().Str("provider", name).Uint64("slot", uint64(slot)).Logger()
attestationData, err := provider.AttestationData(ctx, slot, committeeIndex)
s.clientMonitor.ClientOperation(name, "attestation data", err == nil, time.Since(started))
if err != nil {
log.Warn().Dur("elapsed", time.Since(started)).Err(err).Msg("Failed to obtain attestation data")
return
}
if attestationData == nil {
log.Warn().Dur("elapsed", time.Since(started)).Err(err).Msg("Returned empty attestation data")
return
}
log.Trace().Dur("elapsed", time.Since(started)).Msg("Obtained attestation data")
ch <- attestationData
}(ctx, name, provider, respCh)
}
select {
case <-ctx.Done():
cancel()
log.Warn().Msg("Failed to obtain attestation data before timeout")
return nil, errors.New("failed to obtain attestation data before timeout")
case attestationData := <-respCh:
cancel()
return attestationData, nil
}
}