prysm-pulse/beacon-chain/p2p/broadcaster.go
2020-06-09 15:40:48 -07:00

86 lines
2.6 KiB
Go

package p2p
import (
"bytes"
"context"
"fmt"
"reflect"
"github.com/gogo/protobuf/proto"
"github.com/pkg/errors"
eth "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
"github.com/prysmaticlabs/prysm/shared/hashutil"
"github.com/prysmaticlabs/prysm/shared/traceutil"
"go.opencensus.io/trace"
)
// ErrMessageNotMapped occurs on a Broadcast attempt when a message has not been defined in the
// GossipTypeMapping.
var ErrMessageNotMapped = errors.New("message type is not mapped to a PubSub topic")
const attestationSubnetTopicFormat = "/eth2/%x/beacon_attestation_%d"
// Broadcast a message to the p2p network.
func (s *Service) Broadcast(ctx context.Context, msg proto.Message) error {
ctx, span := trace.StartSpan(ctx, "p2p.Broadcast")
defer span.End()
forkDigest, err := s.forkDigest()
if err != nil {
err := errors.Wrap(err, "could not retrieve fork digest")
traceutil.AnnotateError(span, err)
return err
}
topic, ok := GossipTypeMapping[reflect.TypeOf(msg)]
if !ok {
traceutil.AnnotateError(span, ErrMessageNotMapped)
return ErrMessageNotMapped
}
return s.broadcastObject(ctx, msg, fmt.Sprintf(topic, forkDigest))
}
// BroadcastAttestation broadcasts an attestation to the p2p network.
func (s *Service) BroadcastAttestation(ctx context.Context, subnet uint64, att *eth.Attestation) error {
ctx, span := trace.StartSpan(ctx, "p2p.BroadcastAttestation")
defer span.End()
forkDigest, err := s.forkDigest()
if err != nil {
err := errors.Wrap(err, "could not retrieve fork digest")
traceutil.AnnotateError(span, err)
return err
}
return s.broadcastObject(ctx, att, attestationToTopic(subnet, forkDigest))
}
// method to broadcast messages to other peers in our gossip mesh.
func (s *Service) broadcastObject(ctx context.Context, obj interface{}, topic string) error {
_, span := trace.StartSpan(ctx, "p2p.broadcastObject")
defer span.End()
span.AddAttributes(trace.StringAttribute("topic", topic))
buf := new(bytes.Buffer)
if _, err := s.Encoding().EncodeGossip(buf, obj); err != nil {
err := errors.Wrap(err, "could not encode message")
traceutil.AnnotateError(span, err)
return err
}
if span.IsRecordingEvents() {
id := hashutil.FastSum64(buf.Bytes())
messageLen := int64(buf.Len())
span.AddMessageSendEvent(int64(id), messageLen /*uncompressed*/, messageLen /*compressed*/)
}
if err := s.pubsub.Publish(topic+s.Encoding().ProtocolSuffix(), buf.Bytes()); err != nil {
err := errors.Wrap(err, "could not publish message")
traceutil.AnnotateError(span, err)
return err
}
return nil
}
func attestationToTopic(subnet uint64, forkDigest [4]byte) string {
return fmt.Sprintf(attestationSubnetTopicFormat, forkDigest, subnet)
}