Golang pb.Message類代碼示例

// SendRequest sends the request to each remote sequentially (randomized order),
// stopping after the first successful response. If all fail, returns the last
// error.
func (px *standard) SendRequest(ctx context.Context, m *dhtpb.Message) (*dhtpb.Message, error) {
	var err error
	for _, remote := range sortedByKey(px.remoteIDs, m.GetKey()) {
		var reply *dhtpb.Message
		reply, err = px.sendRequest(ctx, m, remote) // careful don't redeclare err!
		if err != nil {
			continue
		}
		return reply, nil // success
	}
	return nil, err // NB: returns the last error
}

func getRoutingProviders(ds datastore.Datastore, k string) ([]*dhtpb.Message_Peer, error) {
	e := log.EventBegin(context.Background(), "getProviders")
	defer e.Done()
	var providers []*dhtpb.Message_Peer
	if v, err := ds.Get(providerKey(k)); err == nil {
		if data, ok := v.([]byte); ok {
			var msg dhtpb.Message
			if err := proto.Unmarshal(data, &msg); err != nil {
				return nil, err
			}
			providers = append(providers, msg.GetProviderPeers()...)
		}
	}
	return providers, nil
}

// SendMessage sends message to each remote sequentially (randomized order),
// stopping after the first successful response. If all fail, returns the last
// error.
func (px *standard) SendMessage(ctx context.Context, m *dhtpb.Message) error {
	var err error
	var numSuccesses int
	for _, remote := range sortedByKey(px.remoteIDs, m.GetKey()) {
		if err = px.sendMessage(ctx, m, remote); err != nil { // careful don't re-declare err!
			continue
		}
		numSuccesses++
		switch m.GetType() {
		case dhtpb.Message_ADD_PROVIDER, dhtpb.Message_PUT_VALUE:
			if numSuccesses < replicationFactor {
				continue
			}
		}
		return nil // success
	}
	return err // NB: returns the last error
}

func putRoutingProviders(ds datastore.Datastore, k string, newRecords []*dhtpb.Message_Peer) error {
	log.Event(context.Background(), "putRoutingProviders")
	oldRecords, err := getRoutingProviders(ds, k)
	if err != nil {
		return err
	}
	mergedRecords := make(map[string]*dhtpb.Message_Peer)
	for _, provider := range oldRecords {
		mergedRecords[provider.GetId()] = provider // add original records
	}
	for _, provider := range newRecords {
		mergedRecords[provider.GetId()] = provider // overwrite old record if new exists
	}
	var protomsg dhtpb.Message
	protomsg.ProviderPeers = make([]*dhtpb.Message_Peer, 0, len(mergedRecords))
	for _, provider := range mergedRecords {
		protomsg.ProviderPeers = append(protomsg.ProviderPeers, provider)
	}
	data, err := proto.Marshal(&protomsg)
	if err != nil {
		return err
	}
	return ds.Put(providerKey(k), data)
}

func (s *Server) handleMessage(
	ctx context.Context, p peer.ID, req *dhtpb.Message) (peer.ID, *dhtpb.Message) {

	defer log.EventBegin(ctx, "routingMessageReceived", req, p).Done()

	var response = dhtpb.NewMessage(req.GetType(), req.GetKey(), req.GetClusterLevel())
	switch req.GetType() {

	case dhtpb.Message_GET_VALUE:
		rawRecord, err := getRoutingRecord(s.routingBackend, req.GetKey())
		if err != nil {
			return "", nil
		}
		response.Record = rawRecord
		return p, response

	case dhtpb.Message_PUT_VALUE:
		// FIXME: verify complains that the peer's ID is not present in the
		// peerstore. Mocknet problem?
		// if err := verify(s.peerstore, req.GetRecord()); err != nil {
		// 	log.Event(ctx, "validationFailed", req, p)
		// 	return "", nil
		// }
		putRoutingRecord(s.routingBackend, req.GetKey(), req.GetRecord())
		return p, req

	case dhtpb.Message_FIND_NODE:
		p := s.peerstore.PeerInfo(peer.ID(req.GetKey()))
		pri := []dhtpb.PeerRoutingInfo{
			{
				PeerInfo: p,
				// Connectedness: TODO
			},
		}
		response.CloserPeers = dhtpb.PeerRoutingInfosToPBPeers(pri)
		return p.ID, response

	case dhtpb.Message_ADD_PROVIDER:
		for _, provider := range req.GetProviderPeers() {
			providerID := peer.ID(provider.GetId())
			if providerID == p {
				store := []*dhtpb.Message_Peer{provider}
				storeProvidersToPeerstore(s.peerstore, p, store)
				if err := putRoutingProviders(s.routingBackend, req.GetKey(), store); err != nil {
					return "", nil
				}
			} else {
				log.Event(ctx, "addProviderBadRequest", p, req)
			}
		}
		return "", nil

	case dhtpb.Message_GET_PROVIDERS:
		providers, err := getRoutingProviders(s.routingBackend, req.GetKey())
		if err != nil {
			return "", nil
		}
		response.ProviderPeers = providers
		return p, response

	case dhtpb.Message_PING:
		return p, req
	default:
	}
	return "", nil
}