Exemplo n.º 1
0
func (px *standard) sendRequest(ctx context.Context, m *dhtpb.Message, remote peer.ID) (*dhtpb.Message, error) {
	e := log.EventBegin(ctx, "sendRoutingRequest", px.Host.ID(), remote, logging.Pair("request", m))
	defer e.Done()
	if err := px.Host.Connect(ctx, peer.PeerInfo{ID: remote}); err != nil {
		e.SetError(err)
		return nil, err
	}
	s, err := px.Host.NewStream(ProtocolSNR, remote)
	if err != nil {
		e.SetError(err)
		return nil, err
	}
	defer s.Close()
	r := ggio.NewDelimitedReader(s, inet.MessageSizeMax)
	w := ggio.NewDelimitedWriter(s)
	if err = w.WriteMsg(m); err != nil {
		e.SetError(err)
		return nil, err
	}

	response := &dhtpb.Message{}
	if err = r.ReadMsg(response); err != nil {
		e.SetError(err)
		return nil, err
	}
	// need ctx expiration?
	if response == nil {
		err := errors.New("no response to request")
		e.SetError(err)
		return nil, err
	}
	e.Append(logging.Pair("response", response))
	e.Append(logging.Pair("uuid", logging.Uuid("foo")))
	return response, nil
}
Exemplo n.º 2
0
Arquivo: bitswap.go Projeto: rht/ipget
// GetBlock attempts to retrieve a particular block from peers within the
// deadline enforced by the context.
func (bs *Bitswap) GetBlock(parent context.Context, k key.Key) (*blocks.Block, error) {

	// Any async work initiated by this function must end when this function
	// returns. To ensure this, derive a new context. Note that it is okay to
	// listen on parent in this scope, but NOT okay to pass |parent| to
	// functions called by this one. Otherwise those functions won't return
	// when this context's cancel func is executed. This is difficult to
	// enforce. May this comment keep you safe.

	ctx, cancelFunc := context.WithCancel(parent)

	ctx = logging.ContextWithLoggable(ctx, logging.Uuid("GetBlockRequest"))
	log.Event(ctx, "Bitswap.GetBlockRequest.Start", &k)
	defer log.Event(ctx, "Bitswap.GetBlockRequest.End", &k)

	defer func() {
		cancelFunc()
	}()

	promise, err := bs.GetBlocks(ctx, []key.Key{k})
	if err != nil {
		return nil, err
	}

	select {
	case block, ok := <-promise:
		if !ok {
			select {
			case <-ctx.Done():
				return nil, ctx.Err()
			default:
				return nil, errors.New("promise channel was closed")
			}
		}
		return block, nil
	case <-parent.Done():
		return nil, parent.Err()
	}
}