Improve push channel to detect when not all data has been received (#157

)

* test: add tests for auto-restarting a push channel

* fix: push channel monitor watch for accept and complete events

impl/impl.go

@@ -93,29 +93,9 @@ func ChannelRemoveTimeout(timeout time.Duration) DataTransferOption {
 
 // PushChannelRestartConfig sets the configuration options for automatically
 // restarting push channels
-// - interval is the time over which minBytesSent must have been sent
-// - checksPerInterval is the number of times to check per interval
-// - minBytesSent is the minimum amount of data that must have been sent over
-//   the interval
-// - restartBackoff is the time to wait before checking again for restarts
-// - maxConsecutiveRestarts is the maximum number of restarts in a row to
-//   attempt where no data is transferred. When the limit is reached the
-//   channel is closed.
-func PushChannelRestartConfig(
-	interval time.Duration,
-	checksPerInterval uint32,
-	minBytesSent uint64,
-	restartBackoff time.Duration,
-	maxConsecutiveRestarts uint32,
-) DataTransferOption {
+func PushChannelRestartConfig(cfg pushchannelmonitor.Config) DataTransferOption {
 	return func(m *manager) {
-		m.pushChannelMonitorCfg = &pushchannelmonitor.Config{
-			Interval:               interval,
-			ChecksPerInterval:      checksPerInterval,
-			MinBytesSent:           minBytesSent,
-			RestartBackoff:         restartBackoff,
-			MaxConsecutiveRestarts: maxConsecutiveRestarts,
-		}
+		m.pushChannelMonitorCfg = &cfg
 	}
 }
 
@@ -318,30 +298,76 @@ func (m *manager) CloseDataTransferChannel(ctx context.Context, chid datatransfe
 	if err != nil {
 		return err
 	}
+
+	// Close the channel on the local transport
 	err = m.transport.CloseChannel(ctx, chid)
 	if err != nil {
 		log.Warnf("unable to close channel %s: %s", chid, err)
 	}
 
-	log.Infof("%s: sending close channel to %s for channel %s", m.peerID, chst.OtherPeer(), chid)
+	// Send a cancel message to the remote peer
+	log.Infof("%s: sending cancel channel to %s for channel %s", m.peerID, chst.OtherPeer(), chid)
 	err = m.dataTransferNetwork.SendMessage(ctx, chst.OtherPeer(), m.cancelMessage(chid))
 	if err != nil {
-		err = fmt.Errorf("Unable to send cancel message: %w", err)
+		err = fmt.Errorf("unable to send cancel message for channel %s to peer %s: %w",
+			chid, m.peerID, err)
 		_ = m.OnRequestDisconnected(ctx, chid)
 		log.Warn(err)
 	}
 
+	// Fire a cancel event
 	fsmerr := m.channels.Cancel(chid)
+	// If it wasn't possible to send a cancel message to the peer, return
+	// that error
 	if err != nil {
 		return err
 	}
+	// If it wasn't possible to fire a cancel event, return that error
 	if fsmerr != nil {
 		return xerrors.Errorf("unable to send cancel to channel FSM: %w", fsmerr)
 	}
 
 	return nil
 }
 
+// close an open channel and fire an error event
+func (m *manager) CloseDataTransferChannelWithError(ctx context.Context, chid datatransfer.ChannelID, cherr error) error {
+	log.Infof("close channel %s with error %s", chid, cherr)
+
+	chst, err := m.channels.GetByID(ctx, chid)
+	if err != nil {
+		return err
+	}
+
+	// Cancel the channel on the local transport
+	err = m.transport.CloseChannel(ctx, chid)
+	if err != nil {
+		log.Warnf("unable to close channel %s: %s", chid, err)
+	}
+
+	// Try to send a cancel message to the remote peer. It's quite likely
+	// we aren't able to send the message to the peer because the channel
+	// is already in an error state, which is probably because of connection
+	// issues, so if we cant send the message just log a warning.
+	log.Infof("%s: sending cancel channel to %s for channel %s", m.peerID, chst.OtherPeer(), chid)
+	err = m.dataTransferNetwork.SendMessage(ctx, chst.OtherPeer(), m.cancelMessage(chid))
+	if err != nil {
+		// Just log a warning here because it's important that we fire the
+		// error event with the original error so that it doesn't get masked
+		// by subsequent errors.
+		log.Warnf("unable to send cancel message for channel %s to peer %s: %w",
+			chid, m.peerID, err)
+	}
+
+	// Fire an error event
+	err = m.channels.Error(chid, cherr)
+	if err != nil {
+		return xerrors.Errorf("unable to send error %s to channel FSM: %w", cherr, err)
+	}
+
+	return nil
+}
+
 // pause a running data transfer channel
 func (m *manager) PauseDataTransferChannel(ctx context.Context, chid datatransfer.ChannelID) error {
 	log.Infof("pause channel %s", chid)