Method unaryRPC

vpn/speaker.go:191–221

unaryRPC sends a request/response style RPC over the protocol, waits for the response, then returns the response

(ctx context.Context, req S)

// unaryRPC sends a request/response style RPC over the protocol, waits for the response, then
// returns the response
func (s *speaker[S, R, _]) unaryRPC(ctx context.Context, req S) (resp R, err error) {
	rpc := req.EnsureRPC()
	msgID, respCh := s.newRPC()
	rpc.MsgId = msgID
	logger := s.logger.With(slog.F("msg_id", msgID))
	select {
	case <-ctx.Done():
		return resp, ctx.Err()
	case <-s.ctx.Done():
		return resp, xerrors.Errorf("vpn protocol closed: %w", s.ctx.Err())
	case <-s.recvLoopDone:
		logger.Debug(s.ctx, "recvLoopDone while sending request")
		return resp, io.ErrUnexpectedEOF
	case s.sendCh <- req:
		logger.Debug(s.ctx, "sent rpc request", slog.F("req", req))
	}
	select {
	case <-ctx.Done():
		s.rmResponseChan(msgID)
		return resp, ctx.Err()
	case <-s.ctx.Done():
		s.rmResponseChan(msgID)
		return resp, xerrors.Errorf("vpn protocol closed: %w", s.ctx.Err())
	case <-s.recvLoopDone:
		logger.Debug(s.ctx, "recvLoopDone while waiting for response")
		return resp, io.ErrUnexpectedEOF
	case resp = <-respCh:
		logger.Debug(s.ctx, "got response", slog.F("resp", resp))
		return resp, nil
	}
}

func (s *speaker[_, R, _]) newRPC() (uint64, chan R) {
	s.mu.Lock()