Program Listing for File synchronous_service_client.hpp

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/*!*******************************************************************************************
 *  \file       synchronous_service_client.hpp
 *  \brief      Class for handling synchronous service clients in ROS2
 *              without taking care about the spin() method
 *  \authors    Miguel Fernández Cortizas
 *              Pedro Arias Pérez
 ********************************************************************************/

#ifndef AS2_CORE__SYNCHRONOUS_SERVICE_CLIENT_HPP_
#define AS2_CORE__SYNCHRONOUS_SERVICE_CLIENT_HPP_

#include <memory>
#include <string>

#include "as2_core/node.hpp"
#include "rclcpp/rclcpp.hpp"

namespace as2
{

template<class ServiceT>
class SynchronousServiceClient
{
  typedef typename ServiceT::Request RequestT;
  typedef typename ServiceT::Response ResponseT;
  std::string service_name_;
  as2::Node * node_;

  rclcpp::CallbackGroup::SharedPtr callback_group_;
  rclcpp::executors::SingleThreadedExecutor callback_group_executor_;
  std::shared_ptr<rclcpp::Client<ServiceT>> service_client_;

public:
  using SharedPtr = std::shared_ptr<SynchronousServiceClient<ServiceT>>;

  SynchronousServiceClient(std::string service_name, as2::Node * node)
  : service_name_(service_name), node_(node)
  {
    callback_group_ =
      node_->create_callback_group(rclcpp::CallbackGroupType::MutuallyExclusive, false);
    callback_group_executor_.add_callback_group(callback_group_, node_->get_node_base_interface());
    service_client_ = node_->create_client<ServiceT>(
      service_name, rmw_qos_profile_services_default, callback_group_);
  }

  bool sendRequest(const RequestT & req, ResponseT & resp, int wait_time = 0)
  {
    auto resp_ptr = std::make_shared<ResponseT>(resp);
    if (!sendRequest(std::make_shared<RequestT>(req), resp_ptr, wait_time)) {
      return false;
    }
    resp = *resp_ptr.get();
    return true;
  }

  bool sendRequest(
    const std::shared_ptr<RequestT> & req, std::shared_ptr<ResponseT> & resp, int wait_time = 0)
  {
    if (wait_time <= 0) {
      while (!service_client_->wait_for_service(std::chrono::seconds(1))) {
        if (!rclcpp::ok()) {
          RCLCPP_ERROR(node_->get_logger(), "interrupted while waiting for the service. exiting.");
          return false;
        }
        RCLCPP_INFO(
          node_->get_logger(), "service: %s not available, waiting again...",
          service_name_.c_str());
      }
    } else {
      if (!service_client_->wait_for_service(std::chrono::seconds(wait_time))) {
        if (!rclcpp::ok()) {
          RCLCPP_ERROR(node_->get_logger(), "interrupted while waiting for the service. exiting.");
          return false;
        }
        RCLCPP_WARN(
          node_->get_logger(), "service: %s not available, returning False ",
          service_name_.c_str());
        return false;
      }
    }

    auto result = service_client_->async_send_request(req);
    if (
      callback_group_executor_.spin_until_future_complete(result) !=
      rclcpp::FutureReturnCode::SUCCESS)
    {
      RCLCPP_WARN(
        node_->get_logger(), "failed to receive response from service '%s'", service_name_.c_str());
      return false;
    }

    resp = result.get();
    return true;
  }  // namespace as2

protected:
};  // namespace as2

}  // namespace as2
#endif  // AS2_CORE__SYNCHRONOUS_SERVICE_CLIENT_HPP_