service_client.hpp

// Copyright (c) 2018 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#ifndef NAV2_UTIL__SERVICE_CLIENT_HPP_
#define NAV2_UTIL__SERVICE_CLIENT_HPP_
 
#include <string>
 
#include "rclcpp/rclcpp.hpp"
 
namespace nav2_util
{
 
template<class ServiceT, typename NodeT = rclcpp::Node::SharedPtr>
class ServiceClient
{
public:
  explicit ServiceClient(
    const std::string & service_name,
    const NodeT & provided_node)
  : service_name_(service_name), node_(provided_node)
  {
    callback_group_ = node_->create_callback_group(
      rclcpp::CallbackGroupType::MutuallyExclusive,
      false);
    callback_group_executor_.add_callback_group(callback_group_, node_->get_node_base_interface());
    client_ = node_->template create_client<ServiceT>(
      service_name,
      rclcpp::SystemDefaultsQoS(),
      callback_group_);
  }
 
  using RequestType = typename ServiceT::Request;
  using ResponseType = typename ServiceT::Response;
 
  typename ResponseType::SharedPtr invoke(
    typename RequestType::SharedPtr & request,
    const std::chrono::nanoseconds timeout = std::chrono::nanoseconds(-1))
  {
    while (!client_->wait_for_service(std::chrono::seconds(1))) {
      if (!rclcpp::ok()) {
        throw std::runtime_error(
                service_name_ + " service client: interrupted while waiting for service");
      }
      RCLCPP_INFO(
        node_->get_logger(), "%s service client: waiting for service to appear...",
        service_name_.c_str());
    }
 
    RCLCPP_DEBUG(
      node_->get_logger(), "%s service client: send async request",
      service_name_.c_str());
    auto future_result = client_->async_send_request(request);
 
    if (callback_group_executor_.spin_until_future_complete(future_result, timeout) !=
      rclcpp::FutureReturnCode::SUCCESS)
    {
      // Pending request must be manually cleaned up if execution is interrupted or timed out
      client_->remove_pending_request(future_result);
      throw std::runtime_error(service_name_ + " service client: async_send_request failed");
    }
 
    return future_result.get();
  }
 
  bool invoke(
    typename RequestType::SharedPtr & request,
    typename ResponseType::SharedPtr & response)
  {
    while (!client_->wait_for_service(std::chrono::seconds(1))) {
      if (!rclcpp::ok()) {
        throw std::runtime_error(
                service_name_ + " service client: interrupted while waiting for service");
      }
      RCLCPP_INFO(
        node_->get_logger(), "%s service client: waiting for service to appear...",
        service_name_.c_str());
    }
 
    RCLCPP_DEBUG(
      node_->get_logger(), "%s service client: send async request",
      service_name_.c_str());
    auto future_result = client_->async_send_request(request);
 
    if (callback_group_executor_.spin_until_future_complete(future_result) !=
      rclcpp::FutureReturnCode::SUCCESS)
    {
      // Pending request must be manually cleaned up if execution is interrupted or timed out
      client_->remove_pending_request(future_result);
      return false;
    }
 
    response = future_result.get();
    return response.get();
  }
 
  bool wait_for_service(const std::chrono::nanoseconds timeout = std::chrono::nanoseconds::max())
  {
    return client_->wait_for_service(timeout);
  }
 
  std::string getServiceName()
  {
    return service_name_;
  }
 
protected:
  std::string service_name_;
  NodeT node_;
  rclcpp::CallbackGroup::SharedPtr callback_group_;
  rclcpp::executors::SingleThreadedExecutor callback_group_executor_;
  typename rclcpp::Client<ServiceT>::SharedPtr client_;
};
 
}  // namespace nav2_util
 
#endif  // NAV2_UTIL__SERVICE_CLIENT_HPP_