parameter_events.cpp

// Copyright 2015 Open Source Robotics Foundation, Inc.
//
// 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.

#include <chrono>
#include <memory>
#include <sstream>

#include "rclcpp/rclcpp.hpp"

using namespace std::chrono_literals;

void on_parameter_event(
  const rcl_interfaces::msg::ParameterEvent::SharedPtr event, rclcpp::Logger logger)
{
  // TODO(wjwwood): The message should have an operator<<, which would replace all of this.
  std::stringstream ss;
  ss << "\nParameter event:\n new parameters:";
  for (auto & new_parameter : event->new_parameters) {
    ss << "\n  " << new_parameter.name;
  }
  ss << "\n changed parameters:";
  for (auto & changed_parameter : event->changed_parameters) {
    ss << "\n  " << changed_parameter.name;
  }
  ss << "\n deleted parameters:";
  for (auto & deleted_parameter : event->deleted_parameters) {
    ss << "\n  " << deleted_parameter.name;
  }
  ss << "\n";
  RCLCPP_INFO(logger, ss.str().c_str())
}

int main(int argc, char ** argv)
{
  // Force flush of the stdout buffer.
  setvbuf(stdout, NULL, _IONBF, BUFSIZ);

  rclcpp::init(argc, argv);

  auto node = rclcpp::Node::make_shared("parameter_events");

  // TODO(esteve): Make the parameter service automatically start with the node.
  auto parameter_service = std::make_shared<rclcpp::ParameterService>(node);

  auto parameters_client = std::make_shared<rclcpp::SyncParametersClient>(node);
  while (!parameters_client->wait_for_service(1s)) {
    if (!rclcpp::ok()) {
      RCLCPP_ERROR(node->get_logger(), "Interrupted while waiting for the service. Exiting.")
      return 0;
    }
    RCLCPP_INFO(node->get_logger(), "service not available, waiting again...")
  }

  // Setup callback for changes to parameters.
  auto sub = parameters_client->on_parameter_event(
    [node](const rcl_interfaces::msg::ParameterEvent::SharedPtr event) -> void
    {
      on_parameter_event(event, node->get_logger());
    });

  // Set several differnet types of parameters.
  auto set_parameters_results = parameters_client->set_parameters({
    rclcpp::parameter::ParameterVariant("foo", 2),
    rclcpp::parameter::ParameterVariant("bar", "hello"),
    rclcpp::parameter::ParameterVariant("baz", 1.45),
    rclcpp::parameter::ParameterVariant("foobar", true),
  });

  // Change the value of some of them.
  set_parameters_results = parameters_client->set_parameters({
    rclcpp::parameter::ParameterVariant("foo", 3),
    rclcpp::parameter::ParameterVariant("bar", "world"),
  });

  // TODO(wjwwood): Create and use delete_parameter

  rclcpp::sleep_for(100ms);

  rclcpp::spin_some(node);

  rclcpp::shutdown();

  return 0;
}