resolve_parameter_overrides.cpp

// Copyright 2021 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 "resolve_parameter_overrides.hpp"
 
#include <string>
#include <map>
#include <vector>
 
#include "rcl_yaml_param_parser/parser.h"
#include "rcpputils/scope_exit.hpp"
 
#include "rclcpp/parameter_map.hpp"
 
std::map<std::string, rclcpp::ParameterValue>
rclcpp::detail::resolve_parameter_overrides(
  const std::string & node_fqn,
  const std::vector<rclcpp::Parameter> & parameter_overrides,
  const rcl_arguments_t * local_args,
  const rcl_arguments_t * global_args)
{
  std::map<std::string, rclcpp::ParameterValue> result;
 
  // global before local so that local overwrites global
  std::array<const rcl_arguments_t *, 2> argument_sources = {global_args, local_args};
 
  // Get fully qualified node name post-remapping to use to find node's params in yaml files
 
  for (const rcl_arguments_t * source : argument_sources) {
    if (!source) {
      continue;
    }
    rcl_params_t * params = NULL;
    rcl_ret_t ret = rcl_arguments_get_param_overrides(source, &params);
    if (RCL_RET_OK != ret) {
      rclcpp::exceptions::throw_from_rcl_error(ret);
    }
    if (params) {
      auto cleanup_params = rcpputils::make_scope_exit(
        [params]() {
          rcl_yaml_node_struct_fini(params);
        });
      rclcpp::ParameterMap initial_map = rclcpp::parameter_map_from(params, node_fqn.c_str());
 
      if (initial_map.count(node_fqn) > 0) {
        // Combine parameter yaml files, overwriting values in older ones
        for (const rclcpp::Parameter & param : initial_map.at(node_fqn)) {
          result[param.get_name()] =
            rclcpp::ParameterValue(param.get_value_message());
        }
      }
    }
  }
 
  // parameter overrides passed to constructor will overwrite overrides from yaml file sources
  for (auto & param : parameter_overrides) {
    result[param.get_name()] =
      rclcpp::ParameterValue(param.get_value_message());
  }
  return result;
}