Status of parameters

iluetkeb · November 30, 2017, 2:38pm

It seems that while some work has been done on using parameters, setting them is not implemented, correct?

At least, when I call "ros2param list ", I get nothing, even though the node in question has and uses parameters. (turtlebot2 kobuki_node, to be exact).

marguedas · November 30, 2017, 3:38pm

In ROS 2 the parameters are implementing within the node.
Each node can have local parameters but needs a “parameter server” to allow remote nodes to modify them. We haven’t propagated the parameter service to all our nodes as we expect it to be started automatically in he future.
You can see minimal example of node running the parameter service here

Hope this helps

karsten · November 30, 2017, 5:13pm

In a decentralized system, we’d to spawn nodes which serve as parameter
servers. The example Mikael gave shows the basic usage.
You can have a look what was done for the ros2_control implementation.

The “controller_parameter_server” is meant as a global parameters server,
which has capabilities to load params from yaml files and puts them in
their respective namespaces.
Various controllers can then fetch these values with the
remote_parameter_client.

github.com

ros-controls/ros2_controllers/blob/master/ros_controllers/src/joint_trajectory_controller.cpp

// Copyright 2017 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 "ros_controllers/joint_trajectory_controller.hpp"

#include <cassert>
#include <chrono>
#include <iterator>
#include <string>

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Status of parameters

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