generate_parameter_library

Generate C++ or Python code for ROS 2 parameter declaration, getting, and validation using declarative YAML. The generated library contains a C++ struct with specified parameters. Additionally, dynamic parameters and custom validation are made easy.

Killer Features

• Declarative YAML syntax for ROS 2 Parameters converted into C++ or Python struct
• Declaring, Getting, Validating, and Updating handled by generated code
• Dynamic ROS 2 Parameters made easy
• Custom user-specified validator functions
• Automatically create documentation of parameters

Basic Usage

1. Create YAML parameter codegen file
2. Add parameter library generation to project
3. Use generated struct into project source code

Create yaml parameter codegen file

Write a yaml file to declare your parameters and their attributes.

src/turtlesim_parameters.yaml

turtlesim:
  background:
    r:
      type: int
      default_value: 0
      description: "Red color value for the background, 8-bit"
      validation:
        bounds<>: [0, 255]
    g:
      type: int
      default_value: 0
      description: "Green color value for the background, 8-bit"
      validation:
        bounds<>: [0, 255]
    b:
      type: int
      default_value: 0
      description: "Blue color value for the background, 8-bit"
      validation:
        bounds<>: [0, 255]

Add parameter library generation to project

package.xml

<depend>generate_parameter_library</depend>

CMakeLists.txt

find_package(generate_parameter_library REQUIRED)

generate_parameter_library(
  turtlesim_parameters # cmake target name for the parameter library
  src/turtlesim_parameters.yaml # path to input yaml file
)

add_executable(minimal_node src/turtlesim.cpp)
target_link_libraries(minimal_node PRIVATE
  rclcpp::rclcpp
  turtlesim_parameters
)

install(TARGETS minimal_node turtlesim_parameters
  EXPORT ${PROJECT_NAME}Targets)
ament_export_targets(${PROJECT_NAME}Targets HAS_LIBRARY_TARGET)

setup.py

from generate_parameter_library_py.setup_helper import generate_parameter_module

generate_parameter_module(
  "turtlesim_parameters", # python module name for parameter library
  "turtlesim/turtlesim_parameters.yaml", # path to input yaml file
)

Use generated struct in project source code

src/turtlesim.cpp

```c++ #include <rclcpp/rclcpp.hpp> #include <turtlesim/turtlesim_parameters.hpp> // you can also use the deprecated #include “turtlesim_parameters.hpp”

int main(int argc, char * argv[]) { rclcpp::init(argc, argv); auto node = std::make_shared<rclcpp::Node>(“turtlesim”); auto param_listener = std::make_shared<turtlesim::ParamListener>(node); auto params = param_listener->get_params();

auto color = params.background; RCLCPP_INFO(node->get_logger(), “Background color (r,g,b): %d, %d, %d”, color.r, color.g, color.b);

File truncated at 100 lines see the full file

Any contribution that you make to this repository will be under the 3-Clause BSD License, as dictated by that license.