Skip to content

Commit

Permalink
shorter description of setting params via YAML file - added reference…
Browse files Browse the repository at this point in the history 
…s instead
  • Loading branch information
@jkaniuka
jkaniuka committed Jan 14, 2025
1 parent da0a518 commit 8a4a580
Show file tree
Hide file tree
Showing 3 changed files with 12 additions and 258 deletions.
132 changes: 5 additions & 127 deletions source/Tutorials/Beginner-Client-Libraries/Using-Parameters-In-A-Class-CPP.rst
View file
Original file line number Diff line number Diff line change
Expand Up @@ -432,139 +432,17 @@ Further outputs should show ``[INFO] [minimal_param_node]: Hello world!`` every
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Instead of listing parameters and their values in launch file, you can create a separate YAML file that will be loaded in launch file.
First, you will need to add a config directory.
Inside the ``ros2_ws/src/cpp_parameters/`` directory, create a new directory called ``config``.
In there, create a new file called ``cpp_parameters_config.yaml``.
Placing parameters in a YAML file makes it easier to organize them, for example, by assigning them to different namespaces.
You can read more about it :ref:`here <LoadingParametersFromYAMLFile>`.

.. code-block:: yaml
custom_minimal_param_node:
ros__parameters:
my_parameter: "earth"
Now, you will have to edit ``cpp_parameters_launch.py``.
Add the import statements to the top of the file and add a variable containing the path to the configuration file.
Then replace the dictionary containing the parameter name and value with a path to YAML file.

.. code-block:: Python
import os
from ament_index_python.packages import get_package_share_directory
# ...
def generate_launch_description():
config = os.path.join(
get_package_share_directory("cpp_parameters"), "config", "cpp_parameters_config.yaml"
)
return LaunchDescription(
[
Node(
# ...
parameters=[config],
)
]
)
Now open the ``CMakeLists.txt`` file. Below the lines you added earlier, add the following lines of code.

.. code-block:: console
install(
DIRECTORY config
DESTINATION share/${PROJECT_NAME}
)
Open a console and navigate to the root of your workspace, ``ros2_ws``, and build the package:

.. tabs::

.. group-tab:: Linux

.. code-block:: console
colcon build --packages-select cpp_parameters
.. group-tab:: macOS

.. code-block:: console
colcon build --packages-select cpp_parameters
.. group-tab:: Windows

.. code-block:: console
colcon build --merge-install --packages-select cpp_parameters
Then source the setup files in a new terminal:

.. tabs::

.. group-tab:: Linux

.. code-block:: console
source install/setup.bash
.. group-tab:: macOS

.. code-block:: console
. install/setup.bash
.. group-tab:: Windows

.. code-block:: console
call install/setup.bat
Now run the node using the modified version of launch file:

.. code-block:: console
ros2 launch cpp_parameters cpp_parameters_launch.py
The terminal should return the following message the first time:

.. code-block:: console
[INFO] [custom_minimal_param_node]: Hello earth!
Further outputs should show ``[INFO] [minimal_param_node]: Hello world!`` every second.

Parameter listed in ``cpp_parameters_config.yaml`` file will be set only for ``custom_minimal_param_node`` node.
If you want to indicate that the parameter ``my_parameter`` should be set on any node in any namespace, then you should use wildcards (``/**``).

.. code-block:: yaml
/**:
ros__parameters:
my_parameter: "earth"
You can also use your parameter under namespace, but it will require some changes in ``cpp_parameters_node.cpp`` file.
First, edit config file to look like the one below.

.. code-block:: yaml
custom_minimal_param_node:
my_namespace:
ros__parameters:
my_parameter: "earth"
While declaring, getting and setting parameter value inside your C++ node, you should also add namespace to parameter name and use dot as a separator.
Modify ``cpp_parameters_node.cpp`` by changing all occurrences of ``"my_parameter"`` into ``"my_namespace.my_parameter"``.
.. note::

While declaring, getting and setting parameter value inside your C++ node, you should use dot as a separator between parameter's namespace and name.

3.4 Change via passing YAML file as an argument at node startup
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As a reminder from the :ref:`tutorial about parameters <LoadParameterFileOnNodeStartup>`, you can also load parameter file at node startup.

.. code-block:: console
ros2 run cpp_parameters minimal_param_node --ros-args --params-file ~/ros2_ws/src/cpp_parameters/config/cpp_parameters_config.yaml
Return to :ref:`tutorial about parameters <LoadParameterFileOnNodeStartup>` to remind yourself, how to load parameters file at node startup using CLI.

Summary
-------
Expand Down
136 changes: 5 additions & 131 deletions source/Tutorials/Beginner-Client-Libraries/Using-Parameters-In-A-Class-Python.rst
View file
Original file line number Diff line number Diff line change
Expand Up @@ -438,143 +438,17 @@ Further outputs should show ``[INFO] [minimal_param_node]: Hello world!`` every
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Instead of listing parameters and their values in launch file, you can create a separate YAML file that will be loaded in launch file.
First, you will need to add a config directory.
Inside the ``ros2_ws/src/python_parameters/`` directory, create a new directory called ``config``.
In there, create a new file called ``python_parameters_config.yaml``.
Placing parameters in a YAML file makes it easier to organize them, for example, by assigning them to different namespaces.
You can read more about it :ref:`here <LoadingParametersFromYAMLFile>`.

.. code-block:: yaml
custom_minimal_param_node:
ros__parameters:
my_parameter: "earth"
Now, you will have to edit ``python_parameters_launch.py``.
Add the import statements to the top of the file and add a variable containing the path to the configuration file.
Then replace the dictionary containing the parameter name and value with a path to YAML file.

.. code-block:: Python
from ament_index_python.packages import get_package_share_directory
# ...
def generate_launch_description():
config = os.path.join(
get_package_share_directory("python_parameters"), "config", "python_parameters_config.yaml"
)
return LaunchDescription(
[
Node(
# ...
parameters=[config],
)
]
)
You have to also modify ``setup.py`` by adding new statement to the ``data_files`` parameter to include all YAML config files:

.. code-block:: Python
# ...
setup(
# ...
data_files=[
# ...
(os.path.join("share", package_name, "config"), glob("config/*.yaml")),
]
)
Open a console and navigate to the root of your workspace, ``ros2_ws``, and build the package:

.. tabs::

.. group-tab:: Linux

.. code-block:: console
colcon build --packages-select python_parameters
.. group-tab:: macOS

.. code-block:: console
colcon build --packages-select python_parameters
.. group-tab:: Windows

.. code-block:: console
colcon build --merge-install --packages-select python_parameters
Then source the setup files in a new terminal:

.. tabs::

.. group-tab:: Linux

.. code-block:: console
source install/setup.bash
.. group-tab:: macOS

.. code-block:: console
. install/setup.bash
.. group-tab:: Windows

.. code-block:: console
call install/setup.bat
Now run the node using the modified version of launch file:

.. code-block:: console
ros2 launch python_parameters python_parameters_launch.py
The terminal should return the following message the first time:

.. code-block:: console
[INFO] [custom_minimal_param_node]: Hello earth!
Further outputs should show ``[INFO] [minimal_param_node]: Hello world!`` every second.

Parameter listed in ``python_parameters_config.yaml`` file will be set only for ``custom_minimal_param_node`` node.
If you want to indicate that the parameter ``my_parameter`` should be set on any node in any namespace, then you should use wildcards (``/**``).

.. code-block:: yaml
/**:
ros__parameters:
my_parameter: "earth"
You can also use your parameter under namespace, but it will require some changes in ``python_parameters_node.py`` file.
First, edit config file to look like the one below.

.. code-block:: yaml
custom_minimal_param_node:
my_namespace:
ros__parameters:
my_parameter: "earth"
While declaring, getting and setting parameter value inside your Python node, you should also add namespace to parameter name and use dot as a separator.
Modify ``python_parameters_node.py`` by changing all occurrences of ``'my_parameter'`` into ``'my_namespace.my_parameter'``.
.. note::

While declaring, getting and setting parameter value inside your Python node, you should use dot as a separator between parameter's namespace and name.

3.4 Change via passing YAML file as an argument at node startup
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As a reminder from the :ref:`tutorial about parameters <LoadParameterFileOnNodeStartup>`, you can also load parameter file at node startup.

.. code-block:: console
ros2 run python_parameters minimal_param_node --ros-args --params-file ~/ros2_ws/src/python_parameters/config/python_parameters_config.yaml
Return to :ref:`tutorial about parameters <LoadParameterFileOnNodeStartup>` to remind yourself, how to load parameters file at node startup using CLI.

Summary
-------
Expand Down
2 changes: 2 additions & 0 deletions source/Tutorials/Intermediate/Launch/Using-ROS2-Launch-For-Large-Projects.rst
View file
Original file line number Diff line number Diff line change
Expand Up @@ -170,6 +170,8 @@ First, create a new file called ``turtlesim_world_1_launch.py``.
This launch file starts the ``turtlesim_node`` node, which starts the turtlesim simulation, with simulation configuration parameters that are defined and passed to the nodes.

.. _LoadingParametersFromYAMLFile:

2.2 Loading parameters from YAML file
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Expand Down

0 comments on commit 8a4a580

Please sign in to comment.