Document node parameters and switch to config-file based launch

CMakeLists.txt

@@ -223,6 +223,17 @@ install(DIRECTORY
 # Launch Block [END] #
 ######################
 
+#########################
+# Config Block [BEGIN] #
+# vvvvvvvvvvvvvvvvvvvvv #
+install(DIRECTORY
+        config
+        DESTINATION share/${PROJECT_NAME}/
+)
+# ^^^^^^^^^^^^^^^^^^^ #
+# Config Block [END] #
+#######################
+
 #########################
 # Scripts Block [BEGIN] #
 # vvvvvvvvvvvvvvvvvvvvv #

README.md

@@ -4,20 +4,44 @@
 > Repository for this module: https://github.com/SmartArmStack/sas_common. <br/>
 > More information about SmartArmStack is available in https://smartarmstack.github.io/.
 
-## ROS 2 Nodes
+## ROS 2 Nodes & Parameters
 
 Example implementations are located in the `src/examples/` directory. The package also includes a Python wrapper test script in the `scripts/` directory.
 
+The `sas_common_ros2_parameter_test_node` is launched through `sas_common_ros2_parameter_test_launch.py`, which loads parameters from `config/config.yaml` (pass a different file with `config_file:=/path/to/config.yaml`).
+
 ```bash
-docker run --rm murilomarinho/sas:jazzy bash -c "ros2 run sas_common sas_object_test_node"
+ros2 run sas_common sas_object_test_node
 ```
 
-### sas_common_ros2_parameter_test_node
+### Node: `sas_common_ros2_parameter_test_node`
+
+| Property | Value |
+|---|---|
+| **Executable** | `sas_common_ros2_parameter_test_node` |
+| **ROS node name** | `sas_common_ros2_parameter_test` (set by the `name` launch argument of `sas_common_ros2_parameter_test_launch.py`) |
+| **Description** | Example/test node demonstrating the behaviour of `sas::get_ros_parameter`. It validates ROS 2 parameter parsing, including the package-specific handling of empty lists encoded as `["EMPTY_LIST"]`. |
+
+#### Parameters
+
+All eight parameters are optional — an absent vector parameter defaults to an empty list.
 
-This example and test node demonstrates the behaviour of `sas::get_ros_parameter`. It is intended to validate ROS 2 parameter parsing, including the package-specific handling of empty lists encoded as `["EMPTY_LIST"]`.
+| Parameter | Type | Mandatory / Optional | Default | Purpose |
+|---|---|---|---|---|
+| `empty_string_vector` | string array | Optional | `[]` (empty) | Exercises the `["EMPTY_LIST"]` marker for an empty string vector |
+| `empty_integer_vector` | integer array | Optional | `[]` (empty) | Exercises the `["EMPTY_LIST"]` marker for an empty integer vector |
+| `empty_double_vector` | double array | Optional | `[]` (empty) | Exercises the `["EMPTY_LIST"]` marker for an empty double vector |
+| `empty_bool_vector` | boolean array | Optional | `[]` (empty) | Exercises the `["EMPTY_LIST"]` marker for an empty boolean vector |
+| `string_vector` | string array | Optional | `[]` (empty) | A non-empty string vector to test parsing |
+| `integer_vector` | integer array | Optional | `[]` (empty) | A non-empty integer vector to test parsing |
+| `double_vector` | double array | Optional | `[]` (empty) | A non-empty double vector to test parsing |
+| `bool_vector` | boolean array | Optional | `[]` (empty) | A non-empty boolean vector to test parsing |
 
-> [!NOTE]
-> Use `sas_common_ros2_parameter_test_launch.py` to evaluate this node.
+#### Sample launch
+
+```bash
+ros2 launch sas_common sas_common_ros2_parameter_test_launch.py
+```
 
 ### sas_object_test_node
 
@@ -53,7 +77,7 @@ docker run --rm murilomarinho/sas:jazzy bash -c "ros2 launch sas_common sas_comm
 
 ### sas_common_ros2_parameter_test_launch.py
 
-This launch file starts `sas_common_ros2_parameter_test_node` with a predefined set of parameters. It is designed to test ROS 2 parameter parsing, including the handling of empty lists encoded as `["EMPTY_LIST"]`.
+This launch file starts `sas_common_ros2_parameter_test_node`, loading its parameters from `config/config.yaml` (or a file of your choice via `config_file:=/path/to/config.yaml`). It is designed to test ROS 2 parameter parsing, including the handling of empty lists encoded as `["EMPTY_LIST"]`.
 
 ```bash
 ros2 launch sas_common sas_common_ros2_parameter_test_launch.py

config/config.yaml

@@ -0,0 +1,67 @@
+# Parameters for the sas_common nodes.
+#
+# Each top-level block is keyed by the ROS node name and is loaded by the
+# corresponding launch file via its `config_file` argument.
+
+# sas_common_ros2_parameter_test (example/test node)
+#
+# Demonstrates the behaviour of `sas::get_ros_parameter`, including the
+# package-specific handling of empty lists encoded as `["EMPTY_LIST"]`.
+# All eight parameters are optional: an absent vector parameter defaults to an
+# empty list.
+sas_common_ros2_parameter_test:
+  ros__parameters:
+    empty_string_vector:
+    - EMPTY_LIST
+    empty_integer_vector:
+    - EMPTY_LIST
+    empty_double_vector:
+    - EMPTY_LIST
+    empty_bool_vector:
+    - EMPTY_LIST
+    string_vector:
+    - a
+    - b
+    - c
+    - d
+    - e
+    - f
+    integer_vector:
+    - 1
+    - 2
+    - 3
+    - 4
+    - 5
+    - 6
+    - 7
+    - 8
+    - 9
+    - 10
+    double_vector:
+    - 11.0
+    - 12.0
+    - 13.0
+    - 14.0
+    - 15.0
+    - 16.0
+    - 17.0
+    - 18.0
+    - 19.0
+    - 20.0
+    bool_vector:
+    - false
+    - true
+    - true
+    - false
+    - true
+    - true
+    - true
+    - true
+    - false
+    - true
+    - true
+    - false
+    - true
+    - false
+    - true
+    - true

launch/sas_common_ros2_parameter_test_launch.py

@@ -1,30 +1,45 @@
 """Launch file used to run the ros2 parameter test node for sas_common.
 
 This launch description starts the `sas_common_ros2_parameter_test_node` with
-pre-configured parameters used to exercise the special EMPTY_LIST handling for
-vector parameters.
+parameters loaded from a YAML configuration file. The parameters exercise the
+special EMPTY_LIST handling for vector parameters.
+
+Pass a different file with ``config_file:=/path/to/config.yaml``.
 """
 
+import os.path
+
+from ament_index_python.packages import get_package_share_directory
 from launch import LaunchDescription
+from launch.actions import DeclareLaunchArgument
+from launch.substitutions import LaunchConfiguration
 from launch_ros.actions import Node
 
+
 def generate_launch_description():
+    """Launch the sas_common ROS2 parameter test node.
+
+    Parameters are loaded from a YAML configuration file. Pass a different
+    file with ``config_file:=/path/to/config.yaml``.
+    """
+    name = LaunchConfiguration('name')
+    config_file = LaunchConfiguration('config_file')
+
     return LaunchDescription([
+        DeclareLaunchArgument(
+            'name',
+            default_value='sas_common_ros2_parameter_test'
+        ),
+        DeclareLaunchArgument(
+            'config_file',
+            default_value=os.path.join(get_package_share_directory('sas_common'), 'config', 'config.yaml')
+        ),
         Node(
             package='sas_common',
             executable='sas_common_ros2_parameter_test_node',
-            name='sas_common_ros2_parameter_test',
+            name=name,
             output='screen',
-            parameters=[{
-                "empty_string_vector": ["EMPTY_LIST"],
-                "empty_integer_vector":  ["EMPTY_LIST"],
-                "empty_double_vector":  ["EMPTY_LIST"],
-                "empty_bool_vector":  ["EMPTY_LIST"],
-                "string_vector": ["a","b","c","d","e","f"],
-                "integer_vector":  [1,2,3,4,5,6,7,8,9,10],
-                "double_vector":  [11.0,12.0,13.0,14.0,15.0,16.0,17.0,18.0,19.0,20.0],
-                "bool_vector":  [False,True,True,False,True,True,True,True,False,True,True,False,True,False,True,True],
-            }]
+            parameters=[config_file]
         )
     ])