fetch string from output substitution object for foxy

realsense2_camera/launch/rs_launch.py

@@ -98,14 +98,22 @@ def yaml_to_dict(path_to_yaml):
 def launch_setup(context, params, param_name_suffix=''):
     _config_file = LaunchConfiguration('config_file' + param_name_suffix).perform(context)
     params_from_file = {} if _config_file == "''" else yaml_to_dict(_config_file)
+
+    _output = LaunchConfiguration('output' + param_name_suffix)
+    if(os.getenv('ROS_DISTRO') == 'foxy'):
+        # Foxy doesn't support output as substitution object (LaunchConfiguration object)
+        # but supports it as string, so we fetch the string from this substitution object
+        # see related PR that was merged for humble, iron, rolling: https://github.com/ros2/launch/pull/577
+        _output = context.perform_substitution(_output)
+
     return [
         launch_ros.actions.Node(
             package='realsense2_camera',
             namespace=LaunchConfiguration('camera_namespace' + param_name_suffix),
             name=LaunchConfiguration('camera_name' + param_name_suffix),
             executable='realsense2_camera_node',
             parameters=[params, params_from_file],
-            output=LaunchConfiguration('output' + param_name_suffix),
+            output=_output,
             arguments=['--ros-args', '--log-level', LaunchConfiguration('log_level' + param_name_suffix)],
             emulate_tty=True,
             )