Create nav2 dynamic composition

[SteveMacenski]

Something to contain manually composed nav2 system nodes so that even though the launch system doesn't deal with component-lifecycle nodes well, we can still get the benefits of both (even if not as flexible). This will be good enough for most users as they're not going to be swapping out the task servers.

Per idea / request from Emerson in the WG meeting

[SteveMacenski]

e.x. https://github.com/ros2/demos/blob/master/composition/src/manual_composition.cpp

[NithishkumarS]

So ideally where should this composition file be located?

[SteveMacenski]

In a new package, nav2_composed_bringup (or something like that, I'm not really great with naming, feel free to propose a different one)

[gezp]

i will do this work in the next few weeks. i make a plan list at first , and any suggestions are welcome.

• fix export dependency and library : Fix export dependency and library #2521
• add argument (node_option) for Nav2 Nodes : Add argument node options #2522
• create nav2_composition package, and compose all nav2 nodes in a single main(). : create new package nav2_composition #2546
• support manually composed bringup for Nav2 (in nav2_bringup package ) : Support manual composed bringup for Nav2 applications #2555
• register nodes as components ( for dynamically composed bringup ) : Register nodes as components #2562
• support dynamic composed bringup for Nav2 : support dynamic composed bringup #2750

[gezp]

It provides a composition-based bringup method, which could replace launching Nav2 nodes separately in package nav2_bringup, so it's not necessary to create a new package nav2_composition, just put it in package nav2_bringup.

[gezp]

i try to implement dynamically composed bringup for Nav2, but i failed because of some problems, i will share my experience:

• first, i try to register Nav2 nodes as the component(for exmaple, register AmclNode : https://github.com/gezp/navigation2/blob/dynamic_composed_bringup/nav2_amcl/src/amcl_node.cpp#L1373-L1378)
• then, launch these component in ComposableNodeContainer (https://github.com/gezp/navigation2/blob/dynamic_composed_bringup/nav2_bringup/launch/composed_bringup_launch.py#L103-L167)

there are some problems about loading ROS parameters :

• the first problem: ComposableNode couldn't load ros parameter yaml file (ComposableNode.parameters with a file path does not take effect.  ros2/launch_ros#156).
  • this issue is fixing in progress ( Support both parameter file configurations for composable nodes ros2/launch_ros#259), this problem will be solved.
  • in order to avoid this problem, i load a default yaml file to parameter list (https://github.com/gezp/navigation2/blob/dynamic_composed_bringup/nav2_bringup/launch/composed_bringup_launch.py#L29-L37)
• the second problem: the internal Node of ComposableNode couldn't load any parameter
  • ComposableNode is designed for a single Node, loading ComposableNode is based on ROS service (composition_interfaces/srv/load_node), and parameters will be loaded by setting rclcpp::NodeOptions in service callback (https://github.com/ros2/rclcpp/blob/master/rclcpp_components/src/component_manager.cpp#L190), so we can't load parameter for the internal Node of ComposableNode . （maybe wrong）
  • In Nav2, some Nodes need use internal Node, for example, ControllerServer use internal Node Costmap2DROS for local_costmap.

i have no idea about how to solve the second problem, any discussion is welcome.

[gezp]

in order to solve the second problem in #2147 (comment), i try to use argument --params-file for containter Node so that the internal Node could use this argument to load parameter from file.

it still has no effect, because NodeOption of component Node uses use_global_arguments(false) to disable global arguments (https://github.com/ros2/rclcpp/blob/master/rclcpp_components/src/component_manager.cpp#L151), in addition, some other
arguments also has no effect for component Node, you can find some details here : ros2/rclcpp#978

[gezp]

According to https://discourse.ros.org/t/nav2-composition/22175, a large multi-threaded executor consumes higher cpu(increase 30%-50%) than a bunch of single-threaded executors in manually composed bringup of nav2.
but rclcpp_components doesn't support a bunch of single-threaded executors for run-time composition, which is important for dynamically composed bringup of nav2 . a related issue here: ros2/rclcpp#1772 .

[gezp]

in order to solve the second problem in #2147 (comment), i try to use argument --params-file for container Node so that the internal Node could use this argument to load parameter from file.

sorry, it works well , i forgot to load parameters for each component Node when i use params-file for container.

in this way, we need load component Node's parameter from ComposableNode (code block in launch file) and load internal Node's parameter from Container Node (which seems like a bit strange).

the internal Node (e.g. local_costmap) create their own rclcpp::NodeOptions, which couldn't be affected by component Node, so default use_global_arguments(true) is used by them, which could load parameters from container's argument --params-file .

[SteveMacenski]

in this way, we need load component Node's parameter from ComposableNode (code block in launch file) and load internal Node's parameter from Container Node (which seems like a bit strange).

Indeed, sounds like we still want to enable that option, but if there's a work around we can use for now, that works for me. Lets just continue to document the issue that does exist for solutions.

[SteveMacenski]

Manual composition merged!

[SteveMacenski]

Essentially done, just waiting on docs updates

[imstevenpmwyca]

in order to solve the second problem in #2147 (comment), i try to use argument --params-file for container Node so that the internal Node could use this argument to load parameter from file.

sorry, it works well , i forgot to load parameters for each component Node when i use params-file for container.

in this way, we need load component Node's parameter from ComposableNode (code block in launch file) and load internal Node's parameter from Container Node (which seems like a bit strange).

the internal Node (e.g. local_costmap) create their own rclcpp::NodeOptions, which couldn't be affected by component Node, so default use_global_arguments(true) is used by them, which could load parameters from container's argument --params-file .

Dear @gezp,
I am dealing with the exact same issue you had loading parameters from a .yaml file to a node within a Composable node.
From reading this ticket I got the idea that you found a workaround for it; I tried doing what you described in this comment (using the Container's node argument --params-file), but it doesn't seem to work for me.
My current launch file looks something like this:

_container = ComposableNodeContainer(
            name = 'name_container',
            namespace = '',
            package = 'rclcpp_components',
            executable = 'component_container',
            composable_node_descriptions=[
                  ComposableNode(
                      package = 'package_name',
                      plugin = 'plugin::plugin',
                      name = 'node_name',
                      parameters = [
                          {'use_sim_time': use_sim_time},
                          {'param1': 1},
                          ],
                      extra_arguments = [{'use_intra_process_comms': True}]
                  ),
            ],
            arguments = ['--params-file', path/to/parameters.yaml],
            output = 'both',
    )

The Composable Node is a LifecycleNode and it uses an instance of a 2D ROS costmap from nav2 like shown below. The parameters I'm trying to load from 'path/to/parameters.yaml' are actually the ones needed for the 2D ROS costmap.

costmap_ros_ = std::make_shared<nav2_costmap_2d::Costmap2DROS>("local_costmap","","ns_local");

Am I missing something? I also tried other suggestions I found like this, this and this, and while I noticed that the ComposableNode correctly gets the parameters from the .yaml file, the costmap node within doesn't. So I haven't managed to properly initialize the costmap2dros instance.

I hope you can help me with this one,
Thank you very much for your time and consideration,
Kind regards!

[gezp]

while I noticed that the ComposableNode correctly gets the parameters from the .yaml file, the costmap node within doesn't.

i guess your .yaml file for costmap is incorrect, could you show your .yaml file?

[imstevenpmwyca]

while I noticed that the ComposableNode correctly gets the parameters from the .yaml file, the costmap node within doesn't.

i guess your .yaml file for costmap is incorrect, could you show your .yaml file?

ns_local:
    local_costmap:
        ros__parameters:
            update_frequency: 10.0
            publish_frequency: 10.0
            global_frame: odom
            robot_base_frame: base_footprint
            rolling_window: True
            (...)

I'm using a .yaml file that was working before converting the node to a ComposableNode.

[gezp]

i didn't use ComposableNodeContainer to lanuch ComposableNode, so i'm not sure why it didn't work. In Nav2, i launch container as a normal node, and --params-file isn't used, maybe you could try this method:

# use this method
params = os.path.join(get_package_share_directory('xxx'),  'config', 'parameters.yaml' )
_container = ComposableNodeContainer(
            xxx
            parameters = [params]
    )
# instead of this method
#_container = ComposableNodeContainer(
#           xxx
#           arguments = ['--params-file', path/to/parameters.yaml],
#    )

[imstevenpmwyca]

i didn't use ComposableNodeContainer to lanuch ComposableNode, so i'm not sure why it didn't work. In Nav2, i launch container as a normal node, and --params-file isn't used, maybe you could try this method:

# use this method
params = os.path.join(get_package_share_directory('xxx'),  'config', 'parameters.yaml' )
_container = ComposableNodeContainer(
            xxx
            parameters = [params]
    )
# instead of this method
#_container = ComposableNodeContainer(
#           xxx
#           arguments = ['--params-file', path/to/parameters.yaml],
#    )

This did the trick, thanks a lot man!