Allow ROS namespaces for planning request adapters: pass a NodeHandle for their initialization

[henningkayser]

This PR adds support for running multiple planning pipelines with different configurations at the same time. The planning including planning request adapters from separate namespaces. While the configuration of the planner plugin can already be scoped by passing a child namespace to the planning pipeline, the parameters of the planning request adapters are always queried from the private node handle from within the constructor. The parameter lookup is now moved to a new virtual initialize() function (empty by default) which expects the node handle to use. The planning pipeline calls this function on all constructed planning request adapters.

[rhaschke]

From the title, I was expecting a much larger contribution, namely supporting multiple planning pipelines (and planners) in the move_group node. To clarify the contribution of this PR, I changed the title.

There are more adapters in folder moveit_ros/planning/planning_request_adapter_plugins/src that need to be adapted to the new API.

[rhaschke]

Looks better already. Adaptation of remaining default adapters is still missing 😉

[rhaschke]

Suggested change

	"Function initialize() is not implemented. All parameters should be"
	"Implementation of function initialize() is missing, thus preventing to load parameters from the passed NodeHandle / namespace."

[henningkayser]

Isn't this a bit confusing since not all adapters load parameters?

[henningkayser]

From the title, I was expecting a much larger contribution, namely supporting multiple planning pipelines (and planners) in the move_group node. To clarify the contribution of this PR, I changed the title.

I'm actually looking into this, but I think it's a first good step to be able to actually run different planning pipelines without using the MoveGroup node.

There are more adapters in folder moveit_ros/planning/planning_request_adapter_plugins/src that need to be adapted to the new API.

You mean by adding an empty initialize() implementation?

[rhaschke]

There are more adapters in folder moveit_ros/planning/planning_request_adapter_plugins/src that need to be adapted to the new API.

You mean by adding an empty initialize() implementation?

If these adapters don't use parameters: yes. The best way to validate completeness of your API change within the code base is to make initialize() abstract.

[gavanderhoorn]

From the title, I was expecting a much larger contribution, namely supporting multiple planning pipelines (and planners) in the move_group node. To clarify the contribution of this PR, I changed the title.

I'm actually looking into this, but I think it's a first good step to be able to actually run different planning pipelines without using the MoveGroup node.

@henningkayser: can you say anything about the approach you're taking / looking into?

[henningkayser]

@gavanderhoorn I didn't implement anything yet since I'm mostly accessing the core components directly. Probably the most straightforward approach would be to scope optional (or even all) planning pipeline configurations in sub-namespaces and pass the names as parameters to the MoveGroup node. Inside the MoveGroupContext we load all specified pipelines and instead of the member planning_pipeline_ we use a getter function to access the pipeline by name. The name itself should be an optional parameter inside the MotionPlanRequest to support both MoveGroupPlanService and MoveGroupAction capabilities.

[rhaschke]

There was still an adapter missing. Having added this one myself, I approve.