Add tutorial on Node Interfaces Template Class

[NickTziaros]

Relevant to isuue #4924.

Created the tutorial Using the Node Interfaces Template Class (C++) in the intermediate section.
Let me know if this is what you had in mind.

• Created Using-Node-Interfaces-Template-Class
• Modified Intermediate.rst

[alsora]

I noticed people having a lot of resistance towards the templated NodeInterface class.

I would suggest to at least mention the possibility to also do something like this if you need a simple solution

    void node_info(
        rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_interface,
        rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging_interface)
    {
      RCLCPP_INFO(node_logging_interface->get_logger(), "Node name: %s", node_base_interface->get_name());
    }

[NickTziaros]

@alsora I considered mentioning this approach as well, especialy since it was also brought up in the lightning talk .

However, I thought it might be out of scope since this tutorial focuses on showcasing the Template class. I might be wrong though . I would love the input from @kscottz @Yadunund since they raised the issue.

[Yadunund]

This is great! Thanks a lot for the contributions! Left a couple suggestions to consider.

[Yadunund]

I think the example will be more powerful if we also instantiate an instance of SimpleNode and call node_info() with this object. (we can skip spinning the nodes to keep focus on API usage)

[Yadunund]

I noticed people having a lot of resistance towards the templated NodeInterface class.

I would suggest to at least mention the possibility to also do something like this if you need a simple solution

    void node_info(
        rclcpp::node_interfaces::NodeBaseInterface::SharedPtr node_base_interface,
        rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr node_logging_interface)
    {
      RCLCPP_INFO(node_logging_interface->get_logger(), "Node name: %s", node_base_interface->get_name());
    }

I think we can include this approach before highlighting the NodeInterfaces way and emphasize that the latter has some advantages including compactness, and potentially API stability if relying on ALL_RCLCPP_NODE_INTERFACES. @alsora would you agree?

[kscottz]

@NickTziaros Thanks for stepping up here! We really appreciate it.

I think the other reviewers have covered most of the required changes. I sent you two suggestions. The first one should help clarify the motivation for the tutorial. The second one is a minor change.

I'll approve on the condition that these get folded in and everyone else's concerns are mostly addressed.

[NickTziaros]

I think the example will be more powerful if we also instantiate an instance of SimpleNode and call node_info() with this object. (we can skip spinning the nodes to keep focus on API usage)

Added both a LifecycleNode annd a simple Node in the examples.

I think we can include this approach before highlighting the NodeInterfaces way and emphasize that the latter has some advantages including compactness, and potentially API stability if relying on ALL_RCLCPP_NODE_INTERFACES. @alsora would you agree?

I also creates an example on passing the node interfaces explicitely.

Thank you all for you input. I tried to incorporate the changes you asked in this last commit. Let me know what you think and how I can make this better.

[kscottz]

@Yadunund @ahcorde This LGTM. If we're all happy let's get this merged. I would like to get it out to the community ASAP.