dora/examples/c++-ros2-dataflow/README.md

• cxx-ros2-dataflow Example
• • Setup
  • Running pub/sub example
  • Running service example

cxx-ros2-dataflow Example

This c++ example shows how to publish/subscribe to both ROS2 and Dora. The dataflow consists of a single node that sends random movement commands to the ROS2 turtlesim_node.

Setup

This examples requires a sourced ROS2 installation.

• To set up ROS2, follow the ROS2 installation guide.
• Don't forget to source the ROS2 setup files
• Follow tasks 1 and 2 of the ROS2 turtlesim tutorial
  • Install the turtlesim package
  • Start the turtlesim node through ros2 run turtlesim turtlesim_node

Running pub/sub example

A ROS2 client to pubish turtlesim ROS2 messages and a DORA node can subscribe and visualize it.

From terminal 1 , sourcing the ROS2 installation and start ROS2 turtlesim window

source /opt/ros/galactic/setup.bash
export RMW_IMPLEMENTATION=rmw_fastrtps_cpp
ros2 run turtlesim turtlesim_node

From terminal 2 from dora folder. Note the source command here is necessary as this allow ROS2 message types to be found and compile dynamically.

export RMW_IMPLEMENTATION=rmw_fastrtps_cpp
source /opt/ros/galactic/setup.bash
cargo run --example cxx-ros2-dataflow --features ros2-examples

And you will see the turtle move a few steps.

Running service example

The current service code example is a service client. To test with service server we can test with either ROS2 demo or ros2-client

• if using ROS2 demo the the command line is:

export RMW_IMPLEMENTATION=rmw_fastrtps_cpp
ros2 run demo_nodes_cpp add_two_ints_server

start DORA service client from another terminal

export RMW_IMPLEMENTATION=rmw_fastrtps_cpp
cargo run --example cxx-ros2-dataflow --features ros2-examples

• if using ros2-client the command line is:

export RMW_IMPLEMENTATION=rmw_fastrtps_cpp
cargo run --example=ros2_service_server

then start DORA service client from another terminal

export RMW_IMPLEMENTATION=rmw_fastrtps_cpp
cargo run --example cxx-ros2-dataflow --features ros2-examples

You can also put export RMW_IMPLEMENTATION=rmw_fastrtps_cpp into .bashrc