AWS DeepRacer webserver package for the Follow the Leader (FTL) sample project

Overview

The AWS DeepRacer webserver ROS package creates the web_publisher_node, which is part of the Follow the Leader (FTL) sample project and launches from the ftl_launcher. For more information, see the Follow the Leader (FTL) sample project.

This node launches a Flask application as a background thread and creates service clients and subscribers for all the services and topics that are required by the APIs called from the AWS DeepRacer vehicle console. This node acts as an interface between the AWS DeepRacer device console and the backend ROS services. This node was extended to provide more functionalities required for the FTL sample project.

License

The source code is released under Apache 2.0.

Installation

Follow these steps to install the AWS DeepRacer webserver package for the FTL sample project.

Prerequisites

The AWS DeepRacer device comes with all the prerequisite packages and libraries installed to run the FTL sample project. For more information about the preinstalled set of packages and libraries on the AWS DeepRacer device, and about installing the required build systems, see Getting started with AWS DeepRacer OpenSource.

The webserver_pkg specifically depends on the following ROS 2 packages as build and run dependencies.

1. deepracer_interfaces_pkg*: This package contains the custom message and service type definitions used across the AWS DeepRacer core application, modified to support the FTL sample project.
2. ctrl_pkg: The AWS DeepRacer control ROS package creates the ctrl_node, which is part of the core AWS DeepRacer application, modified to support the FTL sample project.
3. sensor_fusion_pkg: The AWS DeepRacer sensor fusion ROS package creates the sensor_fusion_node, which is part of the core AWS DeepRacer application.
4. deepracer_systems_pkg: The AWS DeepRacer systems ROS package creates the software_update_node, model_loader_node, network_monitor_node, and otg_control_node, which are part of the core AWS DeepRacer application.
5. device_info_pkg: The AWS DeepRacer device info optimizer ROS package creates the device_info_node, which is part of the core AWS DeepRacer application.
6. i2c_pkg: The AWS DeepRacer I2C ROS package creates the battery_node, which is part of the core AWS DeepRacer application.

Downloading and building

Open a terminal on the DeepRacer device and run the following commands as the root user.

1. Switch to the root user before you source the ROS 2 installation:

    sudo su
   

2. Source the ROS 2 Foxy setup bash script:

    source /opt/ros/foxy/setup.bash
   

3. Create a workspace directory for the package:

    mkdir -p ~/deepracer_ws
    cd ~/deepracer_ws
   

4. Clone the entire FTL sample project on the AWS DeepRacer device:

    git clone https://github.com/aws-deepracer/aws-deepracer-follow-the-leader-sample-project.git
    cd ~/deepracer_ws/aws-deepracer-follow-the-leader-sample-project/deepracer_follow_the_leader_ws/
   

5. Fetch the unreleased dependencies:

    cd ~/deepracer_ws/aws-deepracer-follow-the-leader-sample-project/deepracer_follow_the_leader_ws/
    rosws update
   

6. Resolve the dependencies:

    cd ~/deepracer_ws/aws-deepracer-follow-the-leader-sample-project/deepracer_follow_the_leader_ws/ && apt-get update
    rosdep install -i --from-path . --rosdistro foxy -y
   

7. Build the webserver_pkg, ctrl_pkg, sensor_fusion_pkg, deepracer_systems_pkg, device_info_pkg, i2c_pkg, and deepracer_interfaces_pkg:

    cd ~/deepracer_ws/aws-deepracer-follow-the-leader-sample-project/deepracer_follow_the_leader_ws/ && colcon build --packages-select webserver_pkg ctrl_pkg sensor_fusion_pkg deepracer_systems_pkg device_info_pkg i2c_pkg deepracer_interfaces_pkg
   

Using the webserver_publisher_node

The webserver_publisher_node provides basic system-level functionality for the AWS DeepRacer application and the FTL sample project to work. Although the node is built to work with the AWS DeepRacer application and the FTL sample project, it can be run independently for development, testing, and debugging purposes.

Running the node

To launch the built webserver_publisher_node as the root user on the AWS DeepRacer device, open another terminal on the device and run the following commands as the root user.

1. Switch to the root user before you source the ROS 2 installation:

    sudo su
   

2. Navigate to the FTL workspace:

    cd ~/deepracer_ws/aws-deepracer-follow-the-leader-sample-project/deepracer_follow_the_leader_ws/
   

3. Source the ROS 2 Foxy setup bash script:

    source /opt/ros/foxy/setup.bash 
   

4. Source the setup script for the installed packages:

    source ~/deepracer_ws/aws-deepracer-follow-the-leader-sample-project/deepracer_follow_the_leader_ws/install/setup.bash 
   

5. Launch the webserver_publisher_node using the launch script:

    ros2 launch webserver_pkg webserver_pkg_launch.py
   

Launch files

The webserver_publisher_node provides the core functionality to launch the FLASK server and respond to the FLASK API calls. The webserver_pkg_launch.py included in this package provides an example demonstrating how to launch the nodes independently from the core application.

    from launch import LaunchDescription
    from launch_ros.actions import Node

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