pnichat/aws-deepracer-webserver-pkg

The DeepRacer Web Server ROS package creates the web_publisher_node which 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 DeepRacer vehicle console.

AWS DeepRacer web server package

Overview

The AWS DeepRacer web server ROS package creates the webserver_publisher_node, which is part of the core AWS DeepRacer application and launches from the deepracer_launcher. For more details about the application and its components, see the aws-deepracer-launcher repository.

This node launches a Flask application as a background thread and creates service clients and subscribers for all the services and topics 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.

License

The source code is released under Apache 2.0.

Installation

Follow these steps to install the AWS DeepRacer web server package.

Prerequisites

The AWS DeepRacer device comes with all the prerequisite packages and libraries installed to run the webserver_pkg. For more details about the preinstalled set of packages and libraries on the AWS DeepRacer device and about installing required build systems, see the 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.
2. ctrl_pkg: The AWS DeepRacer control ROS package creates the ctrl_node, which is part of the core AWS DeepRacer application.
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 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 AWS 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 webserver_pkg on the AWS DeepRacer device:

    git clone https://github.com/aws-deepracer/aws-deepracer-webserver-pkg.git
   

5. Fetch unreleased dependencies:

    cd ~/deepracer_ws/aws-deepracer-webserver-pkg
    rosws update
   

6. Resolve the webserver_pkg dependencies:

    cd ~/deepracer_ws/aws-deepracer-webserver-pkg && 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-webserver-pkg && colcon build --packages-select webserver_pkg ctrl_pkg sensor_fusion_pkg deepracer_systems_pkg device_info_pkg i2c_pkg deepracer_interfaces_pkg
   

Usage

The webserver_publisher_node provides basic system-level functionality for the AWS DeepRacer application to work. Although the node is built to work with the AWS DeepRacer application, you can run it 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 AWS 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. Source the setup script for the installed packages:

    source ~/deepracer_ws/aws-deepracer-webserver-pkg/install/setup.bash 
   

4. 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, and provides an example demonstrating how to launch the nodes independently from the core application.

from launch import LaunchDescription
from launch_ros.actions import Node

def generate_launch_description():
    return LaunchDescription([
        Node(
            package='webserver_pkg',
            namespace='webserver_pkg',
            executable='webserver_publisher_node',
            name='webserver_publisher_node'
        )
    ])

Node details

webserver_publisher_node

Subscribed topics

Topic name	Message type	Description
/deepracer_systems_pkg/software_update_pct	SoftwareUpdatePctMsg	Message with the latest software update percentage and status.

Published topics

Topic name	Message type	Description
/webserver_pkg/calibration_drive	ServoCtrlMsg	Publish a message with raw PWM values for steering angle and throttle data sent to the servo package to calibrate the car.
/webserver_pkg/manual_drive	ServoCtrlMsg	Publish a message with steering angle and throttle data sent to the servo package to move the car.

Service clients

Service name	Service type	Description
/ctrl_pkg/vehicle_state	ActiveStateSrv	Client to the vehicle state service to deactivate the current vehicle state and prepare the new mode.
/ctrl_pkg/enable_state	EnableStateSrv	Client to the enable state service to activate and deactivate the current vehicle mode.
/ctrl_pkg/get_car_cal	GetCalibrationSrv	Client to the get calibration service to get the current calibration value for the steering or throttle.
/ctrl_pkg/set_car_cal	SetCalibrationSrv	Client to the set calibration service to set the current calibration value for the steering or throttle.
/device_info_pkg/get_device_info	GetDeviceInfoSrv	Client to the get device info service to get the hardware and software version of AWS DeepRacer device and packages.
/i2c_pkg/battery_level	BatteryLevelSrv	Client to the battery level service to get the current vehicle battery level ranging from [0 to 11].
/sensor_fusion_pkg/sensor_data_status	SensorStatusCheckSrv	Client to the sensor data status service to get the sensor connection status for single camera or stereo camera and LiDAR.
/ctrl_pkg/set_car_led	SetLedCtrlSrv	Client to the set car led service to set the tail light LED values.
/ctrl_pkg/get_car_led	GetLedCtrlSrv	Client to the get car led service to get the tail light LED values.
/ctrl_pkg/get_ctrl_modes	GetCtrlModesSrv	Client to get the available modes of operation for vehicle.
/deepracer_systems_pkg/verify_model_ready	VerifyModelReadySrv	Client to the verify model service to validate if the extraction and installation of the model was successful.
/sensor_fusion_pkg/configure_lidar	LidarConfigSrv	Client to the configure LiDAR service to dynamically configure the preprocessing details for the LiDAR data before publishing.
/ctrl_pkg/model_state	ModelStateSrv	Client to the model state service to execute the load model service in a background thread.
/ctrl_pkg/is_model_loading	GetModelLoadingStatusSrv	Client to the is model loading service to detect if there is a load model operation going on right now on the device.
/deepracer_systems_pkg/console_model_action	ConsoleModelActionSrv	Client to initiate the upload and delete models action from the device console.
/deepracer_systems_pkg/software_update_check	SoftwareUpdateCheckSrv	Client to the software update check service to find out if there is a software update available for the aws-deepracer packages.
/deepracer_systems_pkg/begin_update	BeginSoftwareUpdateSrv	Client to the begin update service to initiate the update of the aws-deepracer Debian packages to the latest software version available.
/deepracer_systems_pkg/software_update_state	SoftwareUpdateStateSrv	Client to the software update state service to get the current software update state from the states [ UPDATE_UNKNOWN, UP_TO_DATE, UPDATE_AVAILABLE, UPDATE_PENDING, UPDATE_IN_PROGRESS ].
/ctrl_pkg/autonomous_throttle	NavThrottleSrv	Client to the autonomous throttle service to set the scale value to multiply to the throttle during autonomous navigation.
/deepracer_systems_pkg/get_otg_link_state	OTGLinkStateSrv	Client to the get otg link state service to get the current connection status of the micro-USB cable to the AWS DeepRacer device.

Resources

• Getting started with AWS DeepRacer OpenSource