# 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](https://github.com/aws-deepracer/aws-deepracer-launcher).

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](https://aws.amazon.com/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](https://github.com/aws-deepracer/aws-deepracer-launcher/blob/main/getting-started.md).

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.
1. `ctrl_pkg`: The AWS DeepRacer control ROS package creates the `ctrl_node`, which is part of the core AWS DeepRacer application.
1. `sensor_fusion_pkg`: The AWS DeepRacer sensor fusion ROS package creates the `sensor_fusion_node`, which is part of the core AWS DeepRacer application.
1. `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.
1. `device_info_pkg`: The AWS DeepRacer device info ROS package creates the `device_info_node`, which is part of the core AWS DeepRacer application.
1. `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

1. Source the ROS 2 Foxy setup bash script:

        source /opt/ros/foxy/setup.bash 

1. Create a workspace directory for the package:

        mkdir -p ~/deepracer_ws
        cd ~/deepracer_ws

1. Clone the `webserver_pkg` on the AWS DeepRacer device:

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

1. Fetch unreleased dependencies:

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

1. Resolve the `webserver_pkg` dependencies:

        cd ~/deepracer_ws/aws-deepracer-webserver-pkg && rosdep install -i --from-path . --rosdistro foxy -y

1. 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

1. Source the ROS 2 Foxy setup bash script:

        source /opt/ros/foxy/setup.bash 

1. Source the setup script for the installed packages:

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

1. 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](https://github.com/aws-deepracer/aws-deepracer-launcher/blob/main/getting-started.md)