Web Server

This project is a client/server setup, representing data-collection for an Internet-of-Things (IoT) setup. Using SQLite as the database, and popular Rust crates for building web servers and managing data.

Brief

A company is building data-collection widget for customers. These widgets are small, low-power devices that collect data from sensors and send it to a central server. The server stores the data, and provides a web interface for customers to view their data. To achieve this I will need to:

• Build a daemon to the on the data-collectors
• Build a server to receive and store the data
• Build a web server to query and display the data

Collection Daemon

THe collection daemon has to run on small, low-power devices. I will seek to minimise the binary size, memory and CPU usage and keep network traffic to a minimum.

Collection Server

The collection server will receive data from collection daemons, and store it in a database (SQLite for now).

Web Service

Starting with a relatively minimal web-service that uses Apache E-Charts in the client to display the data. I'll use the Axum web framework, and I will use the SQLite database directly.

Overview

The data flow can be visualised as follows:

graph BT
DataCollector[Data Collector] ---> Ingestor
DataCollector2[Data Collector] ---> Ingestor
DataCollector3[Data Collector] ---> Ingestor
Ingestor ---> SQLite
WebServer[Web Server] <---> SQLite
WebClient[Web Client] <---> WebServer

Installation

To run this application you will need to have Rust installed (via RustUp).

To create and setup the db you will need to install the SQLx command-line client:

cargo install sqlx-cli

Then create and build the database:

sqlx database create
sqlx migrate run

Run

To test the shared resource (responsible for encoding and decoding the data) move into the shared directory and run the following command.

cargo test

To run the server use cargo run within the server directory. You can do the same for the collector.

You will see a steady stream of data being encoded within the collector, and the server will be receiving the data.

If the server is stopped, the collector will queue up data and send it when the sever becomes available.

When the server is active you will be able to access a webpage on http://localhost:3000/ which has the following routes:

• / - display index.html
• api/all - show all datapoints (JSON)
• api/collectors - show all collectors (JSON)
• api/collector/:uuid - show all datapoints for a given collector (JSON)
• api/collector/:uuid/shutdown - send a shutdown command to a given collector

Optimisations

Using cargo bloat and cargo tree has identified that UUID creation and sysinfo have dependencies that take up a considerable amount of space. Removing UUID creation and omitting the rayon can save some space. Potential reductions could be obtained by updating the crates being used in the project.

This project demonstrates the learnings from the fifth week of the Ardan Labs: Ultimate Rust Foundations course.