Air quality monitoring API written in Kotlin 🛠

Purpose

The project is a polygon for learning the art of building and testing an API.

Using the well-known ope service LUCHTMEETNET 2020 OPENAPI, I have launched the stateless service that aggregates the data, produced by LuchtmeeNet open API.

Info from Luchtmeetnet

The website Luchtmeetnet is an initiative of the Ministry of Infrastructure and the Environment, the National Institute of Public Health and the Environment (RIVM), GGD Amsterdam, EPA for the greater Rotterdam area (DCMR), the Province of Limburg, EPA's middle and western Brabant (OMWB) and EPA region Arnhem (ODRA). The website displays the measured air quality on several measuring stations in the Netherlands and the calculated air quality maps. This API grants direct access to detailed information of the stations and the measurements made there.

Motivation

Luchtmeetnet service is providing paged data over many pollutants measured by many stations every hour. My motivation is to aggregate the measurements and provide the snapshots that are helpful if you want some practical answers about the quality of air you are breathing, or if you want to know the trends of air contamination in your region.

Software Stack

• Java JDK 8+/Kotlin as main execution environment;
• Vert.X - Polyglot lightweight asynchronous event-driven platform that runs the stateless services;
• Gradle 6 as main build tool;
• Vert.X Unit and JUnit 4 as testing framework

Setup

You need to have Java 8 SDK set up.

IDE

This project was created in IntelliJ Community edition.

How to run

This project uses Gradle Wrapper. Switch to the project root directory and use one the following commands. Build the project:

$./gradlew build 

Run the Vert.X server in development mode

$./gradlew run 

Testing

Each data service is shipped with integration tests. Current framework of integration tests is built with Apache Http Client, Vert.X Unit and Junit. Integration tests of air quality monitor API are also armed with Test Retry Gradle Plugin. They are integrated with CircleCI platform.

The synchronous HTTP client is to be replaced either with REST Assured or with Vert.X Async Http client

Run integration tests using command:

$./gradlew test 

Build a fat Jar and run in production mode using command

$./gradlew shadowJar
$java -jar build/libs/app-shadow.jar

API ENDPOINTS

OpenAPI is available: airrotterdam-api

Included features

• Kotlin coroutines concurrently querying the paged responses
• Retrofit2 (+ Kotlin coroutines await() for Retrofit2 Call)
• Gradle
• Integration tests with Vert.X Unit API