Groovy / Gradle

Deploy a Micronaut application to AWS Elastic Beanstalk

Learn how easy it is to deploy a Micronaut application to Elastic Beanstalk.

Sergio del Amo

On this guide

In this section

Getting Started

In this guide, we will create a Micronaut application written in Groovy.

You will learn how to deploy a Micronaut application to AWS Elastic Beanstalk.

AWS Elastic Beanstalk is an easy-to-use service for deploying and scaling web applications and services developed with Java.

What you will need

To complete this guide, you will need the following:

Some time on your hands
A decent text editor or IDE (e.g. IntelliJ IDEA)
JDK 21 or greater installed with JAVA_HOME configured appropriately

Solution

We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.

Download and unzip the source

Writing the Application

Create an application using the Micronaut Command Line Interface or with Micronaut Launch.

mn create-app example.micronaut.micronautguide --build=gradle --lang=groovy

Note	If you don’t specify the `--build` argument, Gradle with the Kotlin DSL is used as the build tool. If you don’t specify the `--lang` argument, Java is used as the language. If you don’t specify the `--test` argument, JUnit is used for Java and Kotlin, and Spock is used for Groovy.

The previous command creates a Micronaut application with the default package example.micronaut in a directory named micronautguide.

Setup IntelliJ IDEA to develop Micronaut Applications.

The Micronaut management dependency adds support for monitoring your application via endpoints: special URIs that return details about the health and state of your application.

Add the management dependency:

build.gradle

implementation("io.micronaut:micronaut-management")

Once you include the management dependency, a /health endpoint is exposed.

Create a test to verify it:

groovy/src/test/groovy/example/micronaut/HealthSpec.groovy

package example.micronaut

import io.micronaut.http.HttpRequest
import io.micronaut.http.client.HttpClient
import io.micronaut.http.client.annotation.Client
import io.micronaut.test.extensions.spock.annotation.MicronautTest
import jakarta.inject.Inject
import spock.lang.Specification

@MicronautTest // 
class HealthSpec extends Specification {

    @Inject
    @Client("/")
    HttpClient client // 

    void "/health responds 200"()  {
        when:
        Map m = client.toBlocking().retrieve(HttpRequest.GET("/health"), Map) // 

        then:
        noExceptionThrown()
        m
        m.containsKey("status")
        m["status"] == "UP"
    }
}

1	Annotate the class with `@MicronautTest` so the Micronaut framework will initialize the application context and the embedded server. More info.
2	Inject the `HttpClient` bean and point it to the embedded server.
3	Creating HTTP Requests is easy thanks to the Micronaut framework fluid API.

Testing the Application

To run the tests:

./gradlew test

Then open build/reports/tests/test/index.html in a browser to see the results.

Deploy to Elastic Beanstalk

Create an executable jar including all dependencies:

./gradlew shadowJar

The next screenshots illustrate the steps necessary to deploy a Micronaut application to AWS Elastic Beanstalk:

Select Java Platform.
Click the Upload button.

Upload your JAR.

Before you create the environment, click "Configure more options". If you forget, you can change this after you create the environment.

By default, Micronaut applications listen on port 8080. Elastic Beanstalk assumes that the application listens on port 5000. There are two ways to fix this discrepancy: change the port Elastic Beanstalk is configured to use, or change the port the application listens on. For this post, we will change the application port.

The easiest way to do this is to specify the MICRONAUT_SERVER_PORT environment variable in the Elastic Beanstalk environment and set the value to 5000. (The configuration property name is micronaut.server.port, but the Micronaut framework lets you specify a more environment variable-friendly name).

On the Configuration page in your environment, under Software Configuration, click the settings icon.

Now you are ready to click Create Environment.

After a few minutes, you will be able to access the /health endpoint.

Next Steps

Explore more features with Micronaut Guides.

Learn more about AWS Elastic Beanstalk.

Help with the Micronaut Framework

The Micronaut Foundation sponsored the creation of this Guide. A variety of consulting and support services are available.

License

Note	All guides are released with an Apache License 2.0 for the code and a Creative Commons Attribution 4.0 license for the writing and media (images).