Customize Micronaut for Platform.sh


Now that your code contains all of the configuration to deploy on Platform.sh, it’s time to make your Micronaut site itself ready to run on a Platform.sh environment. There are a number of additional steps that are either required or recommended, depending on how well you want to optimize your site.

Install the Config Reader 

Platform.sh provides all information about the running environment, including how to connect to services, through environment variables. These may be accessed directly, but it is often easier to use the Config Reader library that Platform.sh provides. The Config Reader is simply a set of utilities to wrap the environment variables and make them a bit more ergonomic to work with.

Below is an example of how to install the Config Reader for Java using Maven:

<dependency>
    <groupId>sh.platform</groupId>
    <artifactId>config</artifactId>
    <version>2.2.2</version>
</dependency>

and Gradle:

compile group: 'sh.platform', name: 'config', version: '2.2.2'

.environment 

The .platform.app.yaml file on the previous page has been pulled directly from the Micronaut template. It is sufficient to deploy Micronaut on it’s own, but since Micronaut makes it possible to overwrite configurations without impacting the application itself, you might elect to rely more heavily on environment variables in it’s place.

Consider this simplified .platform.app.yaml file:

name: app

type: "java:11"

disk: 1024

hooks:
    build: build: mvn clean package
    
web:
    commands:
        start: java -jar $JAVA_OPTS $CREDENTIAL target/file.jar

On Platform.sh, we can set the environment variable JAVA_OPTS by committing a .environment file to the repository’s root. Platform.sh runs source .environment in the application root when a project starts, and when logging into the environment over SSH. That gives you a place to do extra environment variable setup prior to the application running, including modifying the system $PATH and other shell level customizations. It will allow us to define JAVA_OPTS when running on Platform.sh, but otherwise not be used during local development testing.

# .environment
export JAVA_OPTS="-Xmx$(jq .info.limits.memory /run/config.json)m -XX:+ExitOnOutOfMemoryError"