sdeleuze/demo-profile-aot

Purpose

The goal of this repository is to showcase how Spring profiles can be used with AOT. It provides both a Gradle and a Maven-based build.

Building to a native image

There are several ways to build a native image, check the reference guide for more details.

To build with GraalVM and Gradle:

./gradlew nativeCompile

or Maven:

./mvnw -Pnative native:compile

Running the application

With Gradle, you can run the native application as follows:

build/native/nativeCompile/demo-profile-aot

With Maven:

target/demo-profile-aot

Running this sample app displays the following:

Default message from application.properties

Enabling a specific Spring profile

Spring profiles are supported by native images, but you need to enable them at build time when AOT runs. AOT pre-processes your application and evaluates auto-configurations, changing the profile at runtime is therefore ignored.

You can use any Gradle feature to customize the processAot task. For instance, the following example uses a aotProfile property with a fallback on the default profile if it is not set.

tasks.withType<ProcessAot> {
    args("--spring.profiles.active=" + (project.properties["aotProfiles"] ?: "default"))
}

You can then specify the profile(s) your native application needs as part of the regular build command:

./gradlew nativeCompile -PaotProfiles=prod

Maven users can augment the existing native profile of the Spring Boot parent by exposing a similar property, as shown in the following example:

<profile>
    <id>native</id>
    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <executions>
                        <execution>
                            <id>process-aot</id>
                            <configuration>
                                <profiles>${aot.profiles}</profiles>
                            </configuration>
                        </execution>
                    </executions>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>
</profile>

With a default value set in the properties section of the build:

<properties>
    <aot.profiles>default</aot.profiles>
</properties>

Once this is in place, the profile(s) the application needs can also be specified on the command-line:

mvn -Pnative native:compile -Daot.profiles=prod

If you compile this sample application this way, you get

Hello from prod
Default message from application.properties

What can you change at runtime with the same executable?

You can run the same application in debug mode by using the following command:

build/native/nativeCompile/demo-profile-aot --debug

You can customize the log level by using the following command:

build/native/nativeCompile/demo-profile-aot -Dlogging.level.org.springframework.beans.factory.support.DefaultListableBeanFactory=debug

You can enable the local profile since it does not involve changing the beans of the application context:

build/native/nativeCompile/demo-profile-aot -Dspring.profiles.active=local

Which displays:

Customized message from application-local.properties

You can also customize a configuration property value specifying directly the property value:

build/native/nativeCompile/demo-profile-aot -Dsample.message="Customized message from the command line"

Which displays:

Customized message from the command line