[[using-shell-building]]
= Building

This section covers how to build a Spring Shell application.

[[native]]
== Native Support

Support for compiling _Spring Shell_ application into a _GraalVM_ binary
mostly comes from _Spring Framework_ and _Spring Boot_ where feature is
called _AOT_. Ahead of Time means that application context is prepared
during the compilation time to being ready for _GraalVM_ generation.

Building atop of _AOT_ features from a framework _Spring Shell_ has its
own _GraalVM_ configuration providing hints what should exist in
a binary. Usually trouble comes from a 3rd party libraries which doesn't
yet contain _GraalVM_ related configurations or those configurations
are incomplete.

IMPORTANT: It is requred to use _GraalVM Reachability Metadata Repository_ which
provides some missing hints for 3rd party libraries. Also you need to have
_GraalVM_ installed and `JAVA_HOME` pointing to that.

For _gradle_ add graalvm's native plugin and configure metadata repository.

[source, groovy, subs=attributes+]
----
plugins {
	id 'org.graalvm.buildtools.native' version '0.9.16'
}

graalvmNative {
	metadataRepository {
        enabled = true
	}
}
----

When gradle build is run with `./gradlew nativeCompile` you should get binary
under `build/native/nativeCompile` directory.

For `maven` use `spring-boot-starter-parent` as parent and you'll get `native`
profile which can be used to do a compilation. You need to configure metadata repository

[source, xml, subs=attributes+]
----
<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.graalvm.buildtools</groupId>
                <artifactId>native-maven-plugin</artifactId>
                <configuration>
                    <metadataRepository>
                        <enabled>true</enabled>
                    </metadataRepository>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>
</build>
----

NOTE: If you rely on `spring-boot-starter-parent` it manages `native-maven-plugin`
version which is kept up to date.

When maven build is run with `./mvnw package -Pnative` you should get binary
under `target` directory.

If everything went well this binary can be run as is instead of executing
boot application jar via jvm.