Custom Dockerfile, base image or docker image extension for Spring Boot 3.x

With https://start.spring.io/ I created Spring Boot 3.x app with support for native image

I can build with gralde bootBuildImage

and run with docker run spring305gradlenativeimage:0.0.1-SNAPSHOT

How to use custom Dockerfile or extend this docker image with additional packages?

build.gradle :

plugins {
	id 'java'
	id 'org.springframework.boot' version '3.0.5'
	id 'io.spring.dependency-management' version '1.1.0'
	id 'org.graalvm.buildtools.native' version '0.9.20'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '17'

configurations {
	compileOnly {
		extendsFrom annotationProcessor
	}
}

repositories {
	mavenCentral()
}

dependencies {
	implementation 'org.springframework.boot:spring-boot-starter-graphql'
	implementation 'org.springframework.boot:spring-boot-starter-web'
	compileOnly 'org.projectlombok:lombok'
	developmentOnly 'org.springframework.boot:spring-boot-devtools'
	annotationProcessor 'org.projectlombok:lombok'
	testImplementation 'org.springframework.boot:spring-boot-starter-test'
	testImplementation 'org.springframework:spring-webflux'
	testImplementation 'org.springframework.graphql:spring-graphql-test'
}

tasks.named('test') {
	useJUnitPlatform()
}

P.S. I have checked https://graalvm.github.io/native-build-tools/latest/gradle-plugin.html
and https://graalvm.github.io/native-build-tools/latest/javadocs/native-gradle-plugin/org/graalvm/buildtools/gradle/dsl/NativeImageOptions.html

The bootBuildImage task is not coming from GraalVM, but from Spring Boot.
Its documentation and options can be found at https://docs.spring.io/spring-boot/docs/current/gradle-plugin/reference/htmlsingle/#build-image.
So from what I see there from a quick look I guess you need to build an own image first that contains what you want and then configure that to be used by the bootBuildImage task.

Btw. you should start with removing the obsolete relict io.spring.dependency-management and replace it by the Gradle built-in BOM support using platform(...). Even the maintainer of that plugin recommends that.

Here another link about Spring Boot and Docker:
https://spring.io/guides/topicals/spring-boot-docker/