Rockcraft Build Plugins

Builds Ubuntu ROCK image for your application using Gradle or Maven. The plugin requires rockcraft installed.

How it works

The build plugins generate rockcraft.yaml in the output directory and build a rock image for your application.

The plugins provide tasks/goals to build and deploy rock image.

The parts generated are prefixed with a build system name, e.g. gradle or maven. The plugins create the following parts in rockcraft.yaml:

• <build-system>/rockcraft/runtime: e.g. maven/rockcraft/runtime or gradle/rockcraft/runtime. This part generates a Java runtime image for the application using jlink. The part finds all jar files in the target image /jars directory and generates a runtime image deployed in the /usr/jvm/java-<version>-openjdk-<arch>/ directory. It creates a symlink to java executable in /usr/bin/java.
• <build-system>/rockcraft/deps: deploys openjdk runtime dependencies.
• <build-system>/rockcraft/dump: copies build artifact into target image's /jars directory.

The rock is built using the base bare image.

To override the generated rockcraft.yaml, provide a rockcraftYaml plugin configuration property. The plugin will merge your custom configuration into the generated file.

If rockcraftYaml isn't set, the plugin checks these default locations for an override file:

• Application rock: rock/rockcraft.yaml
• Build rock: build-rock/rockcraft.yaml

Configuration Options

Name	Description
buildPackage	OpenJDK Ubuntu package used to create a runtime image, e.g. openjdk-21-jdk-headless
targetRelease	--multi-release option passed to jlink
summary	rock image summary, e.g. Spring Boot Application
description	path to the description file, e.g. README.md
command	command used for the startup service
source	Git URL of chisel-releases repository
branch	Git branch of chisel-releases repository
architectures	list of the supported architectures, e.g. amd64, arm64
slices	list of additional chisel slices to install
rockcraftYaml	path to rockcraft.yaml with the overrides for the generated rockraft.yaml
createService	create startup service (default true)
distTask	task/goal that creates application distribution that can be deployed to the container (default empty)

Gradle Plugin

Getting started

Install rockcraft: snap install rockcraft.

To use the plugin, apply the following two steps:

1. Apply the plugin

Using the plugins DSL:

Groovy

plugins {
    id 'io.github.rockcrafters.rockcraft' version '1.2.7'
}

Kotlin

plugins {
    id("io.github.rockcrafters.rockcraft") version "1.2.7"
}

Alternatively, you can use the buildscript DSL:

Groovy

buildscript {
    repositories {
        maven {
            url "https://plugins.gradle.org/m2/"
        }
    }
    dependencies {
        classpath 'io.github.rockcrafters.rockcraft:1.2.7'
    }
}
apply plugin: 'io.github.rockcrafters.rockcraft-plugin'

Kotlin

buildscript {
    repositories {
        maven {
            setUrl("https://plugins.gradle.org/m2/")
        }
    }
    dependencies {
        classpath("io.github.rockcrafters.rockcraft:1.2.7")
    }
}
apply(plugin = "io.github.rockcrafters.rockcraft")

2. Configure the container

The plugin allows setting up container summary and description, target architectures and the startup service command line.

Groovy

rockcraft {
    buildPackage = 'openjdk-21-jdk'
    targetRelease = 21
    summary = 'A ROCK summary'
    description = 'README.md'
    command = '/usr/bin/java -jar jars/application.jar'
    source = 'http://github.com/myuser/chisel-releases'
    branch = 'my-chisel-release-branch'
    slices = ['busybox_bins', 'fontconfig_config']
    architectures = ['amd64', 'arm64']
    createService = false
    rockcraftYaml = 'rockcraft.yaml'
}

Kotlin

rockcraft {
    buildPackage = "openjdk-21-jdk"
    targetRelease = 21
    summary = "A ROCK summary"
    description = "README.md"
    command = "/usr/bin/java -jar jars/application.jar"
    source = "http://github.com/myuser/chisel-releases"
    branch = "my-chisel-release-branch"
    slices("busybox_bins", "fontconfig_config")
    architectures("amd64", "arm64")
    createService = false
    setRockcraftYaml("rockcraft.yaml")
}

3. Export Dependencies

The plugin provides dependencies-export task that stores project dependencies into build/build-rock/dependences. This is equivalent to Maven dependency plugin go-offline goal. By default, the task exports all resolvable configurations of the project and buildscript. The dependenciesExport configuration allows to customize the list of exported configurations.

Groovy

dependenciesExport {
    buildScript = true
    configurations = ["runtimeClasspath", "testRuntimeClasspath"]
}

Kotlin

dependenciesExport {
    buildScript = true
    configurations("runtimeClasspath", "testRuntimeClasspath")
}

4. Create build container

The plugin provides create-build-rock and build-build-rock tasks that creates a chiselled build container. It contains a local maven repository with all the project dependencies, chiselled openjdk and Gradle installation.

Groovy

buildRockcraft {
    buildPackage = "openjdk-21-jdk"
    summary = "A ROCK summary"
    description = "README.md"
    source = "http://github.com/myuser/chisel-releases"
    branch = "my-chisel-release-branch"
    slices("busybox_bins", "fontconfig_config")
    architectures("amd64", "arm64")
    rockcraftYaml =  "rockcraft.yaml"
}

Kotlin

buildRockcraft {
    buildPackage = "openjdk-21-jdk"
    summary = "A ROCK summary"
    description = "README.md"
    source = "http://github.com/myuser/chisel-releases"
    branch = "my-chisel-release-branch"
    slices("busybox_bins", "fontconfig_config")
    architectures("amd64", "arm64")
    setRockcraftYaml("rockcraft.yaml")
}

Examples

Please see examples to try the sample projects.

Maven Plugin

Getting started

Install rockcraft: snap install rockcraft.

The plugin goals have rockcraft prefix. For example, mvn rockcraft:push-rock will attempt to build runtime image and push it to the local docker daemon.

To use the plugin, apply the following two steps:

1. Apply the plugin

Apply the plugin:

    <build>
        <plugins>
            ...
            <plugin>
                <groupId>io.github.rockcrafters</groupId>
                <artifactId>rockcraft-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <!-- creates rockcraft.yaml -->
                            <goal>create-rock</goal>
                            <!-- builds rock image -->
                            <goal>build-rock</goal>
                            <!-- pushes rock to the local docker daemon-->
                            <goal>push-rock</goal>
                            <!-- creates build container rockcraft.yaml -->
                            <goal>create-build-rock</goal>
                            <!-- builds build rock image -->
                            <goal>build-build-rock</goal>
                            <!-- pushes build rock to the local docker daemon-->
                            <goal>push-build-rock</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

2. Configure the container

The plugin supports all configuration options.

        <plugins>
            <plugin>
                <groupId>io.github.rockcrafters</groupId>
                <artifactId>rockcraft-maven-plugin</artifactId>
                ...
                <configuration>
                    <buildPackage>openjdk-17-jdk-headless</buildPackage>
                    <targetRelease>17</targetRelease>
                    <jlink>false</jlink>
                    <summary>foo</summary>
                    <description>readme.txt</description>
                    <source>https://github.com/canonical/chisel-releases</source>
                    <branch>ubuntu-24.04</branch>
                    <architectures>
                        <architecture>amd64</architecture>
                        <architecture>arm64</architecture>
                    </architectures>
                    <slices>
                        <slice>busybox_bins</slice>
                        <slice>dash_bins</slice>
                    </slices>
                </configuration>
            </plugin>
        </plugins>

3. Configure the build container (optional)

Build

        <plugins>
            <plugin>
                <groupId>io.github.rockcrafters</groupId>
                <artifactId>rockcraft-maven-plugin</artifactId>
                ...
                <configuration>
                    ...
                    <!-- allows use of artifacts in the local Maven repository in the build container, default false -->
                    <allowLocal>true</allowLocal>
                    <!-- workaround https://issues.apache.org/jira/browse/MNG-6965 - plugin will add
                         a placeholder pom and jar in place of org.codehaus.plexus:plexus-utils:1.1 -->
                    <workaroundPlexusUtils>true</workaroundPlexusUtils>
                </configuration>
            </plugin>
        </plugins>

Examples

Please see examples to try the sample projects.

Issues and Contributions

Issues can be reported to the Issue tracker.

Contributions can be submitted via Pull requests,

TODO

• Error handling (empty jar file), no main class