Installing features from Maven dependencies in Open Liberty 18.0.0.2

Open Liberty 18.0.0.2 is available in several runtime packages, including as a kernel without any runtime features. With the latest releases of the Liberty Maven and Gradle plugins, you can install features to build up the runtime with exactly what you need. This can be done simply by adding feature dependencies in your build. The feature dependencies also provide the relevant dependencies for compiling your application, so there is no longer any need to add Liberty API, SPI, or Java specification dependencies.

The runtime kernel

If you’re using Maven, here are the coordinates for the runtime kernel:

<assemblyArtifact>
  <groupId>io.openliberty</groupId>
  <artifactId>openliberty-kernel</artifactId>
  <version>18.0.0.2</version>
  <type>zip</type>
</assemblyArtifact>

For Gradle:

dependencies {
   libertyRuntime 'io.openliberty:openliberty-kernel:18.0.0.2'
}

Dependencies

The Open Liberty 18.0.0.2 features are available on Maven Central under the io.openliberty.features groupId. When features are listed as dependencies, they will be installed by the Maven or Gradle plugin as well as provide Liberty API, SPI, and Java specification dependencies for compilation. Features can also continue to be listed as before in the plugin configuration/attributes or in the server.xml file, in which case those features will also be retrieved from Maven Central for installation. As with all Maven dependencies, the features that are retrieved from Maven or Gradle will be stored locally allowing for offline builds.

Maven

The features-bom artifact provides the bill of materials (BOM) for each release version, and can be imported in the dependencyManagement section. This allows each feature to be listed in the dependencies section without needing to specify the version.

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>io.openliberty.features</groupId>
                <artifactId>features-bom</artifactId>
                <version>18.0.0.2</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>io.openliberty.features</groupId>
            <artifactId>jaxrs-2.1</artifactId>
            <type>esa</type>
            <scope>provided</scope>
        </dependency>
    </dependencies>

Gradle

Use the libertyFeature dependency configuration to install features. If you are using the java plugin, then the libertyFeature configuration extends from the java plugin’s compileOnly configuration to provide Liberty API, SPI, and Java specification dependencies as well.

dependencies {
   libertyFeature 'io.openliberty.features:jaxrs-2.1:18.0.0.2'
}

Putting it all together

Now that we’ve introduced the various parts, here’s how they fit together.

Maven

With Maven, import the BOM, specify feature dependencies, and configure the plugin with the install-server and install-feature goals.

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    ...
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>io.openliberty.features</groupId>
                <artifactId>features-bom</artifactId>
                <version>18.0.0.2</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>io.openliberty.features</groupId>
            <artifactId>jaxrs-2.1</artifactId>
            <type>esa</type>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>net.wasdev.wlp.maven.plugins</groupId>
                <artifactId>liberty-maven-plugin</artifactId>
                <version>2.5</version>
                <executions>
                    <execution>
                        <id>install-server</id>
                        <phase>prepare-package</phase>
                        <goals>
                            <goal>install-server</goal>
                        </goals>
                        <configuration>
                            <assemblyArtifact>
                                <groupId>io.openliberty</groupId>
                                <artifactId>openliberty-kernel</artifactId>
                                <version>18.0.0.2</version>
                                <type>zip</type>
                            </assemblyArtifact>
                        </configuration>
                    </execution>
                    <execution>
                        <id>install-feature</id>
                        <phase>prepare-package</phase>
                        <goals>
                            <goal>install-feature</goal>
                        </goals>
                        <configuration>
                            <features>
                                <acceptLicense>true</acceptLicense>
                            </features>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

Gradle

With Gradle, specify the libertyRuntime and libertyFeature dependencies.

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath group: 'net.wasdev.wlp.gradle.plugins', name: 'liberty-gradle-plugin', version: '2.5'
    }
}

apply plugin: 'liberty'

repositories {
    mavenCentral()
}

dependencies {
   libertyRuntime 'io.openliberty:openliberty-kernel:18.0.0.2'
   libertyFeature 'io.openliberty.features:jaxrs-2.1:18.0.0.2'
}

liberty {
    server {
        features {
            acceptLicense = true
        }
    }
}

Further reading

For more details on installing features from dependencies, refer to the readmes of the install-feature Maven goal or installFeature Gradle task.

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