Generate a shadow jar by feature, with Gradle in a Java project - gradle

Question

I try to use the java plugin feature (https://docs.gradle.org/5.3-rc-1/userguide/feature_variants.html) to declare 2 versions of the same dependency, and generate at the end, 2 jars:
java {
registerFeature('v1') {
usingSourceSet(sourceSets.main)
}
registerFeature('v2') {
usingSourceSet(sourceSets.main)
}
}
dependencies {
compileOnly project(':djobi-core')
v1Implementation(group: 'org.elasticsearch', name: 'elasticsearch-spark-13_' + scalaVersion, version:'6.2.2') {
exclude group: "org.scala-lang"
}
v2Implementation(group: 'org.elasticsearch', name: 'elasticsearch-spark-13_' + scalaVersion, version:'6.3.2') {
exclude group: "org.scala-lang"
}
}
ShadowJar {
}
But it generates only 1, is it a good way to use feature feature like this?

Answer 1

The default task shadowJar uses the runtime configuration, see the docs-
In order to shadow configurations v1 and v2 we can define two new tasks, of type ShadowJar (they need to be configured).
Actually, v1 and v2 could be defined as "normal" configurations, that is, avoiding to use the feature-variants (it is simpler; moreover when trying to use shadowJar and the v1Implementation above, we have an error (Resolving configuration 'v1Implementation' directly is not allowed).
See the edited example below; it can be built with gradle shadowJar1 shadowJar2.
buildscript {
repositories {
maven {
url "https://plugins.gradle.org/m2/"
}
}
dependencies {
classpath "com.github.jengelman.gradle.plugins:shadow:5.0.0"
}
}
apply plugin: "com.github.johnrengelman.shadow"
apply plugin: 'java'
repositories {
maven {
url "https://plugins.gradle.org/m2/"
}
mavenCentral()
}
configurations {
v1 {
extendsFrom(implementation)
}
v2 {
extendsFrom(implementation)
}
}
dependencies {
// tweaking deps here
v1('ant:ant:1.6')
v2('junit:junit:4.12')
}
task shadowJar1(type: com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar ) {
classifier = 'v1'
configurations=[project.configurations.v1]
}
task shadowJar2(type: com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar ) {
classifier = 'v2'
configurations=[project.configurations.v2]
}