Gradle Conditional Dependencies based on Task

Question

I have some generic jdbc related code that I want to package up separately into a runnable jar with the required jdbc library already included, so there would be a separate runnable jar for each database type. The source will remain the same, but the jdbc jar packaged will be different.

For example jdbc-app-postgres.jar will contain only the postgres jdbc jar, while jdbc-app-mysql.jar will contain the mysql jdbc jar.

Is it possible to do this with tasks or anything else using gradle?

It seems like it should be possible with a custom shadowJar task and custom configurations, but as far as I can tell custom shadow jar tasks aren't correctly working with getting the full dependencies included (for example: https://github.com/johnrengelman/shadow/issues/448)

Ideally the solution would look something like, but anything that works is fine with me

configurations {
    mysql.extendsFrom implementation
}
....

task buildMysql(type: ShadowJar) {
    archiveName = "jdbc-mysql.${extension}"
    from sourceSets.main.output
    configurations = [configurations.mysql]
}

Answer 1

I actually have seemed to find a way to do this that's working

First, create your custom configuration(s) and dependencies like:

configurations {
    mysql.extendsFrom runtimeClasspath
    // etc ...

    compileClasspath.extendsFrom(mysql, ...)
}

dependencies {
  implementation "com.example:example:1.0.0"
  mysql "mysql:mysql-connector-java:8.0.16"

}

And then your custom build task

task buildMysql(type: com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar) {
    archiveName = "jdbc-mysql.${extension}"
    manifest {
        attributes('Main-Class': 'com.example.App')
    }
    exclude('META-INF/INDEX.LIST', 'META-INF/*.SF', 'META-INF/*.DSA', 'META-INF/*.RSA', 'module-info.class')

    configurations = [project.configurations.mysql]
    from project.convention.getPlugin(JavaPluginConvention).sourceSets.main.output
}