build.gradle

apply plugin: 'java'
sourceCompatibility = 1.8
project.version = 0.10
defaultTasks 'clean', 'build'

configurations {
    //declare custom pluginLibs configuration to include only libs for this plugin
    pluginLibs

    //declare compile to extend from pluginLibs so it inherits the dependencies
    compile {
        extendsFrom pluginLibs
    }
}

repositories {
    mavenCentral()
}

dependencies {
    pluginLibs group: 'org.freemarker', name: 'freemarker', version: '2.3.20'
    compile group: 'org.rundeck', name: 'rundeck-core', version: '3.0.11-20181221'
    compile group: 'org.slf4j', name: 'slf4j-api', version: '1.7.5'
}

// task to copy plugin libs to output/lib dir
task copyToLib(type: Copy) {
    into "$buildDir/output/lib"
    from configurations.pluginLibs
}

jar {
    //include contents of output dir
    from "$buildDir/output"
    manifest {
        attributes 'Rundeck-Plugin-Version': '1.1', 'Rundeck-Plugin-Archive': 'true', 'Rundeck-Plugin-File-Version': "${project.version}"
        //create space-separated list of pluginLibs
        def libList = configurations.pluginLibs.collect { 'lib/' + it.name }.join(' ')
        attributes 'Rundeck-Plugin-Classnames': 'com.bitplaces.rundeck.plugins.slack.SlackNotificationPlugin', 'Rundeck-Plugin-Libs': "${libList}"
    }
}

//set jar task to depend on copyToLib
jar.dependsOn(copyToLib)

task wrapper(type: Wrapper) {
    gradleVersion = '4.10.2'
}