void apply(Project project) {
        project.getTasks().register("hello", GreetingTask) {
            greeter.convention("Greeter")
        }
    }
}
// end::convention-callsites-from-plugin[]

apply plugin: GreetingPlugin

// tag::convention-callsites-from-buildscript[]
tasks.withType(GreetingTask).configureEach {
    // setting convention from build script
    guest.convention("Guest")
}

    override fun apply(project: Project) {
        project.getTasks().register<GreetingTask>("hello") {
            greeter.convention("Greeter")
        }
    }
}
// end::convention-callsites-from-plugin[]

// tag::convention-callsites-from-buildscript[]
apply<GreetingPlugin>()

tasks.withType<GreetingTask>().configureEach {
    // setting convention from build script
    guest.convention("Guest")
}

Using an extension and mapping it to a custom task's input/output properties is common in plugins.

In this example, the message property of the `GreetingPluginExtension` is mapped to the message property of the `GreetingTask` as an input:

====
include::sample[dir="snippets/plugins/greeting/kotlin", files="buildSrc/src/main/kotlin/greetings.gradle.kts[tags=task]"]