How to create a task in SBT that calls a method? - scala

Question

I am new developing tasks in SBT and I'm trying to figure out how to create a task that integrate my existing code.
In my code I have a singleton object that has run method that requires several parameters
object MyObject {
def run( param1: String, param2: Int, param3: String, ...) = {}
}
My question is: How can I define a Task in SBT that calls my run method specifying all its parameters in my build.sbt file?
I can imagine something like this in build.sbt
lazy val myTask: TaskKey[Seq[File]] = taskKey[Seq[File]]("My task")
lazy val myTaskRun = (sourceManaged, dependencyClasspath in Compile, runner in Compile, streams) map { (dir, cp, r, s) =>
val param1 = ...
val param2 = ...
val param3 = ...
val paramN = ....
MyObject.run( param1, param2, param3, ...)
Seq(file("path"))
}

Answer 1

1. You can use fullRunInputTask for that.
In your build.sbt
lazy val example = InputKey[Unit]("example", "Run something.")
fullRunInputTask( example, Compile, "somefun.CallMe")
Under src/main/scala/somefun/CallMe.scala
package somefun
object CallMe {
def main(args: Array[String]) : Unit = {
println("Params are: " + args.mkString(", "))
}
}
To call your task use example, e.g. "example 1 2 3"
2. You can create your own InputTask
see InputTask in SBT Doc
Creating a custom InputTask allows a flexible input parser (with suggestions on tab), allows linking with other tasks. It simple integrates better into SBT.