ImageNamePlugin.scala

import cloudflow.sbt.CloudflowKeys.{cloudflowDockerImageName, cloudflowDockerRegistry, cloudflowDockerRepository}
import cloudflow.sbt.ImagePlugin
import sbt.{AutoPlugin, Def, taskKey}

trait Key {
  val cloudflowImageName  = taskKey[String]("The name of the Docker image to publish.")
}

object ImageNamePlugin extends AutoPlugin {
  override def requires = ImagePlugin
  override def trigger           = allRequirements
  object autoImport extends Key
  import autoImport._

  override def projectSettings = Seq(
    cloudflowImageName := Def.taskDyn{
      Def.task{
        val maybeImage = for {
          img  <- cloudflowDockerImageName.value
          registry  <- cloudflowDockerRegistry.value
          namespace <- cloudflowDockerRepository.value
        } yield {
          s"$registry/$namespace/${img.name}:${img.tag}"
        }
        maybeImage.getOrElse("")
      }
    }.value
  )
}