awscallerid.scala

import scala.sys.process._

lazy val ecrCallerId = settingKey[String]("AWS caller ID")
ecrCallerId in ThisBuild := {
  val os   = new java.io.ByteArrayOutputStream
  ("aws sts get-caller-identity --output text" #> os).!
  os.close()
  val output = os.toString.trim

  output.takeWhile(_ != '\t')
}