build_info.sbt

lazy val generateBuildConfig = taskKey[Seq[File]]("Generates `build.conf`.")

generateBuildConfig := {
  val dest = (resourceManaged in Compile).value / "build.conf"
  val hash = Process("git rev-parse HEAD").!!.trim()
  val time = java.time.Instant.now()
  streams.value.log.info(s"Generating a build.conf: $dest")
  IO.write(dest,
    s"""build.info {
       |  hash: "$hash"
       |  time: "$time"
       |}
     """.stripMargin)
  Seq(dest)
}

resourceGenerators in Compile += generateBuildConfig.taskValue

resourceGenerators in Runtime += generateBuildConfig.taskValue

resourceGenerators in (Runtime, dist) += generateBuildConfig.taskValue