Example packaging aggregation build definition.

build.sbt

addCommandAlias("package", "collectPackages")

addCommandAlias("stage", "universal:stage")

enablePlugins(GitBranchPrompt)

enablePlugins(JavaAppPackaging)

// TODO: Need to figure out how to look this up from the outer project
version in ThisBuild := "0.2.1-SNAPSHOT"

scalaVersion in ThisBuild := "2.11.6"

val baseSettings = Seq(
  classpathTypes += "war",
  publishArtifact in (Compile, packageDoc) := false,
  publishArtifact in packageDoc := false,
  sources in (Compile,doc) := Seq.empty
  )

sources in (Compile,doc) := Seq.empty

publishArtifact in (Compile, packageDoc) := false

// Due to the way that SBT works, subprojects have to be defined manually as below.
// IOW, don't try to refactor :-)
lazy val packaging = project
  .in(file("."))
  .aggregate(a, b)

lazy val runr = ProjectRef(file(".."), "runr")

lazy val a = Project(id = "runr-cli", base = file("runr-cli"))
  .dependsOn(runr)
  .settings(baseSettings: _*)

lazy val b = Project(id = "runr-gui", base = file("runr-gui"))
  .dependsOn(runr)
  .settings(baseSettings: _*)

val packageSubs = taskKey[Seq[File]]("Build packages in subrojects")
(packageSubs in packaging) := Seq(
  (packageBin.in(a, Universal)).value,
  (packageBin.in(b, JDKPackager)).value
)

// Collect all the generated packages in one place.
val collectPackages = taskKey[File]("Move built packages")
collectPackages := {
  val dest = target.value / "packages"
  dest.mkdirs()
  val files = packageSubs.value
  val dests = files.map { f ⇒
    val d = dest / f.getName
    IO.copyFile(f, d)
    d
  }
  streams.value.log.info(s"Collected packages in $dest:\n${dests.map(_.getName).mkString("  ","\n  ", "")}")
  dest
}