scala - SBT including the version number in a program

Question

I want a program I'm building to be able to report its own version at runtime (e.g. scala myprog.jar --version). Traditionally in a maven project, I'd use resource filtering (pom.xml -> file.properties -> read value at runtime). I know there's sbt-filter-plugin to emulate this functionality, but I'm curious if there's a more standard / preferred / clever way of doing this in SBT.

tl;dr how can I read the version number defined in build.sbt at runtime?

Answer 1

Update...

https://github.com/ritschwumm/xsbt-reflect (mentioned above) is Obsolete, but there is this cool SBT release tool that can automatically manage versions and more: https://github.com/sbt/sbt-release.

Alternatively, if you want a quick fix you can get version from manifest like this:

val version: String = getClass.getPackage.getImplementationVersion

This value will be equal to version setting in your project which you set either in build.sbt or Build.scala.

Another Update ...

Buildinfo SBT plugin can generate a class with version number based on build.sbt:

/** This object was generated by sbt-buildinfo. */
case object BuildInfo {
  /** The value is "helloworld". */
  val name: String = "helloworld"
  /** The value is "0.1-SNAPSHOT". */
  val version: String = "0.1-SNAPSHOT"
  /** The value is "2.10.3". */
  val scalaVersion: String = "2.10.3"
  /** The value is "0.13.2". */
  val sbtVersion: String = "0.13.2"
  override val toString: String = "name: %s, version: %s, scalaVersion: %s, sbtVersion: %s" format (name, version, scalaVersion, sbtVersion)
}

See the docs on how to enable it here: https://github.com/sbt/sbt-buildinfo/.