How to add commit hash to Play templates?

Question

I want to put the commit hash into a Play Framework template file so that I can view the build information via REST GET call.

In sbt I can get a git commit hash and the git branch name, is there anyway to put this information into a template file during the build process?

build.sbt

name := "my-project"

val branch = "git rev-parse --abbrev-ref HEAD".!!.trim
val commit = "git rev-parse HEAD".!!.trim
val buildTime = (new java.text.SimpleDateFormat("yyyyMMdd-HHmmss")).format(new java.util.Date())

version := "%s-%s-%s".format(branch, commit, buildTime)

Answer 1

I used an sbt plugin called sbt-buildinfo to do this. See the answer to Does sbt have something like gradle's processResources task with ReplaceTokens support? . Technically, it worked. Effectively it kind-of sucked in that Play would reload the whole project every time anything changed. Perhaps they've overcome this by now? Give sbt-buildinfo a try: https://github.com/sbt/sbt-buildinfo#usage

Example usage:

lazy val root = (project in file("."))
  .enablePlugins(BuildInfoPlugin)
  .settings(
    buildInfoKeys := Seq[BuildInfoKey](
      <whateverYouWant>,
      BuildInfoKey.action("commit") {
        scala.sys.process.Process("git rev-parse HEAD").!!.trim
      }
    )
  )

Answer 2

Adding my ugly solution to add git head hash to build:
(addition to the links from Bob Kuhar's answer)
I've already had "lazy val root" so this is what it looks like right now.

lazy val root = (project in file(".")).
  enablePlugins(PlayScala).
  enablePlugins(BuildInfoPlugin).
  settings(
    buildInfoKeys := Seq[BuildInfoKey](
      name, version, scalaVersion, sbtVersion,
      "hostname" -> java.net.InetAddress.getLocalHost().getHostName(),
      "whoami" -> System.getProperty("user.name"),
      "buildTimestamp" -> new java.util.Date(System.currentTimeMillis()),      
      "gitHash" -> new java.lang.Object(){
              override def toString(): String = {
                      try { 
                    val extracted = new java.io.InputStreamReader(
                              java.lang.Runtime.getRuntime().exec("git rev-parse HEAD").getInputStream())                         
                    (new java.io.BufferedReader(extracted)).readLine()
                      } catch {      case t: Throwable => "get git hash failed"    }
              }}.toString()
    ),
    buildInfoPackage := "buildpkg"
  )