Gradle: how to get git hash in build.gradle

build.gradle

String getGitHash() {
    // git hash
    def command = Runtime.getRuntime().exec("git rev-parse --short HEAD")
    def result = command.waitFor()
    if (result != 0) {
        throw new IOException("Command 'getGitHash()' exited with " + result)
    }

    String gitCommitHash = command.inputStream.text.trim()

    //println("getGitHash() : " + gitCommitHash)

    return gitCommitHash
}