Scala - Obtain FQDN

fqdn.scala

  def fqdn: Option[String] = {
    val marker = "domain "
    def ipv4(canonical: String): Boolean = {
      def isAllDigits(x: String) = x forall Character.isDigit
      canonical != null && !canonical.isEmpty && {
        val parts = canonical.split('.')
        parts.length > 1 && !parts.map(part => isAllDigits(part)).reduce(_ & _)
      }
    }
    val addr: java.net.InetAddress = java.net.InetAddress.getLocalHost
    val hostname: String = addr.getHostName
    val canonical: String = addr.getCanonicalHostName
    if(ipv4(canonical)) Some(canonical)
    else {
      val is: java.io.InputStream = new java.io.FileInputStream(new java.io.File("/etc/resolv.conf"))
      val lines = scala.io.Source.fromInputStream(is).getLines.toStream
      val domains: Seq[String] = lines.filter(line => line.startsWith(marker)).map(line => line.substring(marker.length).trim)
      if(domains.size == 0) None
      else {
        val domain = domains(0)
        Some(s"${hostname}.${domain}")
      }
    }
  }