Scalaで/proc/statのCPU情報を解析するだけの簡単な

ProcStat.scala

package utils

import java.nio.charset.StandardCharsets
import java.nio.file.{Files, Paths}

import scala.collection.JavaConverters._

object ProcStat {
  val StatPath = Paths.get("/proc/stat")
  def cpuStats: CpuStats = {
    val lines = Files.readAllLines(StatPath, StandardCharsets.US_ASCII).asScala
    val all = CpuStat.fromLine(lines.head)
    val cores = lines.tail.flatMap { line =>
      if(line.startsWith("cpu")) {
        Some(CpuStat.fromLine(line))
      } else None
    }
    CpuStats(all, cores)
  }
}

case class CpuStats(all: CpuStat, cores: Seq[CpuStat])

case class CpuStat(user: Long, nice: Long, system: Long, idle: Long) {
  def usage: Double = (user + nice + system) / (user + nice + system + idle)
}

object CpuStat {
  val Spaces = """\s+""".r
  def fromLine(line: String) = {
    val Array(_, user, nice, system, idle) = Spaces.split(line).take(5)
    CpuStat(user.toLong, nice.toLong, system.toLong, idle.toLong)
  }
}