blob: 7e8a7c1083a5c0ff4975e7e8c9f603765113f858 [file] [log] [blame]
// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"fmt"
"log"
"os"
"strconv"
"strings"
"time"
)
const idleMaxLoad = 0.2
// loadAvg returns the 1-minute load average.
func loadAvg() (float64, error) {
b, err := os.ReadFile("/proc/loadavg")
if err != nil {
return 0, fmt.Errorf("error reading /proc/loadavg: %w", err)
}
s := strings.TrimSpace(string(b))
log.Printf("Load average: %s", s)
parts := strings.Split(s, " ")
avg, err := strconv.ParseFloat(parts[0], 64)
if err != nil {
return 0, fmt.Errorf("malformed load average %q: %v", parts[0], err)
}
return avg, nil
}
func waitForIdle() error {
avg, err := loadAvg()
if err != nil {
return fmt.Errorf("error reading load average: %w", err)
}
if avg < idleMaxLoad {
return nil
}
log.Printf("Waiting for load average to drop below %.2f...", idleMaxLoad)
tick := time.NewTicker(30 * time.Second)
defer tick.Stop()
for _ = range tick.C {
avg, err := loadAvg()
if err != nil {
return fmt.Errorf("error reading load average: %w", err)
}
if avg < idleMaxLoad {
break
}
log.Printf("Waiting for load average to drop below %.2f...", idleMaxLoad)
}
return nil
}