hotrod/main.go

package main

import (
	"flag"
	"fmt"
	"os/exec"
	"runtime"
	"time"
)

func getTemp() (float64, error) {
	out, err := exec.Command("cat", "/sys/class/thermal/thermal_zone0/temp").Output()
	if err != nil {
		return 0, err
	}
	var tempMilli float64
	fmt.Sscanf(string(out), "%f", &tempMilli)
	return tempMilli / 1000, nil
}

func eatCPU(stop <-chan bool) {
	for {
		select {
		case <-stop:
			return
		default:
			_ = 1.0001 * 1.0001 // keep CPU busy
		}
	}
}

func main() {
	targetTemp := flag.Float64("t", 70, "Target temperature in Celsius")
	flag.Parse()

	fmt.Printf("Heating CPU to %.1f°C...\n", *targetTemp)

	stop := make(chan bool)
	go eatCPU(stop)

	for {
		temp, err := getTemp()
		if err != nil {
			fmt.Println("Error reading temperature:", err)
			break
		}

		fmt.Printf("Current temperature: %.1f°C\r", temp)
		if temp >= *targetTemp {
			fmt.Println("\nTarget reached. Cooling down...")
			stop <- true
			break
		}
		time.Sleep(500 * time.Millisecond)
	}

	runtime.GC()
}