cpu_ctrl/consumer/speed_controller.go

package consumer

import (
	"fmt"
	"os/exec"
	"amuz.es/src/infra/cpu_ctrl/util"
	"time"
	"amuz.es/src/infra/cpu_ctrl/processor"
	"amuz.es/src/infra/cpu_ctrl/logger"
	"bytes"
)

var (
	fanspeedLogger = logger.NewLogger("fanspeed")
)

type fanControl struct {
	processorCount   int
	handler          util.Handler
	fanSpeedConsumer chan processor.FanspeedInfo
	sampleDuration   time.Duration
}

type FanControl interface {
	Consumer() chan<- processor.FanspeedInfo
	StartControl()
}

func NewFanControl(processorCount int, sampleDuration time.Duration, handler util.Handler) FanControl {
	return &fanControl{
		processorCount:   processorCount,
		handler:          handler,
		fanSpeedConsumer: make(chan processor.FanspeedInfo, processorCount),
		sampleDuration:   sampleDuration,
	}
}

func (c *fanControl) Consumer() chan<- processor.FanspeedInfo { return c.fanSpeedConsumer }

func (c *fanControl) StartControl() {
	defer c.handler.DecreaseWait()
	defer func() {
		if err := recover(); err != nil {
			c.handler.NotifyError(err.(error))
		}
	}()
	defer close(c.fanSpeedConsumer)
	defer fanspeedLogger.Info("Fan control stopped")
	fanspeedLogger.Info("Fan control started")

	ticker := time.Tick(c.sampleDuration)
	pastFanSpeedList, newFanSpeedList := make([]int, c.processorCount), make([]int, c.processorCount)
	for {
		select {
		case <-ticker:
			go c.applyFanspeed(pastFanSpeedList, newFanSpeedList)
			pastFanSpeedList, newFanSpeedList = newFanSpeedList, make([]int, c.processorCount)
			copy(newFanSpeedList, pastFanSpeedList)
		case changedSpeed := <-c.fanSpeedConsumer:
			newFanSpeedList[changedSpeed.Id] = changedSpeed.FanSpeed
		case <-c.handler.Done():
			return
		}
	}
}
func (c *fanControl) applyFanspeed(pastFanSpeedList, newFanSpeedList []int) {
	if !compareFanSpeed(pastFanSpeedList, newFanSpeedList) {
		return
	}

	args := make([]string, 0)
	args = append(args, "raw", "0x3a", "0x01", )
	for _, item := range newFanSpeedList {
		args = append(args, fmt.Sprintf("0x%x", item))
	}
	args = append(args,
		"0x0", "0x0", "0x0", "0x0", "0x0", "0x0",
	)
	cmd := exec.Command("ipmitool", args...)
	if err := cmd.Run(); err != nil {
		c.handler.NotifyError(err)
		return
	}
	buf := bytes.NewBufferString("")
	for _, item := range newFanSpeedList {
		buf.WriteString(fmt.Sprintf("0x%x", item))
		buf.WriteRune(' ')
	}
	fanspeedLogger.Infof("Commit fan speed with %s", buf.String())
}

func compareFanSpeed(old, new []int) bool {
	new = new[:len(old)] // this line is the key
	for i, v := range old {
		if v != new[i] { // here is no bounds checking for b[i]
			return false
		}
	}
	return true
}