Fixed memory leaking

main.go

package main

import (
	"fmt"
	"io/ioutil"
	"net/http"
	"runtime"
	"time"

	"gocv.io/x/gocv"
)

type Pool struct {
	JobChan chan Job
}

func NewPool(maxRoutines, chanLen int) *Pool {
	p := new(Pool)
	p.JobChan = make(chan Job, chanLen)
	for i := 0; i < maxRoutines; i++ {
		go func() {
			runtime.LockOSThread()
			defer runtime.UnlockOSThread()
			for job := range p.JobChan {
				job.Process()
			}
		}()
	}

	return p
}

type Job interface {
	Process()
}

type ImageWork struct {
	ImageBytes []byte
}

func (i *ImageWork) Process() {
	DecodeAndClose(i.ImageBytes)
}

var jobQueue chan Job

func main() {
	pool := NewPool(runtime.GOMAXPROCS(0), 100)
	jobQueue = pool.JobChan

	fmt.Println("Started")
	http.HandleFunc("/file", FileHandler)
	http.ListenAndServe(":8080", nil)
}

func FileHandler(w http.ResponseWriter, r *http.Request) {
	fmt.Println(time.Now(), "FileHander")
	r.ParseMultipartForm(2 << 20)
	_, h, err := r.FormFile("file")
	if err != nil {
		fmt.Fprintln(w, err)
	}
	f, err := h.Open()
	i := &ImageWork{}
	i.ImageBytes, err = ioutil.ReadAll(f)
	if err != nil {
		fmt.Fprintln(w, err)
	}
	f.Close()
	jobQueue <- i
	fmt.Fprintln(w, "ok")
}

func DecodeAndClose(b []byte) {
	m, err := gocv.IMDecode(b, gocv.IMReadUnchanged)
	if err != nil {
		fmt.Println(err)
	}
	gocv.IMWrite("/img/test.jpg", m)
	m.Close()
}