golang：内存问题

Question

我的记忆力有问题。我不明白为什么当我的程序运行很长时间时 Go 使用越来越多的内存（从不释放它）。

第一次分配后，程序使用了将近 9 MB 的内存。然后在 12 小时后，它开始以指数方式使用更多内存，直到 800 MB。

//.....code.....
if bol {
    // Assignment Struct.Var
    Struct_VastScript.TxtNoticeTop = JsonStruct_S.Options.TxtNoticeTop
    Struct_VastScript.TxtNoticeBottom = JsonStruct_S.Options.TxtNoticeBottom
    Struct_VastScript.Loop = JsonStruct_S.Options.Loop

    Struct_Image, err := getImage(Struct_VastScript.Video)
    if err == nil {
        if mobile == "true" {
            Struct_VastScript.Image = Struct_Image.URL360
        }
    }
    //open and parse a template file
    fi = path.Join("templates/VastPlayer", "TempVastPlayer.txt")
    tmpl, err := template.ParseFiles(fi)

    if err != nil {
        job_1.Complete(health.Panic)
        return false, err
    }
    //substitute fields in the template 'tmpl', with values from 'XmlStruct_V' and write it out to 'buf'
    var buf bytes.Buffer
    if err := tmpl.Execute(&buf, Struct_VastScript); err != nil {
        //if  err := tmpl.Execute(w, XmlStruct_V); err != nil {
        job_1.Complete(health.Panic)
        return false, err
    }

    // Call Func randString() : return alphanum random
    dir := randString(12)
    fpath := "http://creative2.xxx.io/api/html/" + dir

    // Create a new EndPoint to write the generated 'template' on 'w' http.ResponseWriter
    routeHtml := "/api/html/" + dir
    http.HandleFunc(routeHtml, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        //writes Template to 'w' http.ResponseWriter
        fmt.Fprintf(w, buf.String())
        fmt.Println("successfull Operation 2 !!")
        fmt.Println("")
        job_2.Complete(health.Success)
    }))


    //Call Func JsonReply(): return the finale Json response
    str := JsonReply(fpath, JsonStruct_S.Options.Animated, JsonStruct_S.Options.Responsive, JsonStruct_S.Options.Clickurl, JsonStruct_S.Options.Width, JsonStruct_S.Options.Height, adid, campaignid, JsonStruct_S.Type, JsonStruct_S.Options.Aspectratio, mobile)
    w.Header().Set("Content-Type", "application/json")
    //writes FinaleJson to 'w' http.ResponseWriter(it contains the link of the second endpoint "/api/html/")
    fmt.Fprint(w, str)
    fmt.Println("successfull Operation !!")
    fmt.Println("")
    job_1.Complete(health.Success)
    return true, nil
} else {
    return false, nil
}

对于每次调用，我的服务需要使用我收到的参数生成一个新模板，如您所见，我为每次调用创建了一个新端点，我不知道这是否是个好主意，我认为问题来自这部分代码，但我不确定，因为我不知道 GO 是如何管理它的。

Answer 1

显然，您不应该在每次出现请求时都创建处理程序。他们从不释放内存，所以你最终会遇到内存不足的异常。

相反，将处理程序端点放入数组（切片）并使用一个处理程序通过查看此切片中的 URL 来响应请求，然后从不需要的切片中删除项目更长。

所以基本上，而不是

routeHtml := "/api/html/" + dir
http.HandleFunc(routeHtml, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    //writes Template to 'w' http.ResponseWriter
    fmt.Fprintf(w, buf.String())
    fmt.Println("successfull Operation 2 !!")
    fmt.Println("")
    job_2.Complete(health.Success)
}))

做

type JobInfo struct {
    Path string
    // some data here
}

// maybe global context
var jobs []JobInfo

// initialisation
jobs = make([]JobInfo, 0)

http.HandleFunc("/api/html/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    path := r.URL.Path
    var job *JobInfo
    for _, j := range jobs {
        if j.Path == path {
            job = &j
            break
        }
    }

    if job != nil {
        // handle job request here
    }
}))

// and then in the jobs' loop
handlers = append(handlers, JobInfo{"/api/html/" + dir, ...})

它会起作用 because:

Patterns name fixed, rooted paths, like "/favicon.ico", or rooted subtrees, like "/images/" (note the trailing slash). Longer patterns take precedence over shorter ones, so that if there are handlers registered for both "/images/" and "/images/thumbnails/", the latter handler will be called for paths beginning "/images/thumbnails/" and the former will receive requests for any other paths in the "/images/" subtree.

当然不要忘记清理数组 jobs。

Answer 2

与其使用 slice 不如使用 map

type JobInfo struct {
    Path string
    // some data here
}

    // global context
    var jobs map[string]JobInfo

// initialisation
jobs = make(map[string]JobInfoStruct)


http.HandleFunc("/api/html/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    path := r.URL.Path
    var job JobInfoStruct
    var ok bool

    job, ok = jobs[path]
    if ok {
      // handle job request here
      //then after delete the job
      delete(jobs, path)
    }

}))

 // and then in the jobs' loop
pathVideo := "/api/html/" + dir
jobs[pathVideo] = JobInfoStruct{pathVideo, ...}

golang：内存问题

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