我有一个 Go1.5.1 进程/应用程序。当我在该进程上运行 /usr/sbin/lsof -p 时，我看到很多“无法识别协议(protocol)”。

monitor_ 13105 root  101u  sock      0,6      0t0 16960100 can't identify protocol
monitor_ 13105 root  102u  sock      0,6      0t0 21552427 can't identify protocol
monitor_ 13105 root  103u  sock      0,6      0t0 17565091 can't identify protocol
monitor_ 13105 root  104u  sock      0,6      0t0 18476870 can't identify protocol

进程状态/限制/fd

[root@Monitor_q ~]# cat /proc/13105/status 
Name:   monitor_client
State:  S (sleeping)
Tgid:   13105
Pid:    13105
PPid:   13104
TracerPid:  0
Uid:    0   0   0   0
Gid:    0   0   0   0
Utrace: 0
FDSize: 16384
Groups: 
...


[root@Monitor_q ~]# cat /proc/13105/limits 
Limit                     Soft Limit           Hard Limit           Units     
Max cpu time              unlimited            unlimited            seconds   
Max file size             unlimited            unlimited            bytes     
Max data size             unlimited            unlimited            bytes     
Max stack size            10485760             unlimited            bytes     
Max core file size        0                    unlimited            bytes     
Max resident set          unlimited            unlimited            bytes     
Max processes             3870                 3870                 processes 
Max open files            9999                 9999                 files     
Max locked memory         65536                65536                bytes     
Max address space         unlimited            unlimited            bytes     
Max file locks            unlimited            unlimited            locks     
Max pending signals       3870                 3870                 signals   
Max msgqueue size         819200               819200               bytes     
Max nice priority         0                    0                    
Max realtime priority     0                    0                    
Max realtime timeout      unlimited            unlimited            us

[root@Monitor_q ~]# ll /proc/13105/fd/
lrwx------ 1 root root 64 Dec  7 00:15 8382 -> socket:[52023221]
lrwx------ 1 root root 64 Dec  7 00:15 8383 -> socket:[51186627]
lrwx------ 1 root root 64 Dec  7 00:15 8384 -> socket:[51864232]
lrwx------ 1 root root 64 Dec  7 00:15 8385 -> socket:[52435453]
lrwx------ 1 root root 64 Dec  7 00:15 8386 -> socket:[51596071]
lrwx------ 1 root root 64 Dec  7 00:15 8387 -> socket:[52767667]
lrwx------ 1 root root 64 Dec  7 00:15 8388 -> socket:[52090632]
lrwx------ 1 root root 64 Dec  7 00:15 8389 -> socket:[51739068]
lrwx------ 1 root root 64 Dec  7 00:15 839 -> socket:[22963529]
lrwx------ 1 root root 64 Dec  7 00:15 8390 -> socket:[52023223]
lrwx------ 1 root root 64 Dec  7 00:15 8391 -> socket:[52560389]
lrwx------ 1 root root 64 Dec  7 00:15 8392 -> socket:[52402565]
...

但是netstat -a中没有类似的输出。

这些套接字是什么？我怎样才能知道它们的作用？

monitor_client.go

package main

import (
    "crypto/tls"
    "encoding/json"
    "fmt"
    "log"
    "net"
    "net/http"
    nurl "net/url"
    "strconv"
    "strings"
    "syscall"
    "time"
)

type Result struct {
    Error      string        `json:"error"`
    HttpStatus int           `json:"http_status"`
    Stime      time.Duration `json:"http_time"`
}

//http://stackoverflow.com/questions/20990332/golang-http-timeout-and-goroutines-accumulation
//http://3.3.3.3/http?host=3.2.4.2&servername=a.test&path=/&port=33&timeout=5&scheme=http
func MonitorHttp(w http.ResponseWriter, r *http.Request) {
    var host, servername, path, port, scheme string
    var timeout int
    u, err := nurl.Parse(r.RequestURI)
    if err != nil {
        log.Fatal(err)
        return
    }
    if host = u.Query().Get("host"); host == "" {
        host = "127.0.0.0"
    }
    if servername = u.Query().Get("servername"); servername == "" {
        servername = "localhost"
    }
    if path = u.Query().Get("path"); path == "" {
        path = "/"
    }
    if port = u.Query().Get("port"); port == "" {
        port = "80"
    }
    if scheme = u.Query().Get("scheme"); scheme == "" {
        scheme = "http"
    }

    if timeout, _ = strconv.Atoi(u.Query().Get("timeout")); timeout == 0 {
        timeout = 5
    }

    //log.Printf("(host)=%s (servername)=%s (path)=%s (port)=%s (timeout)=%d", host, servername, path, port, timeout)

    w.Header().Set("Content-Type", "application/json")

    res := httptool(host, port, servername, scheme, path, timeout)
    result, _ := json.Marshal(res)
    fmt.Fprintf(w, "%s", result)
}

func httptool(ip, port, servername, scheme, path string, timeout int) Result {

    var result Result
    startTime := time.Now()
    host := ip + ":" + port

    transport := &http.Transport{
        TLSClientConfig:   &tls.Config{InsecureSkipVerify: true},
        DisableKeepAlives: true,
    }

    dialer := net.Dialer{
        Timeout:   time.Duration(timeout) * time.Second,
        KeepAlive: 0 * time.Second,
    }
    transport.Dial = func(network, address string) (net.Conn, error) {
        return dialer.Dial(network, address)
    }

    client := &http.Client{
        Transport: transport,
    }
    rawquery := ""
    url := fmt.Sprintf("%s://%s%s%s", scheme, host, path, rawquery)
    req, err := http.NewRequest("GET", url, nil)
    if err != nil {
        result.HttpStatus = -1
        errs := strings.Split(err.Error(), ": ")
        result.Error = errs[len(errs)-1]
        result.Stime = time.Now().Sub(startTime) / time.Millisecond
        return result
    }
    req.Header.Set("User-Agent", "monitor worker")
    req.Header.Set("Connection", "close")
    req.Host = servername
    resp, err := client.Do(req)
    //https://github.com/Basiclytics/neverdown/blob/master/check.go
    if err != nil {
        nerr, ok := err.(*nurl.Error)
        if ok {
            switch cerr := nerr.Err.(type) {
            case *net.OpError:
                switch cerr.Err.(type) {
                case *net.DNSError:
                    errs := strings.Split(cerr.Error(), ": ")
                    result.Error = "dns: " + errs[len(errs)-1]
                default:
                    errs := strings.Split(cerr.Error(), ": ")
                    result.Error = "server: " + errs[len(errs)-1]
                }
            default:
                switch nerr.Err.Error() {
                case "net/http: request canceled while waiting for connection":
                    errs := strings.Split(cerr.Error(), ": ")
                    result.Error = "timeout: " + errs[len(errs)-1]

                default:
                    errs := strings.Split(cerr.Error(), ": ")
                    result.Error = "unknown: " + errs[len(errs)-1]
                }
            }

        } else {
            result.Error = "unknown: " + err.Error()
        }
        result.HttpStatus = -2
        result.Stime = time.Now().Sub(startTime) / time.Millisecond
        return result
    }
    resp.Body.Close()
    result.HttpStatus = resp.StatusCode
    result.Error = "noerror"
    result.Stime = time.Now().Sub(startTime) / time.Millisecond //spend time (ms)
    return result
}

func setRlimit() {
    var rLimit syscall.Rlimit
    err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rLimit)
    if err != nil {
        log.Printf("Unable to obtain rLimit", err)
    }
    if rLimit.Cur < rLimit.Max {
        rLimit.Max = 9999
        rLimit.Cur = 9999
        err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rLimit)
        if err != nil {
            log.Printf("Unable to increase number of open files limit", err)
        }
    }
}

func main() {
    setRlimit()
    s := &http.Server{
        Addr:         ":59059",
        ReadTimeout:  7 * time.Second,
        WriteTimeout: 7 * time.Second,
    }
    http.HandleFunc("/http", MonitorHttp)

    log.Fatal(s.ListenAndServe())
}

最佳答案

这里有几点。

无论如何，我无法重现您的行为，can't identify protocol 通常与未正确关闭的套接字相关。

一些评论者建议您不必在每个处理程序中创建 http 客户端 - 这是真的。只需创建一次即可重复使用。

其次，我不确定您为什么要创建自己的 http.Client 结构以及为什么要禁用 keepalive。你不能只用 http.Get 吗？更简单的代码更容易调试。

第三，不知道为什么要覆盖 transport.Dial 函数。即使您必须这样做，文档(针对 Go 1.9.2)也说:

% go doc http.transport.dial
type Transport struct {
    // Dial specifies the dial function for creating unencrypted TCP
    connections.
    //
    // Deprecated: Use DialContext instead, which allows the transport
    // to cancel dials as soon as they are no longer needed.
    // If both are set, DialContext takes priority.
    Dial func(network, addr string) (net.Conn, error)

关于弃用和缺乏拨号重用的评论可能指向您问题的根源。

总而言之，在您的情况下，我会做两件事: * 将客户端创建移至执行一次的代码，或仅使用带有 http.Get 的默认客户端 * 我会通过覆盖默认传输字段来清理这个东西，如果你必须这样做，那么我会按照建议使用 DialContext。

祝你好运。

关于sockets - 套接字无法识别协议(protocol)(套接字泄漏)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34119757/