reproduce-docker-netns-bug.go

// Must start docker daemon with -H tcp://127.0.0.1:2375 
package main

import (
	"fmt"
	"io"
	"net/http"
	"os"
	"os/exec"
	"strings"
	"sync"
	"time"
)

type nopWriter struct{}

func (nopWriter) Write(p []byte) (n int, err error) { return len(p), nil }

func main() {
	var wg sync.WaitGroup
	for i := 0; i < 10; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			// If the "-i" is not specified or comment out the stats API call the problem won't reproduce.
			for {
				id := Exec("run", "-i", "-t", "-d", "busybox", "sh", "-c", "sleep 2")
				req, _ := http.NewRequest("GET", "http://127.0.0.1:2375/containers/"+id+"/stats", nil)
				resp, err := http.DefaultClient.Do(req)
				if err != nil {
					fmt.Println(err, resp)
					break
				}
				go io.Copy(nopWriter{}, resp.Body)
				time.Sleep(2500 * time.Millisecond)
				resp.Body.Close()
				Exec("rm", "-f", id)
			}
		}()
	}

	wg.Wait()
}

func Exec(args ...string) string {
	out, err := exec.Command("docker", args...).CombinedOutput()
	if err != nil {
		fmt.Println(err)
		fmt.Println(string(out))
		os.Exit(1)
	}
	return strings.TrimSpace(string(out))
}