Namespace confusion

borked.go

package main

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
	"runtime"

	"github.com/cloudfoundry-incubator/ducati-daemon/lib/namespace"
	"github.com/cloudfoundry-incubator/ducati-daemon/ossupport"
	"github.com/pivotal-golang/lager"
)

func main() {
	input := make(chan struct{})

	logger := lager.NewLogger("borked")
	threadLocker := &ossupport.OSLocker{}
	pathOpener := &namespace.PathOpener{
		Logger:       logger,
		ThreadLocker: threadLocker,
	}

	hostNamespace, err := pathOpener.OpenPath("/proc/self/ns/net")
	if err != nil {
		panic(err)
	}
	fmt.Printf("host namespace: %s\n", hostNamespace)

	tempDir, err := ioutil.TempDir("", "namespace")
	if err != nil {
		panic(err)
	}

	repo, err := namespace.NewRepository(logger, tempDir, threadLocker)
	if err != nil {
		panic(err)
	}

	testNamespace, err := repo.Create("test-namesapce")
	if err != nil {
		panic(err)
	}
	fmt.Printf("test namespace: %s\n", testNamespace)

	err = testNamespace.Execute(func(*os.File) error {
		for i := 0; i < 10; i++ {
			ready := make(chan struct{})
			go wait(input, ready)
			<-ready
		}
		return nil
	})
	if err != nil {
		panic(err)
	}

	dumpNamespaces()
	close(input)
}

func wait(input <-chan struct{}, ready chan struct{}) {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	close(ready)
	for {
		if _, ok := <-input; !ok {
			return
		}
	}
}

func dumpNamespaces() {
	findCommand := fmt.Sprintf(`find /proc/%d -type l -name net -exec ls -l {} \;`, os.Getpid())
	command := exec.Command("bash", "-c", findCommand)

	output, err := command.Output()
	fmt.Printf("%s\n", string(output))
	if err != nil {
		panic(err)
	}
}