netns/README.md

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# netns - network namespaces in go #
The netns package provides an ultra-simple interface for handling
network namespaces in go. Changing namespaces requires elevated
privileges, so in most cases this code needs to be run as root.
## Local Build and Test ##
You can use go get command:
go get github.com/vishvananda/netns
Testing (requires root):
sudo -E go test github.com/vishvananda/netns
## Example ##
```go
package main
import (
"fmt"
"net"
"runtime"
"github.com/vishvananda/netns"
)
func main() {
// Lock the OS Thread so we don't accidentally switch namespaces
runtime.LockOSThread()
defer runtime.UnlockOSThread()
// Save the current network namespace
origns, _ := netns.Get()
defer origns.Close()
// Create a new network namespace
newns, _ := netns.New()
defer newns.Close()
// Do something with the network namespace
ifaces, _ := net.Interfaces()
fmt.Printf("Interfaces: %v\n", ifaces)
// Switch back to the original namespace
netns.Set(origns)
}
```
## NOTE
The library can be safely used only with Go >= 1.10 due to [golang/go#20676](https://github.com/golang/go/issues/20676).
After locking a goroutine to its current OS thread with `runtime.LockOSThread()`
and changing its network namespace, any new subsequent goroutine won't be
scheduled on that thread while it's locked. Therefore, the new goroutine
will run in a different namespace leading to unexpected results.
See [here](https://www.weave.works/blog/linux-namespaces-golang-followup) for more details.