net.Listener Accept() timeout?

[al...@sneer.at]

Hiho,

I want to timeout and close a listening socket when no client connects within 5 seconds.

So im stuck with the following code:

conchan := make(chan bool)
stop := false
var conn net.Conn

go func() {
    select {
       case <-conchan:
         ...
         close(conchan)
          return
       case <-time.After(time.Second * 5):
         ...
         e := listener.Close()
         stop = true
          if e != nil {
         fmt.Printf("%v\n", e)
         }
      return
    }
 }()

// blocks
 conn, _ = listener.Accept()
conchan <- true

Now when someone connects within 5 seconds, a true is sent to conchan and that works fine.

But it doesnt matter if a client connects or not, after 5 seconds I land at the time.After case even when I previously ran into the conchan case and returned the function.

Is there a better/elegant way? Or what do I do wrong...

Any help highly appreciated.

[nkatsaros]

Use listener.SetDeadline(time.Now().Add(5*time.Second)) and then listener.Accept() will return an error if no connection is received after the deadline. You can assert the error to a *net.OpError (I think) using nErr, ok := err.(*net.OpError) and then check nErr.Timeout() to see if it was related to the deadline instead of a real error.

[Dave Cheney]

if err, ok := err.(*netOpError); ok && err.Timeout() {

   // it was a timeout

[Alexander Frimmel]

I saw that SetDeadline method before, but I made another mistake which was not shown in my posted code.

For the record:
I was using "listener net.Listener" as function parameter and "net.Listener" doesnt implement "SetDeadline". So I was struggling and just didn't recognize.

Switching to: "listener *net.TCPListener" and catching the timeout with your solution is working perfectly fine.

Thanks both of you!

[Dave Cheney]

if l, ok := l.(*net.TCPListner); ok {
// l _is_ a *net.TCPListener inside this block
l.SetTimeout(9000 * time.Second)

> --
> You received this message because you are subscribed to a topic in the
> Google Groups "golang-nuts" group.
> To unsubscribe from this topic, visit
> https://groups.google.com/d/topic/golang-nuts/kYI-xCyiZ0k/unsubscribe.
> To unsubscribe from this group and all its topics, send an email to
> golang-nuts...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.