For TCP sockets, there's SetDeadline, SetReadDeadline and
SetWriteDeadline. See https://pkg.go.dev/net
For the originally posted code, I would replace
time.Sleep(5 * time.Second)
with code which either waits 5 seconds, or terminates on a shutdown signal
if that is received first. The idiomatic way to do that is with a context
<https://go.dev/blog/context>.
select {
case <-ctx.Done():
return // context cancelled
case <-time.After(5 * time.Second):
}
On Saturday, 16 April 2022 at 16:05:11 UTC+1 rog wrote:
> I'm not sure what you think such a general feature might look like.
>
> In general, it's not a good idea to force an arbitrary thing to stop,
> because that can leave resources in an undefined state, so the only
> reasonable approach AFAICS is to ask the function that's running to stop.
> That functionality is provided by the language with channels and by the
> standard library with the context package.
>
> On Sat, 16 Apr 2022, 15:25 Zhaoxun Yan, <yan.z...@gmail.com> wrote:
>
>> Thanks rog!
>>
>> I already dealt with it in my project since the Listen of gorilla
>> websocket did as you just mentioned - close and even throw out an error.
>> But I am surprised at why golang still has not provided a general feature
>> on that.
>>
>> Zhaoxun
>>
>> On Sat, Apr 16, 2022 at 10:14 PM roger peppe <rogp...@gmail.com> wrote:
>>
>>> Most network functions provide a way to provide a timeout or
>>> cancellation explicitly. Listen is one such: see this method - if the
>>> context that it's passed is cancelled, the Listen call will return.
>>> https://pkg.go.dev/net#ListenConfig.Listen
>>>
>>> The most general way to stop waiting on timeout or cancellation in the
>>> absence of explicitly provided functionality is to start the function in a
>>> separate goroutine and send notification when the function completes. This
>>> is non-ideal because the goroutine will remain around even when the waiter
>>> has given up, but can still be a useful technique in some circumstances.
>>>
>>> Hope this helps,
>>> rog.
>>>
>>> On Sat, 16 Apr 2022, 14:30 Zhaoxun Yan, <yan.z...@gmail.com> wrote:
>>>
>>>> Timeout is quite common practice in programming. For example, Listen
>>>> function in internet connection with a timeout may just close the
>>>> connection and Listen thread as silence persists for some period, like 60
>>>> seconds.
>>>>
>>>> I found it very hard to implement such a general shutdown feature of a
>>>> thread/goroutine on such I/O functions, here is one unsuccessful try,
>>>> which
>>>> I want to stop the whole in 9 seconds but it does not function as I wanted:
>>>>
>>>> package main
>>>>
>>>> import (
>>>> "fmt"
>>>> "time"
>>>> )
>>>>
>>>> func wait(){
>>>> time.Sleep(5 * time.Second)
>>>> fmt.Println("wait 1st signal")
>>>> time.Sleep(5 * time.Second)
>>>> fmt.Println("wait 2nd signal")
>>>> }
>>>>
>>>>
>>>> func main() {
>>>> ticker := time.NewTicker(3 * time.Second)
>>>> i := 0
>>>> for{
>>>> select{
>>>> case <- ticker.C:
>>>> i++
>>>> fmt.Printf("ticker rings %d\n", i)
>>>> if i==3{
>>>> return
>>>> }
>>>> default:
>>>> wait()
>>>> }
>>>> }
>>>>
>>>> }
>>>>
>>>> The result is to wait whole 30 seconds:
>>>> wait 1st signal
>>>> wait 2nd signal
>>>> ticker rings 1
>>>> wait 1st signal
>>>> wait 2nd signal
>>>> ticker rings 2
>>>> wait 1st signal
>>>> wait 2nd signal
>>>> ticker rings 3
>>>>
>>>> An online course suggests to wrap up the wait/Listen function with a
>>>> channel (which would return something instead of nothing above)
>>>>
>>>> go func(){
>>>> resultChan <- Listen()
>>>> }()
>>>>
>>>> select{
>>>> case a := <- resultChan:
>>>> //analyze a
>>>> case <-ticker.C:
>>>> //might break or return
>>>> }
>>>>
>>>> But this recipe obviously only kill the select goroutine rather than
>>>> the anonymous goroutine that actually runs Listen function. My question is
>>>> - how to kill the waiting or listening goroutine from outside?
>>>>
>>>> --
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>>>> https://groups.google.com/d/msgid/golang-nuts/e774c5a4-ed53-43da-a1fe-0d617603e223n%40googlegroups.com
>>>>
>>>> <https://groups.google.com/d/msgid/golang-nuts/e774c5a4-ed53-43da-a1fe-0d617603e223n%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>> .
>>>>
>>>
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