On Wed, Apr 12, 2023 at 7:29 AM Frank <francisbfwb...@gmail.com> wrote:
> Hi Gophers,
>
> So I've run into a situation where my code would run for a rather long
> time (10minutes - ~1 hour). And I want to cancel it halfway sometimes. I
> know I can use channel/context can check for channel message to return
> early. But this requires explicitly checking for channel status and would
> introduce many messy code blocks. Is it feasible (and good) for me to
> listen to some signal and use panic to stop the execution once signal
> received?
>
There are ways to reduce the boilerplate code. For instance:
func LongTask(ctx context.Context) {
canceled:=func() bool {
select {
case <-ctx.Done(): return true
default:
}
return false
}
...
if canceled() {
return
}
}
Or, if this involves lots of nesting, you can define:
canceled:=func() {
select {
case <-ctx.Done(): panic(errCanceled)
default:
}
}
so every now and then you can simply call canceled(). If you do this
though, you need to recover:
go func() {
defer func() {
if r:=recover(); r!=nil {
if errors.Is(r,errCanceled) {
// canceled
} else {
panic(r)
}
}
}()
LongTask(ctx)
}()
There is no way you can immediately stop a goroutine. Handling of a signal
has to happen in a separate goroutine, and you would still need to check
periodically in the actual goroutine you want to cancel.
> Thanks!
> Frank
>
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