In the link above, Search() will start a goroutine like

Question

In the link above, Search() will start a goroutine like

this:
res := make(chan []string)
go func() {
res <- slowSearch(from, to)
close(res)
}()
and in next step, it will wait for cahnnels in a select:
// wait for 2 events: either of one will be the result
for {
select {
case dst := <-res:
return dst, nil
case <-ctx.Done():
return []string{}, ctx.Err()
}
}

So when <-ctx.Done() going to have any message, it will return our function return []string{}, ctx.Err().

My question is: after canceling the context and return from Search, the main problem is our goroutine is still running in the background!
for example, the slowSearch() takes 17 seconds to write result into our res channel. and our context timeout is (for example) 3 seconds.
Now after Search() reaching the timeout, our context will be canceled, and Search() will be returned.
But slowSearch() still running in backgroun for 17 seconds!

What should we do in this case?

0

21.11.2020

7 ответов

11 просмотров

Roman Sharkov

there’s no way to kill a goroutine, so you must write slowSearch in such a way that it respects a cancalable context. slowSearch must check whether the context was canceled and return ASAP

0

22.11.2020

Daddy Автор вопроса

Roman Sharkov
there’s no way to kill a goroutine, so you must wr...

slowSearch() can do one thing at same time Either wait for context to be canceled, or doing its own job! My problem is here

0

22.11.2020

Roman Sharkov

Daddy
slowSearch() can do one thing at same time Either ...

what? I don’t understand

0

22.11.2020