I want to know if there are any guarantees regarding the return order upon Context cancellation in golang.
I want to create a context with cancellation and once all the listeners are done with processing catching and reacting to "<-ctx.Done()" from this context, I want to call os.Exit safely.
A concrete example to explain the idea of what I want is following. I want to catch a signal, trigger all cancellations, and then call os.Exit().
I create a context and listen for a signal:
ctx, cancel := context.WithCancel(context.Background())
go func() {
c := make(chan os.Signal)
signal.Notify(c, os.Interrupt)
defer signal.Stop(c)
select {
case <-c:
cancel()
}
}()
In other places I "sign up" for this request several times:
res := NewRes()
go func() {
<-ctx.Done():
res.Close()
}()
But then I want to call os.Exit at the point when all the listeners are done.
For that I plan to create either parent or child context like this:
parent, pCancel := context.WithCancel(context.Background())
child, _ := context.WithCancel(parent)
go func() {
c := make(chan os.Signal)
signal.Notify(c, os.Interrupt)
defer signal.Stop(c)
select {
case <-c:
pCancel()
case <-child.Done():
os.Exit(0)
}
}()
Unfortunately, I did not find the documentation describing the order how context are canceled, so I cannot come up with the correct solution for now.