// sleepWithInterrupt attempts to sleep for the specified duration, aborting
// early if the application is shutdown, returning true.
func (a *application) sleepWithInterrupt(ctx context.Context, amount time.Duration) bool {
select {
case <-clock.After(ctx, noMessageDelay):
return false
case <-a.shutdownC:
return true
}
}
// Retry executes a function. If the function returns an error, it will
// be re-executed according to a retry plan.
//
// If the supplied context is cancelled, retry will stop executing. Retry will
// not execute the supplied function at all if the context is canelled when
// Retry is invoked.
//
// If notify is not nil, it will be invoked if an error occurs (prior to
// sleeping).
func Retry(ctx context.Context, it Iterator, f func() error, callback Callback) (err error) {
for {
// If we've been cancelled, don't try/retry.
select {
case <-ctx.Done():
return ctx.Err()
default:
break
}
// Execute the function.
err = f()
if err == nil || it == nil {
return
}
delay := it.Next(ctx, err)
if delay == Stop {
return
}
// Notify our observer that we are retrying.
if callback != nil {
callback(err, delay)
}
if delay > 0 {
select {
case <-ctx.Done():
return ctx.Err()
case <-clock.After(ctx, delay):
break
}
}
}
}