forked from pachyderm/pachyderm
/
retry.go
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/
retry.go
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package backoff
import "time"
// An Operation is executing by Retry() or RetryNotify().
// The operation will be retried using a backoff policy if it returns an error.
type Operation func() error
// Notify is a notify-on-error function. It receives an operation error and
// backoff delay if the operation failed (with an error).
//
// If the notify function returns an error itself, we stop retrying and return
// the error.
//
// NOTE that if the backoff policy stated to stop retrying,
// the notify function isn't called.
type Notify func(error, time.Duration) error
// Retry the operation o until it does not return error or BackOff stops.
// o is guaranteed to be run at least once.
// It is the caller's responsibility to reset b after Retry returns.
//
// Retry sleeps the goroutine for the duration returned by BackOff after a
// failed operation returns.
func Retry(o Operation, b BackOff) error { return RetryNotify(o, b, nil) }
// RetryNotify calls notify function with the error and wait duration
// for each failed attempt before sleep.
func RetryNotify(operation Operation, b BackOff, notify Notify) error {
var err error
var next time.Duration
b.Reset()
for {
if err = operation(); err == nil {
return nil
}
if next = b.NextBackOff(); next == Stop {
return err
}
if notify != nil {
if err := notify(err, next); err != nil {
return err
}
}
time.Sleep(next)
}
}