goback

Goback implements a simple exponential backoff.

An exponential backoff approach is typically used when treating with potentially faulty/slow systems. If a system fails quick retries may exacerbate the system specially when the system is dealing with several clients. In this case a backoff provides the faulty system enough room to recover.

How to use

func main() {
        b := &goback.SimpleBackoff(
                Min:    100 * time.Millisecond,
                Max:    60 * time.Second,
                Factor: 2,
        )
        goback.Wait(b)           // sleeps 100ms
        goback.Wait(b)           // sleeps 200ms
        goback.Wait(b)           // sleeps 400ms
        fmt.Println(b.NextRun()) // prints 800ms
        b.Reset()                // resets the backoff
        goback.Wait(b)           // sleeps 100ms
}

Furter examples can be found in the examples folder.

Strategies

At the moment there are two backoff strategies implemented.

Simple Backoff

It starts with a minumum duration and multiplies it by the factor until the maximum waiting time is reached. In that case it will return Max.

The optional MaxAttempts will limit the maximum number of retries and will return an error when is exceeded.

Jitter Backoff

The Jitter strategy is based on the simple backoff but adds a light randomisation to minimise collisions between contending clients.

The result of the 'NextDuration()' method will be a random duration between [d-min, d+min] where d is the expected duration without jitter and min is the minimum duration.

Extensibility

By creating structs that implement the methods of the Backoff interface you will be able to use them as a backoff strategy.

A naive example of this is:

type NaiveBackoff struct{}

func (b *NaiveBackoff) NextAttempt() (time.Duration, error) { return time.Second, nil }
func (b *NaiveBackoff) Reset() { }

This will return always a 1s duration.

Credits

This package is inspired in https://github.com/jpillora/backoff

License

Distributed under MIT license. See LICENSE file for more information.