retry

Documentation

Index

• Variables
• func OnError(backoff wait.Backoff, retriable func(error) bool, fn func() error) error
• func RetryOnConflict(backoff wait.Backoff, fn func() error) error

Variables

var DefaultBackoff = wait.Backoff{
	Steps:    4,
	Duration: 10 * time.Millisecond,
	Factor:   5.0,
	Jitter:   0.1,
}

DefaultBackoff is the recommended backoff for a conflict where a client may be attempting to make an unrelated modification to a resource under active management by one or more controllers.

var DefaultRetry = wait.Backoff{
	Steps:    5,
	Duration: 10 * time.Millisecond,
	Factor:   1.0,
	Jitter:   0.1,
}

DefaultRetry is the recommended retry for a conflict where multiple clients are making changes to the same resource.

Functions

func OnError

func OnError(backoff wait.Backoff, retriable func(error) bool, fn func() error) error

OnError allows the caller to retry fn in case the error returned by fn is retriable according to the provided function. backoff defines the maximum retries and the wait interval between two retries.

func RetryOnConflict

func RetryOnConflict(backoff wait.Backoff, fn func() error) error

RetryOnConflict is used to make an update to a resource when you have to worry about conflicts caused by other code making unrelated updates to the resource at the same time. fn should fetch the resource to be modified, make appropriate changes to it, try to update it, and return (unmodified) the error from the update function. On a successful update, RetryOnConflict will return nil. If the update function returns a "Conflict" error, RetryOnConflict will wait some amount of time as described by backoff, and then try again. On a non-"Conflict" error, or if it retries too many times and gives up, RetryOnConflict will return an error to the caller.

err := retry.RetryOnConflict(retry.DefaultRetry, func() error {
    // Fetch the resource here; you need to refetch it on every try, since
    // if you got a conflict on the last update attempt then you need to get
    // the current version before making your own changes.
    pod, err := c.Pods("mynamespace").Get(name, metav1.GetOptions{})
    if err ! nil {
        return err
    }

    // Make whatever updates to the resource are needed
    pod.Status.Phase = v1.PodFailed

    // Try to update
    _, err = c.Pods("mynamespace").UpdateStatus(pod)
    // You have to return err itself here (not wrapped inside another error)
    // so that RetryOnConflict can identify it correctly.
    return err
})
if err != nil {
    // May be conflict if max retries were hit, or may be something unrelated
    // like permissions or a network error
    return err
}
...

TODO: Make Backoff an interface?