waitext

Documentation

Overview

Package waitext implements behavior similar to https://github.com/cenkalti/backoff on top of k8s.io/apimachinery/pkg/util/wait.

Index

• Constants
• func DefaultExponentialBackoff() wait.Backoff
• func NewConstantBackoff(interval time.Duration) wait.Backoff
• func Retry(ctx context.Context, backoff wait.Backoff, retries int, ...) error

Constants

const (

	// Forever should be used to simulate infinite retries or backoff increase.
	// Usually it's wise to have a context with timeout to avoid an infinite loop.
	Forever = math.MaxInt32
)

Functions

func DefaultExponentialBackoff

func DefaultExponentialBackoff() wait.Backoff

DefaultExponentialBackoff creates an exponential backoff with sensible default values. Defaults should match ExponentialBackoff in github.com/cenkalti/backoff.

func NewConstantBackoff

func NewConstantBackoff(interval time.Duration) wait.Backoff

NewConstantBackoff creates a backoff that steps at constant intervals. This backoff will run "forever", use WithMaxRetries or a context to put a hard cap. This works similar to ConstantBackOff in github.com/cenkalti/backoff.

func Retry

func Retry(ctx context.Context, backoff wait.Backoff, retries int, operation func(context.Context) (bool, error), retryNotify func(error)) error

Retry executes an operation with retries following these semantics:

• The operation is executed at least once (even if context is cancelled)

• If operation returns nil error, assumption is that it succeeded

• If operation returns non-nil error, then the first boolean return value decides whether to retry or not

The operation will not be retried anymore if

• retries reaches 0

• the context is cancelled

The end result is:

• nil if operation was successful at least once
• last encountered error from operation if retries are exhausted
• a multi-error if context is cancelled that contains - the ctx.Err(), context.Cause() and last encountered error from the operation

If retryNotify is passed, it is called when making retries. Caveat: this function is similar to wait.ExponentialBackoff but has some important behavior differences like at-least-one execution and retryable errors.