rate_limitting_queue.go

/*
Copyright 2016 The Kubernetes Authors All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package workqueue

// RateLimitingInterface is an Interface that can Add an item at a later time.  This makes it easier to
// requeue items after failures without ending up in a hot-loop.
type RateLimitingInterface interface {
	DelayingInterface
	// AddRateLimited adds an item to the workqueue after the rate limiter says its ok
	AddRateLimited(item interface{})

	// Forget indicates that an item is finished being retried.  Doesn't matter whether its for perm failing
	// or for success, we'll stop the rate limiter from tracking it.  This only clears the `rateLimiter`, you
	// still have to call `Done` on the queue.
	Forget(item interface{})
	// NumRequeues returns back how many times the item was requeued
	NumRequeues(item interface{}) int
}

// NewRateLimitingQueue constructs a new workqueue with rateLimited queuing ability
// Remember to call Forget!  If you don't, you may end up tracking failures forever.
func NewRateLimitingQueue(rateLimiter RateLimiter) RateLimitingInterface {
	return &rateLimitingType{
		DelayingInterface: NewDelayingQueue(),
		rateLimiter:       rateLimiter,
	}
}

// rateLimitingType wraps an Interface and provides rateLimited re-enquing
type rateLimitingType struct {
	DelayingInterface

	rateLimiter RateLimiter
}

// AddRateLimited AddAfter's the item based on the time when the rate limiter says its ok
func (q *rateLimitingType) AddRateLimited(item interface{}) {
	q.DelayingInterface.AddAfter(item, q.rateLimiter.When(item))
}

func (q *rateLimitingType) NumRequeues(item interface{}) int {
	return q.rateLimiter.NumRequeues(item)
}

func (q *rateLimitingType) Forget(item interface{}) {
	q.rateLimiter.Forget(item)
}