workqueue

Documentation

Overview

Package workqueue provides a simple queue that supports the following features:

• Fair: items processed in the order in which they are added.
• Stingy: a single item will not be processed multiple times concurrently, and if an item is added multiple times before it can be processed, it will only be processed once.
• Multiple consumers and producers. In particular, it is allowed for an item to be reenqueued while it is being processed.
• Shutdown notifications.

Index

• func Parallelize(workers, pieces int, doWorkPiece DoWorkPieceFunc)
• func SetProvider(metricsProvider MetricsProvider)
• type BucketRateLimiter
  • func (r *BucketRateLimiter) Forget(item interface{})
  • func (r *BucketRateLimiter) NumRequeues(item interface{}) int
  • func (r *BucketRateLimiter) When(item interface{}) time.Duration
• type CounterMetric
• type DelayingInterface
  • func NewDelayingQueue() DelayingInterface
  • func NewNamedDelayingQueue(name string) DelayingInterface
• type DoWorkPieceFunc
• type GaugeMetric
• type Interface
• type ItemExponentialFailureRateLimiter
  • func (r *ItemExponentialFailureRateLimiter) Forget(item interface{})
  • func (r *ItemExponentialFailureRateLimiter) NumRequeues(item interface{}) int
  • func (r *ItemExponentialFailureRateLimiter) When(item interface{}) time.Duration
• type ItemFastSlowRateLimiter
  • func (r *ItemFastSlowRateLimiter) Forget(item interface{})
  • func (r *ItemFastSlowRateLimiter) NumRequeues(item interface{}) int
  • func (r *ItemFastSlowRateLimiter) When(item interface{}) time.Duration
• type MaxOfRateLimiter
  • func (r *MaxOfRateLimiter) Forget(item interface{})
  • func (r *MaxOfRateLimiter) NumRequeues(item interface{}) int
  • func (r *MaxOfRateLimiter) When(item interface{}) time.Duration
• type MetricsProvider
• type RateLimiter
  • func DefaultControllerRateLimiter() RateLimiter
  • func DefaultItemBasedRateLimiter() RateLimiter
  • func NewItemExponentialFailureRateLimiter(baseDelay time.Duration, maxDelay time.Duration) RateLimiter
  • func NewItemFastSlowRateLimiter(fastDelay, slowDelay time.Duration, maxFastAttempts int) RateLimiter
  • func NewMaxOfRateLimiter(limiters ...RateLimiter) RateLimiter
• type RateLimitingInterface
  • func NewNamedRateLimitingQueue(rateLimiter RateLimiter, name string) RateLimitingInterface
  • func NewRateLimitingQueue(rateLimiter RateLimiter) RateLimitingInterface
• type SummaryMetric
• type TimedWorkQueue
  • func NewTimedWorkQueue() *TimedWorkQueue
  • func (q TimedWorkQueue) Add(timedItem *TimedWorkQueueItem)
  • func (q TimedWorkQueue) Done(timedItem *TimedWorkQueueItem) error
  • func (q TimedWorkQueue) Get() (timedItem *TimedWorkQueueItem, shutdown bool)
• type TimedWorkQueueItem
• type Type
  • func New() *Type
  • func NewNamed(name string) *Type
  • func (q *Type) Add(item interface{})
  • func (q *Type) Done(item interface{})
  • func (q *Type) Get() (item interface{}, shutdown bool)
  • func (q *Type) Len() int
  • func (q *Type) ShutDown()
  • func (q *Type) ShuttingDown() bool

Functions

func Parallelize

func Parallelize(workers, pieces int, doWorkPiece DoWorkPieceFunc)

Parallelize is a very simple framework that allow for parallelizing N independent pieces of work.

func SetProvider

func SetProvider(metricsProvider MetricsProvider)

SetProvider sets the metrics provider of the metricsFactory.

Types

type BucketRateLimiter

type BucketRateLimiter struct {
	*ratelimit.Bucket
}

BucketRateLimiter adapts a standard bucket to the workqueue ratelimiter API

func (*BucketRateLimiter) Forget

func (r *BucketRateLimiter) Forget(item interface{})

func (*BucketRateLimiter) NumRequeues

func (r *BucketRateLimiter) NumRequeues(item interface{}) int

func (*BucketRateLimiter) When

func (r *BucketRateLimiter) When(item interface{}) time.Duration

type CounterMetric

type CounterMetric interface {
	Inc()
}

CounterMetric represents a single numerical value that only ever goes up.

type DelayingInterface

type DelayingInterface interface {
	Interface
	// AddAfter adds an item to the workqueue after the indicated duration has passed
	AddAfter(item interface{}, duration time.Duration)
}

DelayingInterface 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.

func NewDelayingQueue

func NewDelayingQueue() DelayingInterface

NewDelayingQueue constructs a new workqueue with delayed queuing ability

func NewNamedDelayingQueue

func NewNamedDelayingQueue(name string) DelayingInterface

type DoWorkPieceFunc

type DoWorkPieceFunc func(piece int)

type GaugeMetric

type GaugeMetric interface {
	Inc()
	Dec()
}

GaugeMetric represents a single numerical value that can arbitrarily go up and down.

type Interface

type Interface interface {
	Add(item interface{})
	Len() int
	Get() (item interface{}, shutdown bool)
	Done(item interface{})
	ShutDown()
	ShuttingDown() bool
}

type ItemExponentialFailureRateLimiter

type ItemExponentialFailureRateLimiter struct {
	// contains filtered or unexported fields
}

ItemExponentialFailureRateLimiter does a simple baseDelay*10^<num-failures> limit dealing with max failures and expiration are up to the caller

func (*ItemExponentialFailureRateLimiter) Forget

func (r *ItemExponentialFailureRateLimiter) Forget(item interface{})

func (*ItemExponentialFailureRateLimiter) NumRequeues

func (r *ItemExponentialFailureRateLimiter) NumRequeues(item interface{}) int

func (*ItemExponentialFailureRateLimiter) When

func (r *ItemExponentialFailureRateLimiter) When(item interface{}) time.Duration

type ItemFastSlowRateLimiter

type ItemFastSlowRateLimiter struct {
	// contains filtered or unexported fields
}

ItemFastSlowRateLimiter does a quick retry for a certain number of attempts, then a slow retry after that

func (*ItemFastSlowRateLimiter) Forget

func (r *ItemFastSlowRateLimiter) Forget(item interface{})

func (*ItemFastSlowRateLimiter) NumRequeues

func (r *ItemFastSlowRateLimiter) NumRequeues(item interface{}) int

func (*ItemFastSlowRateLimiter) When

func (r *ItemFastSlowRateLimiter) When(item interface{}) time.Duration

type MaxOfRateLimiter

type MaxOfRateLimiter struct {
	// contains filtered or unexported fields
}

MaxOfRateLimiter calls every RateLimiter and returns the worst case response When used with a token bucket limiter, the burst could be apparently exceeded in cases where particular items were separately delayed a longer time.

func (*MaxOfRateLimiter) Forget

func (r *MaxOfRateLimiter) Forget(item interface{})

func (*MaxOfRateLimiter) NumRequeues

func (r *MaxOfRateLimiter) NumRequeues(item interface{}) int

func (*MaxOfRateLimiter) When

func (r *MaxOfRateLimiter) When(item interface{}) time.Duration

type MetricsProvider

type MetricsProvider interface {
	NewDepthMetric(name string) GaugeMetric
	NewAddsMetric(name string) CounterMetric
	NewLatencyMetric(name string) SummaryMetric
	NewWorkDurationMetric(name string) SummaryMetric
	NewRetriesMetric(name string) CounterMetric
}

MetricsProvider generates various metrics used by the queue.

type RateLimiter

type RateLimiter interface {
	// When gets an item and gets to decide how long that item should wait
	When(item interface{}) time.Duration
	// Forget indicates that an item is finished being retried.  Doesn't matter whether its for perm failing
	// or for success, we'll stop tracking it
	Forget(item interface{})
	// NumRequeues returns back how many failures the item has had
	NumRequeues(item interface{}) int
}

func DefaultControllerRateLimiter

func DefaultControllerRateLimiter() RateLimiter

DefaultControllerRateLimiter is a no-arg constructor for a default rate limiter for a workqueue. It has both overall and per-item rate limitting. The overall is a token bucket and the per-item is exponential

func DefaultItemBasedRateLimiter

func DefaultItemBasedRateLimiter() RateLimiter

func NewItemExponentialFailureRateLimiter

func NewItemExponentialFailureRateLimiter(baseDelay time.Duration, maxDelay time.Duration) RateLimiter

func NewItemFastSlowRateLimiter

func NewItemFastSlowRateLimiter(fastDelay, slowDelay time.Duration, maxFastAttempts int) RateLimiter

func NewMaxOfRateLimiter

func NewMaxOfRateLimiter(limiters ...RateLimiter) RateLimiter

type RateLimitingInterface

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
}

RateLimitingInterface is an interface that rate limits items being added to the queue.

func NewNamedRateLimitingQueue

func NewNamedRateLimitingQueue(rateLimiter RateLimiter, name string) RateLimitingInterface

func NewRateLimitingQueue

func NewRateLimitingQueue(rateLimiter RateLimiter) RateLimitingInterface

NewRateLimitingQueue constructs a new workqueue with rateLimited queuing ability Remember to call Forget! If you don't, you may end up tracking failures forever.

type SummaryMetric

type SummaryMetric interface {
	Observe(float64)
}

SummaryMetric captures individual observations.

type TimedWorkQueue

type TimedWorkQueue struct {
	*Type
}

func NewTimedWorkQueue

func NewTimedWorkQueue() *TimedWorkQueue

func (TimedWorkQueue) Add

func (q TimedWorkQueue) Add(timedItem *TimedWorkQueueItem)

Add adds the obj along with the current timestamp to the queue.

func (TimedWorkQueue) Done

func (q TimedWorkQueue) Done(timedItem *TimedWorkQueueItem) error

func (TimedWorkQueue) Get

func (q TimedWorkQueue) Get() (timedItem *TimedWorkQueueItem, shutdown bool)

Get gets the obj along with its timestamp from the queue.

type TimedWorkQueueItem

type TimedWorkQueueItem struct {
	StartTime time.Time
	Object    interface{}
}

type Type

type Type struct {
	// contains filtered or unexported fields
}

Type is a work queue (see the package comment).

func New

func New() *Type

New constructs a new workqueue (see the package comment).

func NewNamed

func NewNamed(name string) *Type

func (*Type) Add

func (q *Type) Add(item interface{})

Add marks item as needing processing.

func (*Type) Done

func (q *Type) Done(item interface{})

Done marks item as done processing, and if it has been marked as dirty again while it was being processed, it will be re-added to the queue for re-processing.

func (*Type) Get

func (q *Type) Get() (item interface{}, shutdown bool)

Get blocks until it can return an item to be processed. If shutdown = true, the caller should end their goroutine. You must call Done with item when you have finished processing it.

func (*Type) Len

func (q *Type) Len() int

Len returns the current queue length, for informational purposes only. You shouldn't e.g. gate a call to Add() or Get() on Len() being a particular value, that can't be synchronized properly.

func (*Type) ShutDown

func (q *Type) ShutDown()

ShutDown will cause q to ignore all new items added to it. As soon as the worker goroutines have drained the existing items in the queue, they will be instructed to exit.

func (*Type) ShuttingDown

func (q *Type) ShuttingDown() bool