added vendors

vendor/k8s.io/client-go/util/workqueue/BUILD

@@ -0,0 +1,59 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+    "go_test",
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = [
+        "default_rate_limiters_test.go",
+        "delaying_queue_test.go",
+        "rate_limitting_queue_test.go",
+    ],
+    embed = [":go_default_library"],
+    deps = [
+        "//vendor/k8s.io/apimachinery/pkg/util/clock:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/wait:go_default_library",
+    ],
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "default_rate_limiters.go",
+        "delaying_queue.go",
+        "doc.go",
+        "metrics.go",
+        "parallelizer.go",
+        "queue.go",
+        "rate_limitting_queue.go",
+    ],
+    importpath = "k8s.io/client-go/util/workqueue",
+    deps = [
+        "//vendor/golang.org/x/time/rate:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/clock:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_xtest",
+    srcs = ["queue_test.go"],
+    deps = ["//vendor/k8s.io/client-go/util/workqueue:go_default_library"],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+)

vendor/k8s.io/client-go/util/workqueue/default_rate_limiters.go

@@ -0,0 +1,211 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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
+
+import (
+	"math"
+	"sync"
+	"time"
+
+	"golang.org/x/time/rate"
+)
+
+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
+}
+
+// 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 DefaultControllerRateLimiter() RateLimiter {
+	return NewMaxOfRateLimiter(
+		NewItemExponentialFailureRateLimiter(5*time.Millisecond, 1000*time.Second),
+		// 10 qps, 100 bucket size.  This is only for retry speed and its only the overall factor (not per item)
+		&BucketRateLimiter{Limiter: rate.NewLimiter(rate.Limit(10), 100)},
+	)
+}
+
+// BucketRateLimiter adapts a standard bucket to the workqueue ratelimiter API
+type BucketRateLimiter struct {
+	*rate.Limiter
+}
+
+var _ RateLimiter = &BucketRateLimiter{}
+
+func (r *BucketRateLimiter) When(item interface{}) time.Duration {
+	return r.Limiter.Reserve().Delay()
+}
+
+func (r *BucketRateLimiter) NumRequeues(item interface{}) int {
+	return 0
+}
+
+func (r *BucketRateLimiter) Forget(item interface{}) {
+}
+
+// ItemExponentialFailureRateLimiter does a simple baseDelay*10^<num-failures> limit
+// dealing with max failures and expiration are up to the caller
+type ItemExponentialFailureRateLimiter struct {
+	failuresLock sync.Mutex
+	failures     map[interface{}]int
+
+	baseDelay time.Duration
+	maxDelay  time.Duration
+}
+
+var _ RateLimiter = &ItemExponentialFailureRateLimiter{}
+
+func NewItemExponentialFailureRateLimiter(baseDelay time.Duration, maxDelay time.Duration) RateLimiter {
+	return &ItemExponentialFailureRateLimiter{
+		failures:  map[interface{}]int{},
+		baseDelay: baseDelay,
+		maxDelay:  maxDelay,
+	}
+}
+
+func DefaultItemBasedRateLimiter() RateLimiter {
+	return NewItemExponentialFailureRateLimiter(time.Millisecond, 1000*time.Second)
+}
+
+func (r *ItemExponentialFailureRateLimiter) When(item interface{}) time.Duration {
+	r.failuresLock.Lock()
+	defer r.failuresLock.Unlock()
+
+	exp := r.failures[item]
+	r.failures[item] = r.failures[item] + 1
+
+	// The backoff is capped such that 'calculated' value never overflows.
+	backoff := float64(r.baseDelay.Nanoseconds()) * math.Pow(2, float64(exp))
+	if backoff > math.MaxInt64 {
+		return r.maxDelay
+	}
+
+	calculated := time.Duration(backoff)
+	if calculated > r.maxDelay {
+		return r.maxDelay
+	}
+
+	return calculated
+}
+
+func (r *ItemExponentialFailureRateLimiter) NumRequeues(item interface{}) int {
+	r.failuresLock.Lock()
+	defer r.failuresLock.Unlock()
+
+	return r.failures[item]
+}
+
+func (r *ItemExponentialFailureRateLimiter) Forget(item interface{}) {
+	r.failuresLock.Lock()
+	defer r.failuresLock.Unlock()
+
+	delete(r.failures, item)
+}
+
+// ItemFastSlowRateLimiter does a quick retry for a certain number of attempts, then a slow retry after that
+type ItemFastSlowRateLimiter struct {
+	failuresLock sync.Mutex
+	failures     map[interface{}]int
+
+	maxFastAttempts int
+	fastDelay       time.Duration
+	slowDelay       time.Duration
+}
+
+var _ RateLimiter = &ItemFastSlowRateLimiter{}
+
+func NewItemFastSlowRateLimiter(fastDelay, slowDelay time.Duration, maxFastAttempts int) RateLimiter {
+	return &ItemFastSlowRateLimiter{
+		failures:        map[interface{}]int{},
+		fastDelay:       fastDelay,
+		slowDelay:       slowDelay,
+		maxFastAttempts: maxFastAttempts,
+	}
+}
+
+func (r *ItemFastSlowRateLimiter) When(item interface{}) time.Duration {
+	r.failuresLock.Lock()
+	defer r.failuresLock.Unlock()
+
+	r.failures[item] = r.failures[item] + 1
+
+	if r.failures[item] <= r.maxFastAttempts {
+		return r.fastDelay
+	}
+
+	return r.slowDelay
+}
+
+func (r *ItemFastSlowRateLimiter) NumRequeues(item interface{}) int {
+	r.failuresLock.Lock()
+	defer r.failuresLock.Unlock()
+
+	return r.failures[item]
+}
+
+func (r *ItemFastSlowRateLimiter) Forget(item interface{}) {
+	r.failuresLock.Lock()
+	defer r.failuresLock.Unlock()
+
+	delete(r.failures, item)
+}
+
+// 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.
+type MaxOfRateLimiter struct {
+	limiters []RateLimiter
+}
+
+func (r *MaxOfRateLimiter) When(item interface{}) time.Duration {
+	ret := time.Duration(0)
+	for _, limiter := range r.limiters {
+		curr := limiter.When(item)
+		if curr > ret {
+			ret = curr
+		}
+	}
+
+	return ret
+}
+
+func NewMaxOfRateLimiter(limiters ...RateLimiter) RateLimiter {
+	return &MaxOfRateLimiter{limiters: limiters}
+}
+
+func (r *MaxOfRateLimiter) NumRequeues(item interface{}) int {
+	ret := 0
+	for _, limiter := range r.limiters {
+		curr := limiter.NumRequeues(item)
+		if curr > ret {
+			ret = curr
+		}
+	}
+
+	return ret
+}
+
+func (r *MaxOfRateLimiter) Forget(item interface{}) {
+	for _, limiter := range r.limiters {
+		limiter.Forget(item)
+	}
+}

vendor/k8s.io/client-go/util/workqueue/default_rate_limiters_test.go

@@ -0,0 +1,184 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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
+
+import (
+	"testing"
+	"time"
+)
+
+func TestItemExponentialFailureRateLimiter(t *testing.T) {
+	limiter := NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Second)
+
+	if e, a := 1*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 2*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 4*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 8*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 16*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5, limiter.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	if e, a := 1*time.Millisecond, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 2*time.Millisecond, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 2, limiter.NumRequeues("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	limiter.Forget("one")
+	if e, a := 0, limiter.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 1*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+}
+
+func TestItemExponentialFailureRateLimiterOverFlow(t *testing.T) {
+	limiter := NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1000*time.Second)
+	for i := 0; i < 5; i++ {
+		limiter.When("one")
+	}
+	if e, a := 32*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	for i := 0; i < 1000; i++ {
+		limiter.When("overflow1")
+	}
+	if e, a := 1000*time.Second, limiter.When("overflow1"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	limiter = NewItemExponentialFailureRateLimiter(1*time.Minute, 1000*time.Hour)
+	for i := 0; i < 2; i++ {
+		limiter.When("two")
+	}
+	if e, a := 4*time.Minute, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	for i := 0; i < 1000; i++ {
+		limiter.When("overflow2")
+	}
+	if e, a := 1000*time.Hour, limiter.When("overflow2"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+}
+
+func TestItemFastSlowRateLimiter(t *testing.T) {
+	limiter := NewItemFastSlowRateLimiter(5*time.Millisecond, 10*time.Second, 3)
+
+	if e, a := 5*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 10*time.Second, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 10*time.Second, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5, limiter.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	if e, a := 5*time.Millisecond, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5*time.Millisecond, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 2, limiter.NumRequeues("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	limiter.Forget("one")
+	if e, a := 0, limiter.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+}
+
+func TestMaxOfRateLimiter(t *testing.T) {
+	limiter := NewMaxOfRateLimiter(
+		NewItemFastSlowRateLimiter(5*time.Millisecond, 3*time.Second, 3),
+		NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Second),
+	)
+
+	if e, a := 5*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 3*time.Second, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 3*time.Second, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5, limiter.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	if e, a := 5*time.Millisecond, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5*time.Millisecond, limiter.When("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 2, limiter.NumRequeues("two"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	limiter.Forget("one")
+	if e, a := 0, limiter.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 5*time.Millisecond, limiter.When("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+}

vendor/k8s.io/client-go/util/workqueue/delaying_queue.go

@@ -0,0 +1,257 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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
+
+import (
+	"container/heap"
+	"time"
+
+	"k8s.io/apimachinery/pkg/util/clock"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+)
+
+// 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.
+type DelayingInterface interface {
+	Interface
+	// AddAfter adds an item to the workqueue after the indicated duration has passed
+	AddAfter(item interface{}, duration time.Duration)
+}
+
+// NewDelayingQueue constructs a new workqueue with delayed queuing ability
+func NewDelayingQueue() DelayingInterface {
+	return newDelayingQueue(clock.RealClock{}, "")
+}
+
+func NewNamedDelayingQueue(name string) DelayingInterface {
+	return newDelayingQueue(clock.RealClock{}, name)
+}
+
+func newDelayingQueue(clock clock.Clock, name string) DelayingInterface {
+	ret := &delayingType{
+		Interface:       NewNamed(name),
+		clock:           clock,
+		heartbeat:       clock.Tick(maxWait),
+		stopCh:          make(chan struct{}),
+		waitingForAddCh: make(chan *waitFor, 1000),
+		metrics:         newRetryMetrics(name),
+	}
+
+	go ret.waitingLoop()
+
+	return ret
+}
+
+// delayingType wraps an Interface and provides delayed re-enquing
+type delayingType struct {
+	Interface
+
+	// clock tracks time for delayed firing
+	clock clock.Clock
+
+	// stopCh lets us signal a shutdown to the waiting loop
+	stopCh chan struct{}
+
+	// heartbeat ensures we wait no more than maxWait before firing
+	//
+	// TODO: replace with Ticker (and add to clock) so this can be cleaned up.
+	// clock.Tick will leak.
+	heartbeat <-chan time.Time
+
+	// waitingForAddCh is a buffered channel that feeds waitingForAdd
+	waitingForAddCh chan *waitFor
+
+	// metrics counts the number of retries
+	metrics retryMetrics
+}
+
+// waitFor holds the data to add and the time it should be added
+type waitFor struct {
+	data    t
+	readyAt time.Time
+	// index in the priority queue (heap)
+	index int
+}
+
+// waitForPriorityQueue implements a priority queue for waitFor items.
+//
+// waitForPriorityQueue implements heap.Interface. The item occurring next in
+// time (i.e., the item with the smallest readyAt) is at the root (index 0).
+// Peek returns this minimum item at index 0. Pop returns the minimum item after
+// it has been removed from the queue and placed at index Len()-1 by
+// container/heap. Push adds an item at index Len(), and container/heap
+// percolates it into the correct location.
+type waitForPriorityQueue []*waitFor
+
+func (pq waitForPriorityQueue) Len() int {
+	return len(pq)
+}
+func (pq waitForPriorityQueue) Less(i, j int) bool {
+	return pq[i].readyAt.Before(pq[j].readyAt)
+}
+func (pq waitForPriorityQueue) Swap(i, j int) {
+	pq[i], pq[j] = pq[j], pq[i]
+	pq[i].index = i
+	pq[j].index = j
+}
+
+// Push adds an item to the queue. Push should not be called directly; instead,
+// use `heap.Push`.
+func (pq *waitForPriorityQueue) Push(x interface{}) {
+	n := len(*pq)
+	item := x.(*waitFor)
+	item.index = n
+	*pq = append(*pq, item)
+}
+
+// Pop removes an item from the queue. Pop should not be called directly;
+// instead, use `heap.Pop`.
+func (pq *waitForPriorityQueue) Pop() interface{} {
+	n := len(*pq)
+	item := (*pq)[n-1]
+	item.index = -1
+	*pq = (*pq)[0:(n - 1)]
+	return item
+}
+
+// Peek returns the item at the beginning of the queue, without removing the
+// item or otherwise mutating the queue. It is safe to call directly.
+func (pq waitForPriorityQueue) Peek() interface{} {
+	return pq[0]
+}
+
+// ShutDown gives a way to shut off this queue
+func (q *delayingType) ShutDown() {
+	q.Interface.ShutDown()
+	close(q.stopCh)
+}
+
+// AddAfter adds the given item to the work queue after the given delay
+func (q *delayingType) AddAfter(item interface{}, duration time.Duration) {
+	// don't add if we're already shutting down
+	if q.ShuttingDown() {
+		return
+	}
+
+	q.metrics.retry()
+
+	// immediately add things with no delay
+	if duration <= 0 {
+		q.Add(item)
+		return
+	}
+
+	select {
+	case <-q.stopCh:
+		// unblock if ShutDown() is called
+	case q.waitingForAddCh <- &waitFor{data: item, readyAt: q.clock.Now().Add(duration)}:
+	}
+}
+
+// maxWait keeps a max bound on the wait time. It's just insurance against weird things happening.
+// Checking the queue every 10 seconds isn't expensive and we know that we'll never end up with an
+// expired item sitting for more than 10 seconds.
+const maxWait = 10 * time.Second
+
+// waitingLoop runs until the workqueue is shutdown and keeps a check on the list of items to be added.
+func (q *delayingType) waitingLoop() {
+	defer utilruntime.HandleCrash()
+
+	// Make a placeholder channel to use when there are no items in our list
+	never := make(<-chan time.Time)
+
+	waitingForQueue := &waitForPriorityQueue{}
+	heap.Init(waitingForQueue)
+
+	waitingEntryByData := map[t]*waitFor{}
+
+	for {
+		if q.Interface.ShuttingDown() {
+			return
+		}
+
+		now := q.clock.Now()
+
+		// Add ready entries
+		for waitingForQueue.Len() > 0 {
+			entry := waitingForQueue.Peek().(*waitFor)
+			if entry.readyAt.After(now) {
+				break
+			}
+
+			entry = heap.Pop(waitingForQueue).(*waitFor)
+			q.Add(entry.data)
+			delete(waitingEntryByData, entry.data)
+		}
+
+		// Set up a wait for the first item's readyAt (if one exists)
+		nextReadyAt := never
+		if waitingForQueue.Len() > 0 {
+			entry := waitingForQueue.Peek().(*waitFor)
+			nextReadyAt = q.clock.After(entry.readyAt.Sub(now))
+		}
+
+		select {
+		case <-q.stopCh:
+			return
+
+		case <-q.heartbeat:
+			// continue the loop, which will add ready items
+
+		case <-nextReadyAt:
+			// continue the loop, which will add ready items
+
+		case waitEntry := <-q.waitingForAddCh:
+			if waitEntry.readyAt.After(q.clock.Now()) {
+				insert(waitingForQueue, waitingEntryByData, waitEntry)
+			} else {
+				q.Add(waitEntry.data)
+			}
+
+			drained := false
+			for !drained {
+				select {
+				case waitEntry := <-q.waitingForAddCh:
+					if waitEntry.readyAt.After(q.clock.Now()) {
+						insert(waitingForQueue, waitingEntryByData, waitEntry)
+					} else {
+						q.Add(waitEntry.data)
+					}
+				default:
+					drained = true
+				}
+			}
+		}
+	}
+}
+
+// insert adds the entry to the priority queue, or updates the readyAt if it already exists in the queue
+func insert(q *waitForPriorityQueue, knownEntries map[t]*waitFor, entry *waitFor) {
+	// if the entry already exists, update the time only if it would cause the item to be queued sooner
+	existing, exists := knownEntries[entry.data]
+	if exists {
+		if existing.readyAt.After(entry.readyAt) {
+			existing.readyAt = entry.readyAt
+			heap.Fix(q, existing.index)
+		}
+
+		return
+	}
+
+	heap.Push(q, entry)
+	knownEntries[entry.data] = entry
+}

vendor/k8s.io/client-go/util/workqueue/delaying_queue_test.go

@@ -0,0 +1,255 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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
+
+import (
+	"fmt"
+	"math/rand"
+	"reflect"
+	"testing"
+	"time"
+
+	"k8s.io/apimachinery/pkg/util/clock"
+	"k8s.io/apimachinery/pkg/util/wait"
+)
+
+func TestSimpleQueue(t *testing.T) {
+	fakeClock := clock.NewFakeClock(time.Now())
+	q := newDelayingQueue(fakeClock, "")
+
+	first := "foo"
+
+	q.AddAfter(first, 50*time.Millisecond)
+	if err := waitForWaitingQueueToFill(q); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+
+	if q.Len() != 0 {
+		t.Errorf("should not have added")
+	}
+
+	fakeClock.Step(60 * time.Millisecond)
+
+	if err := waitForAdded(q, 1); err != nil {
+		t.Errorf("should have added")
+	}
+	item, _ := q.Get()
+	q.Done(item)
+
+	// step past the next heartbeat
+	fakeClock.Step(10 * time.Second)
+
+	err := wait.Poll(1*time.Millisecond, 30*time.Millisecond, func() (done bool, err error) {
+		if q.Len() > 0 {
+			return false, fmt.Errorf("added to queue")
+		}
+
+		return false, nil
+	})
+	if err != wait.ErrWaitTimeout {
+		t.Errorf("expected timeout, got: %v", err)
+	}
+
+	if q.Len() != 0 {
+		t.Errorf("should not have added")
+	}
+}
+
+func TestDeduping(t *testing.T) {
+	fakeClock := clock.NewFakeClock(time.Now())
+	q := newDelayingQueue(fakeClock, "")
+
+	first := "foo"
+
+	q.AddAfter(first, 50*time.Millisecond)
+	if err := waitForWaitingQueueToFill(q); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+	q.AddAfter(first, 70*time.Millisecond)
+	if err := waitForWaitingQueueToFill(q); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+	if q.Len() != 0 {
+		t.Errorf("should not have added")
+	}
+
+	// step past the first block, we should receive now
+	fakeClock.Step(60 * time.Millisecond)
+	if err := waitForAdded(q, 1); err != nil {
+		t.Errorf("should have added")
+	}
+	item, _ := q.Get()
+	q.Done(item)
+
+	// step past the second add
+	fakeClock.Step(20 * time.Millisecond)
+	if q.Len() != 0 {
+		t.Errorf("should not have added")
+	}
+
+	// test again, but this time the earlier should override
+	q.AddAfter(first, 50*time.Millisecond)
+	q.AddAfter(first, 30*time.Millisecond)
+	if err := waitForWaitingQueueToFill(q); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+	if q.Len() != 0 {
+		t.Errorf("should not have added")
+	}
+
+	fakeClock.Step(40 * time.Millisecond)
+	if err := waitForAdded(q, 1); err != nil {
+		t.Errorf("should have added")
+	}
+	item, _ = q.Get()
+	q.Done(item)
+
+	// step past the second add
+	fakeClock.Step(20 * time.Millisecond)
+	if q.Len() != 0 {
+		t.Errorf("should not have added")
+	}
+	if q.Len() != 0 {
+		t.Errorf("should not have added")
+	}
+}
+
+func TestAddTwoFireEarly(t *testing.T) {
+	fakeClock := clock.NewFakeClock(time.Now())
+	q := newDelayingQueue(fakeClock, "")
+
+	first := "foo"
+	second := "bar"
+	third := "baz"
+
+	q.AddAfter(first, 1*time.Second)
+	q.AddAfter(second, 50*time.Millisecond)
+	if err := waitForWaitingQueueToFill(q); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+
+	if q.Len() != 0 {
+		t.Errorf("should not have added")
+	}
+
+	fakeClock.Step(60 * time.Millisecond)
+
+	if err := waitForAdded(q, 1); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+	item, _ := q.Get()
+	if !reflect.DeepEqual(item, second) {
+		t.Errorf("expected %v, got %v", second, item)
+	}
+
+	q.AddAfter(third, 2*time.Second)
+
+	fakeClock.Step(1 * time.Second)
+	if err := waitForAdded(q, 1); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+	item, _ = q.Get()
+	if !reflect.DeepEqual(item, first) {
+		t.Errorf("expected %v, got %v", first, item)
+	}
+
+	fakeClock.Step(2 * time.Second)
+	if err := waitForAdded(q, 1); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+	item, _ = q.Get()
+	if !reflect.DeepEqual(item, third) {
+		t.Errorf("expected %v, got %v", third, item)
+	}
+}
+
+func TestCopyShifting(t *testing.T) {
+	fakeClock := clock.NewFakeClock(time.Now())
+	q := newDelayingQueue(fakeClock, "")
+
+	first := "foo"
+	second := "bar"
+	third := "baz"
+
+	q.AddAfter(first, 1*time.Second)
+	q.AddAfter(second, 500*time.Millisecond)
+	q.AddAfter(third, 250*time.Millisecond)
+	if err := waitForWaitingQueueToFill(q); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+
+	if q.Len() != 0 {
+		t.Errorf("should not have added")
+	}
+
+	fakeClock.Step(2 * time.Second)
+
+	if err := waitForAdded(q, 3); err != nil {
+		t.Fatalf("unexpected err: %v", err)
+	}
+	actualFirst, _ := q.Get()
+	if !reflect.DeepEqual(actualFirst, third) {
+		t.Errorf("expected %v, got %v", third, actualFirst)
+	}
+	actualSecond, _ := q.Get()
+	if !reflect.DeepEqual(actualSecond, second) {
+		t.Errorf("expected %v, got %v", second, actualSecond)
+	}
+	actualThird, _ := q.Get()
+	if !reflect.DeepEqual(actualThird, first) {
+		t.Errorf("expected %v, got %v", first, actualThird)
+	}
+}
+
+func BenchmarkDelayingQueue_AddAfter(b *testing.B) {
+	r := rand.New(rand.NewSource(time.Now().Unix()))
+
+	fakeClock := clock.NewFakeClock(time.Now())
+	q := newDelayingQueue(fakeClock, "")
+
+	// Add items
+	for n := 0; n < b.N; n++ {
+		data := fmt.Sprintf("%d", n)
+		q.AddAfter(data, time.Duration(r.Int63n(int64(10*time.Minute))))
+	}
+
+	// Exercise item removal as well
+	fakeClock.Step(11 * time.Minute)
+	for n := 0; n < b.N; n++ {
+		_, _ = q.Get()
+	}
+}
+
+func waitForAdded(q DelayingInterface, depth int) error {
+	return wait.Poll(1*time.Millisecond, 10*time.Second, func() (done bool, err error) {
+		if q.Len() == depth {
+			return true, nil
+		}
+
+		return false, nil
+	})
+}
+
+func waitForWaitingQueueToFill(q DelayingInterface) error {
+	return wait.Poll(1*time.Millisecond, 10*time.Second, func() (done bool, err error) {
+		if len(q.(*delayingType).waitingForAddCh) == 0 {
+			return true, nil
+		}
+
+		return false, nil
+	})
+}

vendor/k8s.io/client-go/util/workqueue/doc.go

@@ -0,0 +1,26 @@
+/*
+Copyright 2014 The Kubernetes Authors.
+
+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 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.
+package workqueue

vendor/k8s.io/client-go/util/workqueue/metrics.go

@@ -0,0 +1,195 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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
+
+import (
+	"sync"
+	"time"
+)
+
+// This file provides abstractions for setting the provider (e.g., prometheus)
+// of metrics.
+
+type queueMetrics interface {
+	add(item t)
+	get(item t)
+	done(item t)
+}
+
+// GaugeMetric represents a single numerical value that can arbitrarily go up
+// and down.
+type GaugeMetric interface {
+	Inc()
+	Dec()
+}
+
+// CounterMetric represents a single numerical value that only ever
+// goes up.
+type CounterMetric interface {
+	Inc()
+}
+
+// SummaryMetric captures individual observations.
+type SummaryMetric interface {
+	Observe(float64)
+}
+
+type noopMetric struct{}
+
+func (noopMetric) Inc()            {}
+func (noopMetric) Dec()            {}
+func (noopMetric) Observe(float64) {}
+
+type defaultQueueMetrics struct {
+	// current depth of a workqueue
+	depth GaugeMetric
+	// total number of adds handled by a workqueue
+	adds CounterMetric
+	// how long an item stays in a workqueue
+	latency SummaryMetric
+	// how long processing an item from a workqueue takes
+	workDuration         SummaryMetric
+	addTimes             map[t]time.Time
+	processingStartTimes map[t]time.Time
+}
+
+func (m *defaultQueueMetrics) add(item t) {
+	if m == nil {
+		return
+	}
+
+	m.adds.Inc()
+	m.depth.Inc()
+	if _, exists := m.addTimes[item]; !exists {
+		m.addTimes[item] = time.Now()
+	}
+}
+
+func (m *defaultQueueMetrics) get(item t) {
+	if m == nil {
+		return
+	}
+
+	m.depth.Dec()
+	m.processingStartTimes[item] = time.Now()
+	if startTime, exists := m.addTimes[item]; exists {
+		m.latency.Observe(sinceInMicroseconds(startTime))
+		delete(m.addTimes, item)
+	}
+}
+
+func (m *defaultQueueMetrics) done(item t) {
+	if m == nil {
+		return
+	}
+
+	if startTime, exists := m.processingStartTimes[item]; exists {
+		m.workDuration.Observe(sinceInMicroseconds(startTime))
+		delete(m.processingStartTimes, item)
+	}
+}
+
+// Gets the time since the specified start in microseconds.
+func sinceInMicroseconds(start time.Time) float64 {
+	return float64(time.Since(start).Nanoseconds() / time.Microsecond.Nanoseconds())
+}
+
+type retryMetrics interface {
+	retry()
+}
+
+type defaultRetryMetrics struct {
+	retries CounterMetric
+}
+
+func (m *defaultRetryMetrics) retry() {
+	if m == nil {
+		return
+	}
+
+	m.retries.Inc()
+}
+
+// MetricsProvider generates various metrics used by the queue.
+type MetricsProvider interface {
+	NewDepthMetric(name string) GaugeMetric
+	NewAddsMetric(name string) CounterMetric
+	NewLatencyMetric(name string) SummaryMetric
+	NewWorkDurationMetric(name string) SummaryMetric
+	NewRetriesMetric(name string) CounterMetric
+}
+
+type noopMetricsProvider struct{}
+
+func (_ noopMetricsProvider) NewDepthMetric(name string) GaugeMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewAddsMetric(name string) CounterMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewLatencyMetric(name string) SummaryMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewWorkDurationMetric(name string) SummaryMetric {
+	return noopMetric{}
+}
+
+func (_ noopMetricsProvider) NewRetriesMetric(name string) CounterMetric {
+	return noopMetric{}
+}
+
+var metricsFactory = struct {
+	metricsProvider MetricsProvider
+	setProviders    sync.Once
+}{
+	metricsProvider: noopMetricsProvider{},
+}
+
+func newQueueMetrics(name string) queueMetrics {
+	var ret *defaultQueueMetrics
+	if len(name) == 0 {
+		return ret
+	}
+	return &defaultQueueMetrics{
+		depth:                metricsFactory.metricsProvider.NewDepthMetric(name),
+		adds:                 metricsFactory.metricsProvider.NewAddsMetric(name),
+		latency:              metricsFactory.metricsProvider.NewLatencyMetric(name),
+		workDuration:         metricsFactory.metricsProvider.NewWorkDurationMetric(name),
+		addTimes:             map[t]time.Time{},
+		processingStartTimes: map[t]time.Time{},
+	}
+}
+
+func newRetryMetrics(name string) retryMetrics {
+	var ret *defaultRetryMetrics
+	if len(name) == 0 {
+		return ret
+	}
+	return &defaultRetryMetrics{
+		retries: metricsFactory.metricsProvider.NewRetriesMetric(name),
+	}
+}
+
+// SetProvider sets the metrics provider of the metricsFactory.
+func SetProvider(metricsProvider MetricsProvider) {
+	metricsFactory.setProviders.Do(func() {
+		metricsFactory.metricsProvider = metricsProvider
+	})
+}

vendor/k8s.io/client-go/util/workqueue/parallelizer.go

@@ -0,0 +1,52 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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
+
+import (
+	"sync"
+
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+)
+
+type DoWorkPieceFunc func(piece int)
+
+// Parallelize is a very simple framework that allow for parallelizing
+// N independent pieces of work.
+func Parallelize(workers, pieces int, doWorkPiece DoWorkPieceFunc) {
+	toProcess := make(chan int, pieces)
+	for i := 0; i < pieces; i++ {
+		toProcess <- i
+	}
+	close(toProcess)
+
+	if pieces < workers {
+		workers = pieces
+	}
+
+	wg := sync.WaitGroup{}
+	wg.Add(workers)
+	for i := 0; i < workers; i++ {
+		go func() {
+			defer utilruntime.HandleCrash()
+			defer wg.Done()
+			for piece := range toProcess {
+				doWorkPiece(piece)
+			}
+		}()
+	}
+	wg.Wait()
+}

vendor/k8s.io/client-go/util/workqueue/queue.go

@@ -0,0 +1,172 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+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
+
+import (
+	"sync"
+)
+
+type Interface interface {
+	Add(item interface{})
+	Len() int
+	Get() (item interface{}, shutdown bool)
+	Done(item interface{})
+	ShutDown()
+	ShuttingDown() bool
+}
+
+// New constructs a new work queue (see the package comment).
+func New() *Type {
+	return NewNamed("")
+}
+
+func NewNamed(name string) *Type {
+	return &Type{
+		dirty:      set{},
+		processing: set{},
+		cond:       sync.NewCond(&sync.Mutex{}),
+		metrics:    newQueueMetrics(name),
+	}
+}
+
+// Type is a work queue (see the package comment).
+type Type struct {
+	// queue defines the order in which we will work on items. Every
+	// element of queue should be in the dirty set and not in the
+	// processing set.
+	queue []t
+
+	// dirty defines all of the items that need to be processed.
+	dirty set
+
+	// Things that are currently being processed are in the processing set.
+	// These things may be simultaneously in the dirty set. When we finish
+	// processing something and remove it from this set, we'll check if
+	// it's in the dirty set, and if so, add it to the queue.
+	processing set
+
+	cond *sync.Cond
+
+	shuttingDown bool
+
+	metrics queueMetrics
+}
+
+type empty struct{}
+type t interface{}
+type set map[t]empty
+
+func (s set) has(item t) bool {
+	_, exists := s[item]
+	return exists
+}
+
+func (s set) insert(item t) {
+	s[item] = empty{}
+}
+
+func (s set) delete(item t) {
+	delete(s, item)
+}
+
+// Add marks item as needing processing.
+func (q *Type) Add(item interface{}) {
+	q.cond.L.Lock()
+	defer q.cond.L.Unlock()
+	if q.shuttingDown {
+		return
+	}
+	if q.dirty.has(item) {
+		return
+	}
+
+	q.metrics.add(item)
+
+	q.dirty.insert(item)
+	if q.processing.has(item) {
+		return
+	}
+
+	q.queue = append(q.queue, item)
+	q.cond.Signal()
+}
+
+// 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 (q *Type) Len() int {
+	q.cond.L.Lock()
+	defer q.cond.L.Unlock()
+	return len(q.queue)
+}
+
+// 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 (q *Type) Get() (item interface{}, shutdown bool) {
+	q.cond.L.Lock()
+	defer q.cond.L.Unlock()
+	for len(q.queue) == 0 && !q.shuttingDown {
+		q.cond.Wait()
+	}
+	if len(q.queue) == 0 {
+		// We must be shutting down.
+		return nil, true
+	}
+
+	item, q.queue = q.queue[0], q.queue[1:]
+
+	q.metrics.get(item)
+
+	q.processing.insert(item)
+	q.dirty.delete(item)
+
+	return item, false
+}
+
+// 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 (q *Type) Done(item interface{}) {
+	q.cond.L.Lock()
+	defer q.cond.L.Unlock()
+
+	q.metrics.done(item)
+
+	q.processing.delete(item)
+	if q.dirty.has(item) {
+		q.queue = append(q.queue, item)
+		q.cond.Signal()
+	}
+}
+
+// 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 (q *Type) ShutDown() {
+	q.cond.L.Lock()
+	defer q.cond.L.Unlock()
+	q.shuttingDown = true
+	q.cond.Broadcast()
+}
+
+func (q *Type) ShuttingDown() bool {
+	q.cond.L.Lock()
+	defer q.cond.L.Unlock()
+
+	return q.shuttingDown
+}

vendor/k8s.io/client-go/util/workqueue/queue_test.go

@@ -0,0 +1,161 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+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_test
+
+import (
+	"sync"
+	"testing"
+	"time"
+
+	"k8s.io/client-go/util/workqueue"
+)
+
+func TestBasic(t *testing.T) {
+	// If something is seriously wrong this test will never complete.
+	q := workqueue.New()
+
+	// Start producers
+	const producers = 50
+	producerWG := sync.WaitGroup{}
+	producerWG.Add(producers)
+	for i := 0; i < producers; i++ {
+		go func(i int) {
+			defer producerWG.Done()
+			for j := 0; j < 50; j++ {
+				q.Add(i)
+				time.Sleep(time.Millisecond)
+			}
+		}(i)
+	}
+
+	// Start consumers
+	const consumers = 10
+	consumerWG := sync.WaitGroup{}
+	consumerWG.Add(consumers)
+	for i := 0; i < consumers; i++ {
+		go func(i int) {
+			defer consumerWG.Done()
+			for {
+				item, quit := q.Get()
+				if item == "added after shutdown!" {
+					t.Errorf("Got an item added after shutdown.")
+				}
+				if quit {
+					return
+				}
+				t.Logf("Worker %v: begin processing %v", i, item)
+				time.Sleep(3 * time.Millisecond)
+				t.Logf("Worker %v: done processing %v", i, item)
+				q.Done(item)
+			}
+		}(i)
+	}
+
+	producerWG.Wait()
+	q.ShutDown()
+	q.Add("added after shutdown!")
+	consumerWG.Wait()
+}
+
+func TestAddWhileProcessing(t *testing.T) {
+	q := workqueue.New()
+
+	// Start producers
+	const producers = 50
+	producerWG := sync.WaitGroup{}
+	producerWG.Add(producers)
+	for i := 0; i < producers; i++ {
+		go func(i int) {
+			defer producerWG.Done()
+			q.Add(i)
+		}(i)
+	}
+
+	// Start consumers
+	const consumers = 10
+	consumerWG := sync.WaitGroup{}
+	consumerWG.Add(consumers)
+	for i := 0; i < consumers; i++ {
+		go func(i int) {
+			defer consumerWG.Done()
+			// Every worker will re-add every item up to two times.
+			// This tests the dirty-while-processing case.
+			counters := map[interface{}]int{}
+			for {
+				item, quit := q.Get()
+				if quit {
+					return
+				}
+				counters[item]++
+				if counters[item] < 2 {
+					q.Add(item)
+				}
+				q.Done(item)
+			}
+		}(i)
+	}
+
+	producerWG.Wait()
+	q.ShutDown()
+	consumerWG.Wait()
+}
+
+func TestLen(t *testing.T) {
+	q := workqueue.New()
+	q.Add("foo")
+	if e, a := 1, q.Len(); e != a {
+		t.Errorf("Expected %v, got %v", e, a)
+	}
+	q.Add("bar")
+	if e, a := 2, q.Len(); e != a {
+		t.Errorf("Expected %v, got %v", e, a)
+	}
+	q.Add("foo") // should not increase the queue length.
+	if e, a := 2, q.Len(); e != a {
+		t.Errorf("Expected %v, got %v", e, a)
+	}
+}
+
+func TestReinsert(t *testing.T) {
+	q := workqueue.New()
+	q.Add("foo")
+
+	// Start processing
+	i, _ := q.Get()
+	if i != "foo" {
+		t.Errorf("Expected %v, got %v", "foo", i)
+	}
+
+	// Add it back while processing
+	q.Add(i)
+
+	// Finish it up
+	q.Done(i)
+
+	// It should be back on the queue
+	i, _ = q.Get()
+	if i != "foo" {
+		t.Errorf("Expected %v, got %v", "foo", i)
+	}
+
+	// Finish that one up
+	q.Done(i)
+
+	if a := q.Len(); a != 0 {
+		t.Errorf("Expected queue to be empty. Has %v items", a)
+	}
+}

vendor/k8s.io/client-go/util/workqueue/rate_limitting_queue.go

@@ -0,0 +1,69 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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 rate limits items being added to the queue.
+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,
+	}
+}
+
+func NewNamedRateLimitingQueue(rateLimiter RateLimiter, name string) RateLimitingInterface {
+	return &rateLimitingType{
+		DelayingInterface: NewNamedDelayingQueue(name),
+		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)
+}

vendor/k8s.io/client-go/util/workqueue/rate_limitting_queue_test.go

@@ -0,0 +1,75 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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
+
+import (
+	"testing"
+	"time"
+
+	"k8s.io/apimachinery/pkg/util/clock"
+)
+
+func TestRateLimitingQueue(t *testing.T) {
+	limiter := NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Second)
+	queue := NewRateLimitingQueue(limiter).(*rateLimitingType)
+	fakeClock := clock.NewFakeClock(time.Now())
+	delayingQueue := &delayingType{
+		Interface:       New(),
+		clock:           fakeClock,
+		heartbeat:       fakeClock.Tick(maxWait),
+		stopCh:          make(chan struct{}),
+		waitingForAddCh: make(chan *waitFor, 1000),
+		metrics:         newRetryMetrics(""),
+	}
+	queue.DelayingInterface = delayingQueue
+
+	queue.AddRateLimited("one")
+	waitEntry := <-delayingQueue.waitingForAddCh
+	if e, a := 1*time.Millisecond, waitEntry.readyAt.Sub(fakeClock.Now()); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	queue.AddRateLimited("one")
+	waitEntry = <-delayingQueue.waitingForAddCh
+	if e, a := 2*time.Millisecond, waitEntry.readyAt.Sub(fakeClock.Now()); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	if e, a := 2, queue.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	queue.AddRateLimited("two")
+	waitEntry = <-delayingQueue.waitingForAddCh
+	if e, a := 1*time.Millisecond, waitEntry.readyAt.Sub(fakeClock.Now()); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	queue.AddRateLimited("two")
+	waitEntry = <-delayingQueue.waitingForAddCh
+	if e, a := 2*time.Millisecond, waitEntry.readyAt.Sub(fakeClock.Now()); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+	queue.Forget("one")
+	if e, a := 0, queue.NumRequeues("one"); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+	queue.AddRateLimited("one")
+	waitEntry = <-delayingQueue.waitingForAddCh
+	if e, a := 1*time.Millisecond, waitEntry.readyAt.Sub(fakeClock.Now()); e != a {
+		t.Errorf("expected %v, got %v", e, a)
+	}
+
+}