mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-12-22 04:50:23 +00:00
359 lines
9.9 KiB
Go
359 lines
9.9 KiB
Go
/*
|
|
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 cache
|
|
|
|
import (
|
|
"errors"
|
|
"sync"
|
|
|
|
"k8s.io/apimachinery/pkg/util/sets"
|
|
)
|
|
|
|
// PopProcessFunc is passed to Pop() method of Queue interface.
|
|
// It is supposed to process the element popped from the queue.
|
|
type PopProcessFunc func(interface{}) error
|
|
|
|
// ErrRequeue may be returned by a PopProcessFunc to safely requeue
|
|
// the current item. The value of Err will be returned from Pop.
|
|
type ErrRequeue struct {
|
|
// Err is returned by the Pop function
|
|
Err error
|
|
}
|
|
|
|
var FIFOClosedError error = errors.New("DeltaFIFO: manipulating with closed queue")
|
|
|
|
func (e ErrRequeue) Error() string {
|
|
if e.Err == nil {
|
|
return "the popped item should be requeued without returning an error"
|
|
}
|
|
return e.Err.Error()
|
|
}
|
|
|
|
// Queue is exactly like a Store, but has a Pop() method too.
|
|
type Queue interface {
|
|
Store
|
|
|
|
// Pop blocks until it has something to process.
|
|
// It returns the object that was process and the result of processing.
|
|
// The PopProcessFunc may return an ErrRequeue{...} to indicate the item
|
|
// should be requeued before releasing the lock on the queue.
|
|
Pop(PopProcessFunc) (interface{}, error)
|
|
|
|
// AddIfNotPresent adds a value previously
|
|
// returned by Pop back into the queue as long
|
|
// as nothing else (presumably more recent)
|
|
// has since been added.
|
|
AddIfNotPresent(interface{}) error
|
|
|
|
// HasSynced returns true if the first batch of items has been popped
|
|
HasSynced() bool
|
|
|
|
// Close queue
|
|
Close()
|
|
}
|
|
|
|
// Helper function for popping from Queue.
|
|
// WARNING: Do NOT use this function in non-test code to avoid races
|
|
// unless you really really really really know what you are doing.
|
|
func Pop(queue Queue) interface{} {
|
|
var result interface{}
|
|
queue.Pop(func(obj interface{}) error {
|
|
result = obj
|
|
return nil
|
|
})
|
|
return result
|
|
}
|
|
|
|
// FIFO receives adds and updates from a Reflector, and puts them in a queue for
|
|
// FIFO order processing. If multiple adds/updates of a single item happen while
|
|
// an item is in the queue before it has been processed, it will only be
|
|
// processed once, and when it is processed, the most recent version will be
|
|
// processed. This can't be done with a channel.
|
|
//
|
|
// FIFO solves this use case:
|
|
// * You want to process every object (exactly) once.
|
|
// * You want to process the most recent version of the object when you process it.
|
|
// * You do not want to process deleted objects, they should be removed from the queue.
|
|
// * You do not want to periodically reprocess objects.
|
|
// Compare with DeltaFIFO for other use cases.
|
|
type FIFO struct {
|
|
lock sync.RWMutex
|
|
cond sync.Cond
|
|
// We depend on the property that items in the set are in the queue and vice versa.
|
|
items map[string]interface{}
|
|
queue []string
|
|
|
|
// populated is true if the first batch of items inserted by Replace() has been populated
|
|
// or Delete/Add/Update was called first.
|
|
populated bool
|
|
// initialPopulationCount is the number of items inserted by the first call of Replace()
|
|
initialPopulationCount int
|
|
|
|
// keyFunc is used to make the key used for queued item insertion and retrieval, and
|
|
// should be deterministic.
|
|
keyFunc KeyFunc
|
|
|
|
// Indication the queue is closed.
|
|
// Used to indicate a queue is closed so a control loop can exit when a queue is empty.
|
|
// Currently, not used to gate any of CRED operations.
|
|
closed bool
|
|
closedLock sync.Mutex
|
|
}
|
|
|
|
var (
|
|
_ = Queue(&FIFO{}) // FIFO is a Queue
|
|
)
|
|
|
|
// Close the queue.
|
|
func (f *FIFO) Close() {
|
|
f.closedLock.Lock()
|
|
defer f.closedLock.Unlock()
|
|
f.closed = true
|
|
f.cond.Broadcast()
|
|
}
|
|
|
|
// Return true if an Add/Update/Delete/AddIfNotPresent are called first,
|
|
// or an Update called first but the first batch of items inserted by Replace() has been popped
|
|
func (f *FIFO) HasSynced() bool {
|
|
f.lock.Lock()
|
|
defer f.lock.Unlock()
|
|
return f.populated && f.initialPopulationCount == 0
|
|
}
|
|
|
|
// Add inserts an item, and puts it in the queue. The item is only enqueued
|
|
// if it doesn't already exist in the set.
|
|
func (f *FIFO) Add(obj interface{}) error {
|
|
id, err := f.keyFunc(obj)
|
|
if err != nil {
|
|
return KeyError{obj, err}
|
|
}
|
|
f.lock.Lock()
|
|
defer f.lock.Unlock()
|
|
f.populated = true
|
|
if _, exists := f.items[id]; !exists {
|
|
f.queue = append(f.queue, id)
|
|
}
|
|
f.items[id] = obj
|
|
f.cond.Broadcast()
|
|
return nil
|
|
}
|
|
|
|
// AddIfNotPresent inserts an item, and puts it in the queue. If the item is already
|
|
// present in the set, it is neither enqueued nor added to the set.
|
|
//
|
|
// This is useful in a single producer/consumer scenario so that the consumer can
|
|
// safely retry items without contending with the producer and potentially enqueueing
|
|
// stale items.
|
|
func (f *FIFO) AddIfNotPresent(obj interface{}) error {
|
|
id, err := f.keyFunc(obj)
|
|
if err != nil {
|
|
return KeyError{obj, err}
|
|
}
|
|
f.lock.Lock()
|
|
defer f.lock.Unlock()
|
|
f.addIfNotPresent(id, obj)
|
|
return nil
|
|
}
|
|
|
|
// addIfNotPresent assumes the fifo lock is already held and adds the provided
|
|
// item to the queue under id if it does not already exist.
|
|
func (f *FIFO) addIfNotPresent(id string, obj interface{}) {
|
|
f.populated = true
|
|
if _, exists := f.items[id]; exists {
|
|
return
|
|
}
|
|
|
|
f.queue = append(f.queue, id)
|
|
f.items[id] = obj
|
|
f.cond.Broadcast()
|
|
}
|
|
|
|
// Update is the same as Add in this implementation.
|
|
func (f *FIFO) Update(obj interface{}) error {
|
|
return f.Add(obj)
|
|
}
|
|
|
|
// Delete removes an item. It doesn't add it to the queue, because
|
|
// this implementation assumes the consumer only cares about the objects,
|
|
// not the order in which they were created/added.
|
|
func (f *FIFO) Delete(obj interface{}) error {
|
|
id, err := f.keyFunc(obj)
|
|
if err != nil {
|
|
return KeyError{obj, err}
|
|
}
|
|
f.lock.Lock()
|
|
defer f.lock.Unlock()
|
|
f.populated = true
|
|
delete(f.items, id)
|
|
return err
|
|
}
|
|
|
|
// List returns a list of all the items.
|
|
func (f *FIFO) List() []interface{} {
|
|
f.lock.RLock()
|
|
defer f.lock.RUnlock()
|
|
list := make([]interface{}, 0, len(f.items))
|
|
for _, item := range f.items {
|
|
list = append(list, item)
|
|
}
|
|
return list
|
|
}
|
|
|
|
// ListKeys returns a list of all the keys of the objects currently
|
|
// in the FIFO.
|
|
func (f *FIFO) ListKeys() []string {
|
|
f.lock.RLock()
|
|
defer f.lock.RUnlock()
|
|
list := make([]string, 0, len(f.items))
|
|
for key := range f.items {
|
|
list = append(list, key)
|
|
}
|
|
return list
|
|
}
|
|
|
|
// Get returns the requested item, or sets exists=false.
|
|
func (f *FIFO) Get(obj interface{}) (item interface{}, exists bool, err error) {
|
|
key, err := f.keyFunc(obj)
|
|
if err != nil {
|
|
return nil, false, KeyError{obj, err}
|
|
}
|
|
return f.GetByKey(key)
|
|
}
|
|
|
|
// GetByKey returns the requested item, or sets exists=false.
|
|
func (f *FIFO) GetByKey(key string) (item interface{}, exists bool, err error) {
|
|
f.lock.RLock()
|
|
defer f.lock.RUnlock()
|
|
item, exists = f.items[key]
|
|
return item, exists, nil
|
|
}
|
|
|
|
// Checks if the queue is closed
|
|
func (f *FIFO) IsClosed() bool {
|
|
f.closedLock.Lock()
|
|
defer f.closedLock.Unlock()
|
|
if f.closed {
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
// Pop waits until an item is ready and processes it. If multiple items are
|
|
// ready, they are returned in the order in which they were added/updated.
|
|
// The item is removed from the queue (and the store) before it is processed,
|
|
// so if you don't successfully process it, it should be added back with
|
|
// AddIfNotPresent(). process function is called under lock, so it is safe
|
|
// update data structures in it that need to be in sync with the queue.
|
|
func (f *FIFO) Pop(process PopProcessFunc) (interface{}, error) {
|
|
f.lock.Lock()
|
|
defer f.lock.Unlock()
|
|
for {
|
|
for len(f.queue) == 0 {
|
|
// When the queue is empty, invocation of Pop() is blocked until new item is enqueued.
|
|
// When Close() is called, the f.closed is set and the condition is broadcasted.
|
|
// Which causes this loop to continue and return from the Pop().
|
|
if f.IsClosed() {
|
|
return nil, FIFOClosedError
|
|
}
|
|
|
|
f.cond.Wait()
|
|
}
|
|
id := f.queue[0]
|
|
f.queue = f.queue[1:]
|
|
if f.initialPopulationCount > 0 {
|
|
f.initialPopulationCount--
|
|
}
|
|
item, ok := f.items[id]
|
|
if !ok {
|
|
// Item may have been deleted subsequently.
|
|
continue
|
|
}
|
|
delete(f.items, id)
|
|
err := process(item)
|
|
if e, ok := err.(ErrRequeue); ok {
|
|
f.addIfNotPresent(id, item)
|
|
err = e.Err
|
|
}
|
|
return item, err
|
|
}
|
|
}
|
|
|
|
// Replace will delete the contents of 'f', using instead the given map.
|
|
// 'f' takes ownership of the map, you should not reference the map again
|
|
// after calling this function. f's queue is reset, too; upon return, it
|
|
// will contain the items in the map, in no particular order.
|
|
func (f *FIFO) Replace(list []interface{}, resourceVersion string) error {
|
|
items := map[string]interface{}{}
|
|
for _, item := range list {
|
|
key, err := f.keyFunc(item)
|
|
if err != nil {
|
|
return KeyError{item, err}
|
|
}
|
|
items[key] = item
|
|
}
|
|
|
|
f.lock.Lock()
|
|
defer f.lock.Unlock()
|
|
|
|
if !f.populated {
|
|
f.populated = true
|
|
f.initialPopulationCount = len(items)
|
|
}
|
|
|
|
f.items = items
|
|
f.queue = f.queue[:0]
|
|
for id := range items {
|
|
f.queue = append(f.queue, id)
|
|
}
|
|
if len(f.queue) > 0 {
|
|
f.cond.Broadcast()
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Resync will touch all objects to put them into the processing queue
|
|
func (f *FIFO) Resync() error {
|
|
f.lock.Lock()
|
|
defer f.lock.Unlock()
|
|
|
|
inQueue := sets.NewString()
|
|
for _, id := range f.queue {
|
|
inQueue.Insert(id)
|
|
}
|
|
for id := range f.items {
|
|
if !inQueue.Has(id) {
|
|
f.queue = append(f.queue, id)
|
|
}
|
|
}
|
|
if len(f.queue) > 0 {
|
|
f.cond.Broadcast()
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// NewFIFO returns a Store which can be used to queue up items to
|
|
// process.
|
|
func NewFIFO(keyFunc KeyFunc) *FIFO {
|
|
f := &FIFO{
|
|
items: map[string]interface{}{},
|
|
queue: []string{},
|
|
keyFunc: keyFunc,
|
|
}
|
|
f.cond.L = &f.lock
|
|
return f
|
|
}
|