469 lines
14 KiB
Go
469 lines
14 KiB
Go
|
/*
|
||
|
|
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 storage
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"sort"
|
||
|
|
"strconv"
|
||
|
|
"sync"
|
||
|
|
"time"
|
||
|
|
|
||
|
|
"k8s.io/apimachinery/pkg/api/errors"
|
||
|
|
"k8s.io/apimachinery/pkg/api/meta"
|
||
|
|
"k8s.io/apimachinery/pkg/labels"
|
||
|
|
"k8s.io/apimachinery/pkg/runtime"
|
||
|
|
"k8s.io/apimachinery/pkg/watch"
|
||
|
|
"k8s.io/kubernetes/pkg/client/cache"
|
||
|
|
"k8s.io/kubernetes/pkg/fields"
|
||
|
|
"k8s.io/kubernetes/pkg/util"
|
||
|
|
"k8s.io/kubernetes/pkg/util/clock"
|
||
|
|
)
|
||
|
|
|
||
|
|
const (
|
||
|
|
// blockTimeout determines how long we're willing to block the request
|
||
|
|
// to wait for a given resource version to be propagated to cache,
|
||
|
|
// before terminating request and returning Timeout error with retry
|
||
|
|
// after suggestion.
|
||
|
|
blockTimeout = 3 * time.Second
|
||
|
|
)
|
||
|
|
|
||
|
|
// watchCacheEvent is a single "watch event" that is send to users of
|
||
|
|
// watchCache. Additionally to a typical "watch.Event" it contains
|
||
|
|
// the previous value of the object to enable proper filtering in the
|
||
|
|
// upper layers.
|
||
|
|
type watchCacheEvent struct {
|
||
|
|
Type watch.EventType
|
||
|
|
Object runtime.Object
|
||
|
|
ObjLabels labels.Set
|
||
|
|
ObjFields fields.Set
|
||
|
|
PrevObject runtime.Object
|
||
|
|
PrevObjLabels labels.Set
|
||
|
|
PrevObjFields fields.Set
|
||
|
|
Key string
|
||
|
|
ResourceVersion uint64
|
||
|
|
}
|
||
|
|
|
||
|
|
// Computing a key of an object is generally non-trivial (it performs
|
||
|
|
// e.g. validation underneath). To avoid computing it multiple times
|
||
|
|
// (to serve the event in different List/Watch requests), in the
|
||
|
|
// underlying store we are keeping pair (key, object).
|
||
|
|
type storeElement struct {
|
||
|
|
Key string
|
||
|
|
Object runtime.Object
|
||
|
|
}
|
||
|
|
|
||
|
|
func storeElementKey(obj interface{}) (string, error) {
|
||
|
|
elem, ok := obj.(*storeElement)
|
||
|
|
if !ok {
|
||
|
|
return "", fmt.Errorf("not a storeElement: %v", obj)
|
||
|
|
}
|
||
|
|
return elem.Key, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// watchCacheElement is a single "watch event" stored in a cache.
|
||
|
|
// It contains the resource version of the object and the object
|
||
|
|
// itself.
|
||
|
|
type watchCacheElement struct {
|
||
|
|
resourceVersion uint64
|
||
|
|
watchCacheEvent *watchCacheEvent
|
||
|
|
}
|
||
|
|
|
||
|
|
// watchCache implements a Store interface.
|
||
|
|
// However, it depends on the elements implementing runtime.Object interface.
|
||
|
|
//
|
||
|
|
// watchCache is a "sliding window" (with a limited capacity) of objects
|
||
|
|
// observed from a watch.
|
||
|
|
type watchCache struct {
|
||
|
|
sync.RWMutex
|
||
|
|
|
||
|
|
// Condition on which lists are waiting for the fresh enough
|
||
|
|
// resource version.
|
||
|
|
cond *sync.Cond
|
||
|
|
|
||
|
|
// Maximum size of history window.
|
||
|
|
capacity int
|
||
|
|
|
||
|
|
// keyFunc is used to get a key in the underlying storage for a given object.
|
||
|
|
keyFunc func(runtime.Object) (string, error)
|
||
|
|
|
||
|
|
// getAttrsFunc is used to get labels and fields of an object.
|
||
|
|
getAttrsFunc func(runtime.Object) (labels.Set, fields.Set, error)
|
||
|
|
|
||
|
|
// cache is used a cyclic buffer - its first element (with the smallest
|
||
|
|
// resourceVersion) is defined by startIndex, its last element is defined
|
||
|
|
// by endIndex (if cache is full it will be startIndex + capacity).
|
||
|
|
// Both startIndex and endIndex can be greater than buffer capacity -
|
||
|
|
// you should always apply modulo capacity to get an index in cache array.
|
||
|
|
cache []watchCacheElement
|
||
|
|
startIndex int
|
||
|
|
endIndex int
|
||
|
|
|
||
|
|
// store will effectively support LIST operation from the "end of cache
|
||
|
|
// history" i.e. from the moment just after the newest cached watched event.
|
||
|
|
// It is necessary to effectively allow clients to start watching at now.
|
||
|
|
// NOTE: We assume that <store> is thread-safe.
|
||
|
|
store cache.Store
|
||
|
|
|
||
|
|
// ResourceVersion up to which the watchCache is propagated.
|
||
|
|
resourceVersion uint64
|
||
|
|
|
||
|
|
// This handler is run at the end of every successful Replace() method.
|
||
|
|
onReplace func()
|
||
|
|
|
||
|
|
// This handler is run at the end of every Add/Update/Delete method
|
||
|
|
// and additionally gets the previous value of the object.
|
||
|
|
onEvent func(*watchCacheEvent)
|
||
|
|
|
||
|
|
// for testing timeouts.
|
||
|
|
clock clock.Clock
|
||
|
|
}
|
||
|
|
|
||
|
|
func newWatchCache(
|
||
|
|
capacity int,
|
||
|
|
keyFunc func(runtime.Object) (string, error),
|
||
|
|
getAttrsFunc func(runtime.Object) (labels.Set, fields.Set, error)) *watchCache {
|
||
|
|
wc := &watchCache{
|
||
|
|
capacity: capacity,
|
||
|
|
keyFunc: keyFunc,
|
||
|
|
getAttrsFunc: getAttrsFunc,
|
||
|
|
cache: make([]watchCacheElement, capacity),
|
||
|
|
startIndex: 0,
|
||
|
|
endIndex: 0,
|
||
|
|
store: cache.NewStore(storeElementKey),
|
||
|
|
resourceVersion: 0,
|
||
|
|
clock: clock.RealClock{},
|
||
|
|
}
|
||
|
|
wc.cond = sync.NewCond(wc.RLocker())
|
||
|
|
return wc
|
||
|
|
}
|
||
|
|
|
||
|
|
// Add takes runtime.Object as an argument.
|
||
|
|
func (w *watchCache) Add(obj interface{}) error {
|
||
|
|
object, resourceVersion, err := objectToVersionedRuntimeObject(obj)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
event := watch.Event{Type: watch.Added, Object: object}
|
||
|
|
|
||
|
|
f := func(elem *storeElement) error { return w.store.Add(elem) }
|
||
|
|
return w.processEvent(event, resourceVersion, f)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Update takes runtime.Object as an argument.
|
||
|
|
func (w *watchCache) Update(obj interface{}) error {
|
||
|
|
object, resourceVersion, err := objectToVersionedRuntimeObject(obj)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
event := watch.Event{Type: watch.Modified, Object: object}
|
||
|
|
|
||
|
|
f := func(elem *storeElement) error { return w.store.Update(elem) }
|
||
|
|
return w.processEvent(event, resourceVersion, f)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Delete takes runtime.Object as an argument.
|
||
|
|
func (w *watchCache) Delete(obj interface{}) error {
|
||
|
|
object, resourceVersion, err := objectToVersionedRuntimeObject(obj)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
event := watch.Event{Type: watch.Deleted, Object: object}
|
||
|
|
|
||
|
|
f := func(elem *storeElement) error { return w.store.Delete(elem) }
|
||
|
|
return w.processEvent(event, resourceVersion, f)
|
||
|
|
}
|
||
|
|
|
||
|
|
func objectToVersionedRuntimeObject(obj interface{}) (runtime.Object, uint64, error) {
|
||
|
|
object, ok := obj.(runtime.Object)
|
||
|
|
if !ok {
|
||
|
|
return nil, 0, fmt.Errorf("obj does not implement runtime.Object interface: %v", obj)
|
||
|
|
}
|
||
|
|
meta, err := meta.Accessor(object)
|
||
|
|
if err != nil {
|
||
|
|
return nil, 0, err
|
||
|
|
}
|
||
|
|
resourceVersion, err := parseResourceVersion(meta.GetResourceVersion())
|
||
|
|
if err != nil {
|
||
|
|
return nil, 0, err
|
||
|
|
}
|
||
|
|
return object, resourceVersion, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func parseResourceVersion(resourceVersion string) (uint64, error) {
|
||
|
|
if resourceVersion == "" {
|
||
|
|
return 0, nil
|
||
|
|
}
|
||
|
|
// Use bitsize being the size of int on the machine.
|
||
|
|
return strconv.ParseUint(resourceVersion, 10, 0)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (w *watchCache) processEvent(event watch.Event, resourceVersion uint64, updateFunc func(*storeElement) error) error {
|
||
|
|
key, err := w.keyFunc(event.Object)
|
||
|
|
if err != nil {
|
||
|
|
return fmt.Errorf("couldn't compute key: %v", err)
|
||
|
|
}
|
||
|
|
elem := &storeElement{Key: key, Object: event.Object}
|
||
|
|
|
||
|
|
// TODO: We should consider moving this lock below after the watchCacheEvent
|
||
|
|
// is created. In such situation, the only problematic scenario is Replace(
|
||
|
|
// happening after getting object from store and before acquiring a lock.
|
||
|
|
// Maybe introduce another lock for this purpose.
|
||
|
|
w.Lock()
|
||
|
|
defer w.Unlock()
|
||
|
|
previous, exists, err := w.store.Get(elem)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
objLabels, objFields, err := w.getAttrsFunc(event.Object)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
var prevObject runtime.Object
|
||
|
|
var prevObjLabels labels.Set
|
||
|
|
var prevObjFields fields.Set
|
||
|
|
if exists {
|
||
|
|
prevObject = previous.(*storeElement).Object
|
||
|
|
prevObjLabels, prevObjFields, err = w.getAttrsFunc(prevObject)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
}
|
||
|
|
watchCacheEvent := &watchCacheEvent{
|
||
|
|
Type: event.Type,
|
||
|
|
Object: event.Object,
|
||
|
|
ObjLabels: objLabels,
|
||
|
|
ObjFields: objFields,
|
||
|
|
PrevObject: prevObject,
|
||
|
|
PrevObjLabels: prevObjLabels,
|
||
|
|
PrevObjFields: prevObjFields,
|
||
|
|
Key: key,
|
||
|
|
ResourceVersion: resourceVersion,
|
||
|
|
}
|
||
|
|
if w.onEvent != nil {
|
||
|
|
w.onEvent(watchCacheEvent)
|
||
|
|
}
|
||
|
|
w.updateCache(resourceVersion, watchCacheEvent)
|
||
|
|
w.resourceVersion = resourceVersion
|
||
|
|
w.cond.Broadcast()
|
||
|
|
return updateFunc(elem)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Assumes that lock is already held for write.
|
||
|
|
func (w *watchCache) updateCache(resourceVersion uint64, event *watchCacheEvent) {
|
||
|
|
if w.endIndex == w.startIndex+w.capacity {
|
||
|
|
// Cache is full - remove the oldest element.
|
||
|
|
w.startIndex++
|
||
|
|
}
|
||
|
|
w.cache[w.endIndex%w.capacity] = watchCacheElement{resourceVersion, event}
|
||
|
|
w.endIndex++
|
||
|
|
}
|
||
|
|
|
||
|
|
// List returns list of pointers to <storeElement> objects.
|
||
|
|
func (w *watchCache) List() []interface{} {
|
||
|
|
return w.store.List()
|
||
|
|
}
|
||
|
|
|
||
|
|
// waitUntilFreshAndBlock waits until cache is at least as fresh as given <resourceVersion>.
|
||
|
|
// NOTE: This function acquired lock and doesn't release it.
|
||
|
|
// You HAVE TO explicitly call w.RUnlock() after this function.
|
||
|
|
func (w *watchCache) waitUntilFreshAndBlock(resourceVersion uint64, trace *util.Trace) error {
|
||
|
|
startTime := w.clock.Now()
|
||
|
|
go func() {
|
||
|
|
// Wake us up when the time limit has expired. The docs
|
||
|
|
// promise that time.After (well, NewTimer, which it calls)
|
||
|
|
// will wait *at least* the duration given. Since this go
|
||
|
|
// routine starts sometime after we record the start time, and
|
||
|
|
// it will wake up the loop below sometime after the broadcast,
|
||
|
|
// we don't need to worry about waking it up before the time
|
||
|
|
// has expired accidentally.
|
||
|
|
<-w.clock.After(blockTimeout)
|
||
|
|
w.cond.Broadcast()
|
||
|
|
}()
|
||
|
|
|
||
|
|
w.RLock()
|
||
|
|
if trace != nil {
|
||
|
|
trace.Step("watchCache locked acquired")
|
||
|
|
}
|
||
|
|
for w.resourceVersion < resourceVersion {
|
||
|
|
if w.clock.Since(startTime) >= blockTimeout {
|
||
|
|
// Timeout with retry after 1 second.
|
||
|
|
return errors.NewTimeoutError(fmt.Sprintf("Too large resource version: %v, current: %v", resourceVersion, w.resourceVersion), 1)
|
||
|
|
}
|
||
|
|
w.cond.Wait()
|
||
|
|
}
|
||
|
|
if trace != nil {
|
||
|
|
trace.Step("watchCache fresh enough")
|
||
|
|
}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// WaitUntilFreshAndList returns list of pointers to <storeElement> objects.
|
||
|
|
func (w *watchCache) WaitUntilFreshAndList(resourceVersion uint64, trace *util.Trace) ([]interface{}, uint64, error) {
|
||
|
|
err := w.waitUntilFreshAndBlock(resourceVersion, trace)
|
||
|
|
defer w.RUnlock()
|
||
|
|
if err != nil {
|
||
|
|
return nil, 0, err
|
||
|
|
}
|
||
|
|
return w.store.List(), w.resourceVersion, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// WaitUntilFreshAndGet returns a pointers to <storeElement> object.
|
||
|
|
func (w *watchCache) WaitUntilFreshAndGet(resourceVersion uint64, key string, trace *util.Trace) (interface{}, bool, uint64, error) {
|
||
|
|
err := w.waitUntilFreshAndBlock(resourceVersion, trace)
|
||
|
|
defer w.RUnlock()
|
||
|
|
if err != nil {
|
||
|
|
return nil, false, 0, err
|
||
|
|
}
|
||
|
|
value, exists, err := w.store.GetByKey(key)
|
||
|
|
return value, exists, w.resourceVersion, err
|
||
|
|
}
|
||
|
|
|
||
|
|
func (w *watchCache) ListKeys() []string {
|
||
|
|
return w.store.ListKeys()
|
||
|
|
}
|
||
|
|
|
||
|
|
// Get takes runtime.Object as a parameter. However, it returns
|
||
|
|
// pointer to <storeElement>.
|
||
|
|
func (w *watchCache) Get(obj interface{}) (interface{}, bool, error) {
|
||
|
|
object, ok := obj.(runtime.Object)
|
||
|
|
if !ok {
|
||
|
|
return nil, false, fmt.Errorf("obj does not implement runtime.Object interface: %v", obj)
|
||
|
|
}
|
||
|
|
key, err := w.keyFunc(object)
|
||
|
|
if err != nil {
|
||
|
|
return nil, false, fmt.Errorf("couldn't compute key: %v", err)
|
||
|
|
}
|
||
|
|
|
||
|
|
return w.store.Get(&storeElement{Key: key, Object: object})
|
||
|
|
}
|
||
|
|
|
||
|
|
// GetByKey returns pointer to <storeElement>.
|
||
|
|
func (w *watchCache) GetByKey(key string) (interface{}, bool, error) {
|
||
|
|
return w.store.GetByKey(key)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Replace takes slice of runtime.Object as a paramater.
|
||
|
|
func (w *watchCache) Replace(objs []interface{}, resourceVersion string) error {
|
||
|
|
version, err := parseResourceVersion(resourceVersion)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
toReplace := make([]interface{}, 0, len(objs))
|
||
|
|
for _, obj := range objs {
|
||
|
|
object, ok := obj.(runtime.Object)
|
||
|
|
if !ok {
|
||
|
|
return fmt.Errorf("didn't get runtime.Object for replace: %#v", obj)
|
||
|
|
}
|
||
|
|
key, err := w.keyFunc(object)
|
||
|
|
if err != nil {
|
||
|
|
return fmt.Errorf("couldn't compute key: %v", err)
|
||
|
|
}
|
||
|
|
toReplace = append(toReplace, &storeElement{Key: key, Object: object})
|
||
|
|
}
|
||
|
|
|
||
|
|
w.Lock()
|
||
|
|
defer w.Unlock()
|
||
|
|
|
||
|
|
w.startIndex = 0
|
||
|
|
w.endIndex = 0
|
||
|
|
if err := w.store.Replace(toReplace, resourceVersion); err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
w.resourceVersion = version
|
||
|
|
if w.onReplace != nil {
|
||
|
|
w.onReplace()
|
||
|
|
}
|
||
|
|
w.cond.Broadcast()
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (w *watchCache) SetOnReplace(onReplace func()) {
|
||
|
|
w.Lock()
|
||
|
|
defer w.Unlock()
|
||
|
|
w.onReplace = onReplace
|
||
|
|
}
|
||
|
|
|
||
|
|
func (w *watchCache) SetOnEvent(onEvent func(*watchCacheEvent)) {
|
||
|
|
w.Lock()
|
||
|
|
defer w.Unlock()
|
||
|
|
w.onEvent = onEvent
|
||
|
|
}
|
||
|
|
|
||
|
|
func (w *watchCache) GetAllEventsSinceThreadUnsafe(resourceVersion uint64) ([]*watchCacheEvent, error) {
|
||
|
|
size := w.endIndex - w.startIndex
|
||
|
|
oldest := w.resourceVersion
|
||
|
|
if size > 0 {
|
||
|
|
oldest = w.cache[w.startIndex%w.capacity].resourceVersion
|
||
|
|
}
|
||
|
|
if resourceVersion == 0 {
|
||
|
|
// resourceVersion = 0 means that we don't require any specific starting point
|
||
|
|
// and we would like to start watching from ~now.
|
||
|
|
// However, to keep backward compatibility, we additionally need to return the
|
||
|
|
// current state and only then start watching from that point.
|
||
|
|
//
|
||
|
|
// TODO: In v2 api, we should stop returning the current state - #13969.
|
||
|
|
allItems := w.store.List()
|
||
|
|
result := make([]*watchCacheEvent, len(allItems))
|
||
|
|
for i, item := range allItems {
|
||
|
|
elem, ok := item.(*storeElement)
|
||
|
|
if !ok {
|
||
|
|
return nil, fmt.Errorf("not a storeElement: %v", elem)
|
||
|
|
}
|
||
|
|
objLabels, objFields, err := w.getAttrsFunc(elem.Object)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
result[i] = &watchCacheEvent{
|
||
|
|
Type: watch.Added,
|
||
|
|
Object: elem.Object,
|
||
|
|
ObjLabels: objLabels,
|
||
|
|
ObjFields: objFields,
|
||
|
|
Key: elem.Key,
|
||
|
|
ResourceVersion: w.resourceVersion,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return result, nil
|
||
|
|
}
|
||
|
|
if resourceVersion < oldest-1 {
|
||
|
|
return nil, errors.NewGone(fmt.Sprintf("too old resource version: %d (%d)", resourceVersion, oldest-1))
|
||
|
|
}
|
||
|
|
|
||
|
|
// Binary search the smallest index at which resourceVersion is greater than the given one.
|
||
|
|
f := func(i int) bool {
|
||
|
|
return w.cache[(w.startIndex+i)%w.capacity].resourceVersion > resourceVersion
|
||
|
|
}
|
||
|
|
first := sort.Search(size, f)
|
||
|
|
result := make([]*watchCacheEvent, size-first)
|
||
|
|
for i := 0; i < size-first; i++ {
|
||
|
|
result[i] = w.cache[(w.startIndex+first+i)%w.capacity].watchCacheEvent
|
||
|
|
}
|
||
|
|
return result, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func (w *watchCache) GetAllEventsSince(resourceVersion uint64) ([]*watchCacheEvent, error) {
|
||
|
|
w.RLock()
|
||
|
|
defer w.RUnlock()
|
||
|
|
return w.GetAllEventsSinceThreadUnsafe(resourceVersion)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (w *watchCache) Resync() error {
|
||
|
|
// Nothing to do
|
||
|
|
return nil
|
||
|
|
}
|