/
workqueue.go
139 lines (115 loc) · 3.48 KB
/
workqueue.go
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// Copyright 2016 IBM Corporation
//
// 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 kubernetes
import (
"sync"
"k8s.io/client-go/pkg/api/meta"
)
const (
workqueueSize = 1024
)
// AddFunc is the ResourceEventHandler function called when a watched Kubernetes API object is added.
type AddFunc func(obj interface{})
// UpdateFunc is the ResourceEventHandler function called when a watched Kubernetes API object is updated.
type UpdateFunc func(oldObj, newObj interface{})
// DeleteFunc is the ResourceEventHandler function called when a watched Kubernetes API object is deleted.
type DeleteFunc func(obj interface{})
// Workqueue enqueues and processes ResourceEventHandler callbacks from cache controllers.
type Workqueue struct {
workChan chan func()
stopChan chan struct{}
active bool
mutex sync.Mutex
}
// NewWorkqueue creates a new workqueue.
func NewWorkqueue() *Workqueue {
return &Workqueue{
workChan: make(chan func(), workqueueSize),
stopChan: make(chan struct{}),
}
}
// Start launches a worker goroutine to process events from the queue.
func (wq *Workqueue) Start() {
wq.mutex.Lock()
defer wq.mutex.Unlock()
if wq.active {
return
}
wq.active = true
go wq.work()
}
// Stop the worker goroutine from processing events from the queue.
func (wq *Workqueue) Stop() {
wq.mutex.Lock()
defer wq.mutex.Unlock()
if !wq.active {
return
}
wq.active = false
wq.stopChan <- struct{}{}
}
// EnqueueingAddFunc returns an AddFunc that enqueues the given AddFunc invocation.
func (wq *Workqueue) EnqueueingAddFunc(f AddFunc) AddFunc {
return func(obj interface{}) {
wq.enqueueFunc(func() {
f(obj)
})
}
}
// EnqueueingUpdateFunc returns an UpdateFunc that enqueues the given UpdateFunc invocation.
// The wrapping UpdateFunc drops events in which the resource version of the old object is
// the same as the resource version of the new object (e.g., in case of a full cache resync).
func (wq *Workqueue) EnqueueingUpdateFunc(f UpdateFunc) UpdateFunc {
return func(oldObj, newObj interface{}) {
oldMeta, err := meta.Accessor(oldObj)
if err != nil {
return
}
newMeta, err := meta.Accessor(newObj)
if err != nil {
return
}
// Drop update in case that resource version hasn't changed (e.g., on full resync)
if oldMeta.GetResourceVersion() == newMeta.GetResourceVersion() {
return
}
wq.enqueueFunc(func() {
f(oldObj, newObj)
})
}
}
// EnqueueingDeleteFunc returns an DeleteFunc that enqueues the given DeleteFunc invocation.
func (wq *Workqueue) EnqueueingDeleteFunc(f DeleteFunc) DeleteFunc {
return func(obj interface{}) {
wq.enqueueFunc(func() {
f(obj)
})
}
}
// enqueueFunc enqueues the given function for later execution by the worker goroutine
func (wq *Workqueue) enqueueFunc(f func()) {
wq.workChan <- f
}
// work loops and invokes any functions queued for execution.
// It is run by the worker goroutine.
func (wq *Workqueue) work() {
for {
select {
case f := <-wq.workChan:
f()
case <-wq.stopChan:
return
}
}
}