knative.dev/pkg@v0.0.0-20260602142205-ac97e43f6622/configmap/manual_watcher.go (about)

     1  /*
     2  Copyright 2018 The Knative Authors
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package configmap
    18  
    19  import (
    20  	"sync"
    21  
    22  	corev1 "k8s.io/api/core/v1"
    23  )
    24  
    25  // ManualWatcher will notify Observers when a ConfigMap is manually reported as changed
    26  type ManualWatcher struct {
    27  	Namespace string
    28  
    29  	// Guards observers
    30  	sync.RWMutex
    31  	observers map[string][]Observer
    32  }
    33  
    34  var _ Watcher = (*ManualWatcher)(nil)
    35  
    36  // Watch implements Watcher
    37  func (w *ManualWatcher) Watch(name string, o ...Observer) {
    38  	w.Lock()
    39  	defer w.Unlock()
    40  
    41  	if w.observers == nil {
    42  		w.observers = make(map[string][]Observer, 1)
    43  	}
    44  	w.observers[name] = append(w.observers[name], o...)
    45  }
    46  
    47  // ForEach implements Watcher
    48  func (w *ManualWatcher) ForEach(f func(string, []Observer) error) error {
    49  	for k, v := range w.observers {
    50  		if err := f(k, v); err != nil {
    51  			return err
    52  		}
    53  	}
    54  	return nil
    55  }
    56  
    57  // Start implements Watcher
    58  func (w *ManualWatcher) Start(<-chan struct{}) error {
    59  	return nil
    60  }
    61  
    62  // OnChange invokes the callbacks of all observers of the given ConfigMap.
    63  func (w *ManualWatcher) OnChange(configMap *corev1.ConfigMap) {
    64  	if configMap.Namespace != w.Namespace {
    65  		return
    66  	}
    67  	// Within our namespace, take the lock and see if there are any registered observers.
    68  	w.RLock()
    69  	defer w.RUnlock()
    70  	// Iterate over the observers and invoke their callbacks.
    71  	for _, o := range w.observers[configMap.Name] {
    72  		o(configMap)
    73  	}
    74  }