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bus.go
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bus.go
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 metrics
import (
"sync"
)
// eventListener is a struct that encapsulates the listener map and provides thread-safe access to it.
type eventListener struct {
mu sync.RWMutex
listener map[string]chan MetricsEvent
}
var listener = &eventListener{
listener: make(map[string]chan MetricsEvent),
}
// Publish publishes an event to all subscribers of the same type.
func Publish(event MetricsEvent) {
listener.mu.RLock()
defer listener.mu.RUnlock()
if ch, ok := listener.listener[event.Type()]; ok {
select {
case ch <- event:
default:
// If the channel is full, drop the event to avoid blocking.
}
}
}
// Subscribe subscribes to events of the given type.
func Subscribe(typ string, ch chan MetricsEvent) {
listener.mu.Lock()
defer listener.mu.Unlock()
listener.listener[typ] = ch
}
// Unsubscribe unsubscribes from events of the given type.
func Unsubscribe(typ string) {
listener.mu.Lock()
defer listener.mu.Unlock()
if ch, ok := listener.listener[typ]; ok {
close(ch)
delete(listener.listener, typ)
}
}