| /* |
| * 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) |
| } |
| } |