| /* |
| * 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 events |
| |
| import ( |
| "sync" |
| ) |
| |
| import ( |
| "github.com/apache/dubbo-kubernetes/pkg/core" |
| ) |
| |
| var log = core.Log.WithName("eventbus") |
| |
| type subscriber struct { |
| ch chan Event |
| predicates []Predicate |
| } |
| |
| func NewEventBus(bufferSize uint) (EventBus, error) { |
| return &eventBus{ |
| subscribers: map[string]subscriber{}, |
| bufferSize: bufferSize, |
| }, nil |
| } |
| |
| type eventBus struct { |
| mtx sync.RWMutex |
| subscribers map[string]subscriber |
| bufferSize uint |
| } |
| |
| // Subscribe subscribes to a stream of events given Predicates |
| // Predicate should not block on I/O, otherwise the whole event bus can block. |
| // All predicates must pass for the event to enqueued. |
| func (b *eventBus) Subscribe(predicates ...Predicate) Listener { |
| id := core.NewUUID() |
| b.mtx.Lock() |
| defer b.mtx.Unlock() |
| |
| events := make(chan Event, b.bufferSize) |
| b.subscribers[id] = subscriber{ |
| ch: events, |
| predicates: predicates, |
| } |
| return &reader{ |
| events: events, |
| close: func() { |
| b.mtx.Lock() |
| defer b.mtx.Unlock() |
| delete(b.subscribers, id) |
| }, |
| } |
| } |
| |
| func (b *eventBus) Send(event Event) { |
| b.mtx.RLock() |
| defer b.mtx.RUnlock() |
| for _, sub := range b.subscribers { |
| matched := true |
| for _, predicate := range sub.predicates { |
| if !predicate(event) { |
| matched = false |
| } |
| } |
| if matched { |
| select { |
| case sub.ch <- event: |
| default: |
| log.Info("[WARNING] event is not sent because the channel is full. Ignoring event. Consider increasing buffer size using dubbo_EVENT_BUS_BUFFER_SIZE", |
| "bufferSize", b.bufferSize, |
| "event", event, |
| ) |
| } |
| } |
| } |
| } |
| |
| type reader struct { |
| events chan Event |
| close func() |
| } |
| |
| func (k *reader) Recv() <-chan Event { |
| return k.events |
| } |
| |
| func (k *reader) Close() { |
| k.close() |
| } |