| /* |
| * 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 tps |
| |
| import ( |
| "container/list" |
| "sync" |
| "time" |
| ) |
| |
| import ( |
| "github.com/apache/dubbo-go/common/extension" |
| "github.com/apache/dubbo-go/filter" |
| ) |
| |
| func init() { |
| extension.SetTpsLimitStrategy("slidingWindow", &slidingWindowStrategyCreator{}) |
| } |
| |
| /** |
| * it's thread-safe. |
| * "UserProvider": |
| * registry: "hangzhouzk" |
| * protocol : "dubbo" |
| * interface : "com.ikurento.user.UserProvider" |
| * ... # other configuration |
| * tps.limiter: "method-service" # the name of limiter |
| * tps.limit.strategy: "slidingWindow" # service-level |
| * methods: |
| * - name: "GetUser" |
| * tps.interval: 3000 |
| * tps.limit.strategy: "slidingWindow" # method-level |
| */ |
| type SlidingWindowTpsLimitStrategyImpl struct { |
| rate int |
| interval int64 |
| mutex *sync.Mutex |
| queue *list.List |
| } |
| |
| // IsAllowable ... |
| func (impl *SlidingWindowTpsLimitStrategyImpl) IsAllowable() bool { |
| impl.mutex.Lock() |
| defer impl.mutex.Unlock() |
| // quick path |
| size := impl.queue.Len() |
| current := time.Now().UnixNano() |
| if size < impl.rate { |
| impl.queue.PushBack(current) |
| return true |
| } |
| |
| // slow path |
| boundary := current - impl.interval |
| |
| timestamp := impl.queue.Front() |
| // remove the element that out of the window |
| for timestamp != nil && timestamp.Value.(int64) < boundary { |
| impl.queue.Remove(timestamp) |
| timestamp = impl.queue.Front() |
| } |
| if impl.queue.Len() < impl.rate { |
| impl.queue.PushBack(current) |
| return true |
| } |
| return false |
| } |
| |
| type slidingWindowStrategyCreator struct{} |
| |
| func (creator *slidingWindowStrategyCreator) Create(rate int, interval int) filter.TpsLimitStrategy { |
| return &SlidingWindowTpsLimitStrategyImpl{ |
| rate: rate, |
| interval: int64(interval) * int64(time.Millisecond), |
| mutex: &sync.Mutex{}, |
| queue: list.New(), |
| } |
| } |