| /* |
| * 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 aggregate |
| |
| import ( |
| "sync" |
| "time" |
| ) |
| |
| // TimeWindowCounter wrappers sliding window around a counter. |
| // |
| // It is concurrent-safe. |
| // When it works for calculating QPS, the counter's value means the number of requests in a pane. |
| type TimeWindowCounter struct { |
| window *slidingWindow |
| mux sync.RWMutex |
| } |
| |
| func NewTimeWindowCounter(paneCount int, timeWindowSeconds int64) *TimeWindowCounter { |
| return &TimeWindowCounter{ |
| window: newSlidingWindow(paneCount, timeWindowSeconds*1000), |
| } |
| } |
| |
| // Count returns the sum of all panes' value. |
| func (t *TimeWindowCounter) Count() float64 { |
| t.mux.RLock() |
| defer t.mux.RUnlock() |
| |
| total := float64(0) |
| for _, v := range t.window.values(time.Now().UnixMilli()) { |
| total += v.(*counter).value |
| } |
| return total |
| } |
| |
| // LivedSeconds returns the lived seconds of the sliding window. |
| func (t *TimeWindowCounter) LivedSeconds() int64 { |
| t.mux.RLock() |
| defer t.mux.RUnlock() |
| |
| windowLength := len(t.window.values(time.Now().UnixMilli())) |
| return int64(windowLength) * t.window.paneIntervalInMs / 1000 |
| } |
| |
| // Add adds a step to the counter. |
| func (t *TimeWindowCounter) Add(step float64) { |
| t.mux.Lock() |
| defer t.mux.Unlock() |
| |
| t.window.currentPane(time.Now().UnixMilli(), t.newEmptyValue).value.(*counter).add(step) |
| } |
| |
| // Inc increments the counter by 1. |
| func (t *TimeWindowCounter) Inc() { |
| t.Add(1) |
| } |
| |
| func (t *TimeWindowCounter) newEmptyValue() interface{} { |
| return &counter{0} |
| } |
| |
| type counter struct { |
| value float64 |
| } |
| |
| func (c *counter) add(v float64) { |
| c.value += v |
| } |