| /* |
| * 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 org.apache.servicecomb.qps.strategy; |
| |
| import java.util.concurrent.atomic.AtomicLong; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| public class FixedWindowStrategy extends AbstractQpsStrategy { |
| |
| private static final Logger LOGGER = LoggerFactory.getLogger(FixedWindowStrategy.class); |
| |
| // Interval begin time |
| private volatile long msCycleBegin; |
| |
| // Request count between Interval begin and now in one interval |
| private final AtomicLong requestCount = new AtomicLong(); |
| |
| // request count before an interval |
| private volatile long lastRequestCount = 1; |
| |
| private static final int CYCLE_LENGTH = 1000; |
| |
| private static final String STRATEGY_NAME = "FixedWindow"; |
| |
| // return true means new request need to be rejected |
| public boolean isLimitNewRequest() { |
| if (this.getQpsLimit() == null) { |
| throw new IllegalStateException("should not happen"); |
| } |
| long newCount = requestCount.incrementAndGet(); |
| long msNow = System.currentTimeMillis(); |
| //Time jump cause the new request injected |
| if (msNow - msCycleBegin > CYCLE_LENGTH || msNow < msCycleBegin) { |
| //no need worry about concurrency problem |
| lastRequestCount = newCount; |
| msCycleBegin = msNow; |
| } |
| |
| // Configuration update and use is at the situation of multi-threaded concurrency |
| // It is possible that operation level updated to null,but schema level or microservice level does not updated |
| boolean isLimitRequest = newCount - lastRequestCount >= this.getQpsLimit(); |
| if (isLimitRequest){ |
| LOGGER.warn("qps flowcontrol open, qpsLimit is {} and tps is {}", this.getQpsLimit(), newCount - lastRequestCount + 1); |
| } |
| return isLimitRequest; |
| } |
| |
| @Override |
| public String name() { |
| return STRATEGY_NAME; |
| } |
| } |