content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * Licensed 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 com.alibaba.nacos.client.config.impl;
  
  import com.alibaba.nacos.client.utils.LogUtils;
  import com.google.common.cache.Cache;
  import com.google.common.cache.CacheBuilder;
  import com.google.common.util.concurrent.RateLimiter;
  import org.slf4j.Logger;
  
  import java.util.concurrent.Callable;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.TimeUnit;
  
  /**
   * Limiter
   *
   * @author Nacos
   */
  public class Limiter {
  
      private static final Logger LOGGER = LogUtils.logger(Limiter.class);
  
      private static final int CAPACITY_SIZE = 1000;
      private static final int LIMIT_TIME = 1000;
      private static Cache<String, RateLimiter> cache = CacheBuilder.newBuilder()
          .initialCapacity(CAPACITY_SIZE).expireAfterAccess(1, TimeUnit.MINUTES)
          .build();
  
      /**
       * qps 5
       */
      private static double limit = 5;
  
      static {
          try {
              String limitTimeStr = System
                  .getProperty("limitTime", String.valueOf(limit));
              limit = Double.parseDouble(limitTimeStr);
              LOGGER.info("limitTime:{}", limit);
          } catch (Exception e) {
              LOGGER.error("init limitTime fail", e);
          }
      }
  
      public static boolean isLimit(String accessKeyID) {
          RateLimiter rateLimiter = null;
          try {
              rateLimiter = cache.get(accessKeyID, new Callable<RateLimiter>() {
                  @Override
                  public RateLimiter call() throws Exception {
                      return RateLimiter.create(limit);
                  }
              });
          } catch (ExecutionException e) {
              LOGGER.error("create limit fail", e);
          }
          if (rateLimiter != null && !rateLimiter.tryAcquire(LIMIT_TIME, TimeUnit.MILLISECONDS)) {
              LOGGER.error("access_key_id:{} limited", accessKeyID);
              return true;
          }
          return false;
      }
  
  }
  