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.csp.sentinel.dashboard.repository.metric;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.stream.Collectors;
  
  import com.alibaba.csp.sentinel.dashboard.datasource.entity.MetricEntity;
  import com.alibaba.csp.sentinel.util.StringUtil;
  
  import com.googlecode.concurrentlinkedhashmap.ConcurrentLinkedHashMap;
  import org.springframework.stereotype.Component;
  
  /**
   * Caches metrics data in a period of time in memory.
   *
   * @author Carpenter Lee
   * @author Eric Zhao
   */
  @Component
  public class InMemoryMetricsRepository implements MetricsRepository<MetricEntity> {
  
      private static final long MAX_METRIC_LIVE_TIME_MS = 1000 * 60 * 5;
  
      /**
       * {@code app -> resource -> timestamp -> metric}
       */
      private Map<String, Map<String, ConcurrentLinkedHashMap<Long, MetricEntity>>> allMetrics = new ConcurrentHashMap<>();
  
  
  
      @Override
      public synchronized void save(MetricEntity entity) {
          if (entity == null || StringUtil.isBlank(entity.getApp())) {
              return;
          }
          allMetrics.computeIfAbsent(entity.getApp(), e -> new ConcurrentHashMap<>(16))
              .computeIfAbsent(entity.getResource(), e -> new ConcurrentLinkedHashMap.Builder<Long, MetricEntity>()
                  .maximumWeightedCapacity(MAX_METRIC_LIVE_TIME_MS).weigher((key, value) -> {
                      // Metric older than {@link #MAX_METRIC_LIVE_TIME_MS} will be removed.
                      int weight = (int)(System.currentTimeMillis() - key);
                      // weight must be a number greater than or equal to one
                      return Math.max(weight, 1);
                  }).build()).put(entity.getTimestamp().getTime(), entity);
      }
  
      @Override
      public synchronized void saveAll(Iterable<MetricEntity> metrics) {
          if (metrics == null) {
              return;
          }
          metrics.forEach(this::save);
      }
  
      @Override
      public synchronized List<MetricEntity> queryByAppAndResourceBetween(String app, String resource,
                                                                          long startTime, long endTime) {
          List<MetricEntity> results = new ArrayList<>();
          if (StringUtil.isBlank(app)) {
              return results;
          }
          Map<String, ConcurrentLinkedHashMap<Long, MetricEntity>> resourceMap = allMetrics.get(app);
          if (resourceMap == null) {
              return results;
          }
          ConcurrentLinkedHashMap<Long, MetricEntity> metricsMap = resourceMap.get(resource);
          if (metricsMap == null) {
              return results;
          }
          for (Entry<Long, MetricEntity> entry : metricsMap.entrySet()) {
              if (entry.getKey() >= startTime && entry.getKey() <= endTime) {
                  results.add(entry.getValue());
              }
          }
          return results;
      }
  
      @Override
      public List<String> listResourcesOfApp(String app) {
          List<String> results = new ArrayList<>();
          if (StringUtil.isBlank(app)) {
              return results;
          }
          // resource -> timestamp -> metric
          Map<String, ConcurrentLinkedHashMap<Long, MetricEntity>> resourceMap = allMetrics.get(app);
          if (resourceMap == null) {
              return results;
          }
          final long minTimeMs = System.currentTimeMillis() - 1000 * 60;
          Map<String, MetricEntity> resourceCount = new ConcurrentHashMap<>(32);
  
          for (Entry<String, ConcurrentLinkedHashMap<Long, MetricEntity>> resourceMetrics : resourceMap.entrySet()) {
              for (Entry<Long, MetricEntity> metrics : resourceMetrics.getValue().entrySet()) {
                  if (metrics.getKey() < minTimeMs) {
                      continue;
                  }
                  MetricEntity newEntity = metrics.getValue();
                  if (resourceCount.containsKey(resourceMetrics.getKey())) {
                      MetricEntity oldEntity = resourceCount.get(resourceMetrics.getKey());
                      oldEntity.addPassQps(newEntity.getPassQps());
                      oldEntity.addRtAndSuccessQps(newEntity.getRt(), newEntity.getSuccessQps());
                      oldEntity.addBlockQps(newEntity.getBlockQps());
                      oldEntity.addExceptionQps(newEntity.getExceptionQps());
                      oldEntity.addCount(1);
                  } else {
                      resourceCount.put(resourceMetrics.getKey(), MetricEntity.copyOf(newEntity));
                  }
              }
          }
          // Order by last minute b_qps DESC.
          return resourceCount.entrySet()
              .stream()
              .sorted((o1, o2) -> {
                  MetricEntity e1 = o1.getValue();
                  MetricEntity e2 = o2.getValue();
                  int t = e2.getBlockQps().compareTo(e1.getBlockQps());
                  if (t != 0) {
                      return t;
                  }
                  return e2.getPassQps().compareTo(e1.getPassQps());
              })
              .map(Entry::getKey)
              .collect(Collectors.toList());
      }
  }
  