/**
    * 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.hadoop.hbase.regionserver;
  
  import java.util.Collection;
  import java.util.List;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.CompatibilitySingletonFactory;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.HDFSBlocksDistribution;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.io.hfile.BlockCache;
  import org.apache.hadoop.hbase.io.hfile.CacheConfig;
  import org.apache.hadoop.hbase.io.hfile.CacheStats;
  import org.apache.hadoop.hbase.wal.BoundedRegionGroupingProvider;
  import org.apache.hadoop.hbase.wal.DefaultWALProvider;
  import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
  import org.apache.hadoop.metrics2.MetricsExecutor;
  
  /**
   * Impl for exposing HRegionServer Information through Hadoop's metrics 2 system.
   */
  @InterfaceAudience.Private
  class MetricsRegionServerWrapperImpl
      implements MetricsRegionServerWrapper {
  
    public static final Log LOG = LogFactory.getLog(MetricsRegionServerWrapperImpl.class);
  
    private final HRegionServer regionServer;
  
    private BlockCache blockCache;
  
    private volatile long numStores = 0;
    private volatile long numWALFiles = 0;
    private volatile long walFileSize = 0;
    private volatile long numStoreFiles = 0;
    private volatile long memstoreSize = 0;
    private volatile long storeFileSize = 0;
    private volatile double requestsPerSecond = 0.0;
    private volatile long readRequestsCount = 0;
    private volatile long writeRequestsCount = 0;
    private volatile long checkAndMutateChecksFailed = 0;
    private volatile long checkAndMutateChecksPassed = 0;
    private volatile long storefileIndexSize = 0;
    private volatile long totalStaticIndexSize = 0;
    private volatile long totalStaticBloomSize = 0;
    private volatile long numMutationsWithoutWAL = 0;
    private volatile long dataInMemoryWithoutWAL = 0;
    private volatile int percentFileLocal = 0;
    private volatile int percentFileLocalSecondaryRegions = 0;
    private volatile long flushedCellsCount = 0;
    private volatile long compactedCellsCount = 0;
    private volatile long majorCompactedCellsCount = 0;
    private volatile long flushedCellsSize = 0;
    private volatile long compactedCellsSize = 0;
    private volatile long majorCompactedCellsSize = 0;
    private volatile long blockedRequestsCount = 0L;
  
    private CacheStats cacheStats;
    private ScheduledExecutorService executor;
    private Runnable runnable;
    private long period;
  
    public MetricsRegionServerWrapperImpl(final HRegionServer regionServer) {
      this.regionServer = regionServer;
      initBlockCache();
  
      this.period =
          regionServer.conf.getLong(HConstants.REGIONSERVER_METRICS_PERIOD,
            HConstants.DEFAULT_REGIONSERVER_METRICS_PERIOD);
  
      this.executor = CompatibilitySingletonFactory.getInstance(MetricsExecutor.class).getExecutor();
      this.runnable = new RegionServerMetricsWrapperRunnable();
      this.executor.scheduleWithFixedDelay(this.runnable, this.period, this.period,
        TimeUnit.MILLISECONDS);
  
     if (LOG.isInfoEnabled()) {
       LOG.info("Computing regionserver metrics every " + this.period + " milliseconds");
     }
   }
 
   /**
    * It's possible that due to threading the block cache could not be initialized
    * yet (testing multiple region servers in one jvm).  So we need to try and initialize
    * the blockCache and cacheStats reference multiple times until we succeed.
    */
   private synchronized  void initBlockCache() {
     CacheConfig cacheConfig = this.regionServer.cacheConfig;
     if (cacheConfig != null && this.blockCache == null) {
       this.blockCache = cacheConfig.getBlockCache();
     }
 
     if (this.blockCache != null && this.cacheStats == null) {
       this.cacheStats = blockCache.getStats();
     }
   }
 
   @Override
   public String getClusterId() {
     return regionServer.getClusterId();
   }
 
   @Override
   public long getStartCode() {
     return regionServer.getStartcode();
   }
 
   @Override
   public String getZookeeperQuorum() {
     ZooKeeperWatcher zk = regionServer.getZooKeeper();
     if (zk == null) {
       return "";
     }
     return zk.getQuorum();
   }
 
   @Override
   public String getCoprocessors() {
     String[] coprocessors = regionServer.getRegionServerCoprocessors();
     if (coprocessors == null || coprocessors.length == 0) {
       return "";
     }
     return StringUtils.join(coprocessors, ", ");
   }
 
   @Override
   public String getServerName() {
     ServerName serverName = regionServer.getServerName();
     if (serverName == null) {
       return "";
     }
     return serverName.getServerName();
   }
 
   @Override
   public long getNumOnlineRegions() {
     Collection<Region> onlineRegionsLocalContext = regionServer.getOnlineRegionsLocalContext();
     if (onlineRegionsLocalContext == null) {
       return 0;
     }
     return onlineRegionsLocalContext.size();
   }
 
   @Override
   public long getTotalRequestCount() {
     return regionServer.rpcServices.requestCount.get();
   }
 
   @Override
   public int getSplitQueueSize() {
     if (this.regionServer.compactSplitThread == null) {
       return 0;
     }
     return this.regionServer.compactSplitThread.getSplitQueueSize();
   }
 
   @Override
   public int getCompactionQueueSize() {
     //The thread could be zero.  if so assume there is no queue.
     if (this.regionServer.compactSplitThread == null) {
       return 0;
     }
     return this.regionServer.compactSplitThread.getCompactionQueueSize();
   }
 
   @Override
   public int getSmallCompactionQueueSize() {
     //The thread could be zero.  if so assume there is no queue.
     if (this.regionServer.compactSplitThread == null) {
       return 0;
     }
     return this.regionServer.compactSplitThread.getSmallCompactionQueueSize();
   }
 
   @Override
   public int getLargeCompactionQueueSize() {
     //The thread could be zero.  if so assume there is no queue.
     if (this.regionServer.compactSplitThread == null) {
       return 0;
     }
     return this.regionServer.compactSplitThread.getLargeCompactionQueueSize();
   }
 
   @Override
   public int getFlushQueueSize() {
     //If there is no flusher there should be no queue.
     if (this.regionServer.cacheFlusher == null) {
       return 0;
     }
     return this.regionServer.cacheFlusher.getFlushQueueSize();
   }
 
   @Override
   public long getBlockCacheCount() {
     if (this.blockCache == null) {
       return 0;
     }
     return this.blockCache.getBlockCount();
   }
 
   @Override
   public long getBlockCacheSize() {
     if (this.blockCache == null) {
       return 0;
     }
     return this.blockCache.getCurrentSize();
   }
 
   @Override
   public long getBlockCacheFreeSize() {
     if (this.blockCache == null) {
       return 0;
     }
     return this.blockCache.getFreeSize();
   }
 
   @Override
   public long getBlockCacheHitCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getHitCount();
   }
 
   @Override
   public long getBlockCacheMissCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getMissCount();
   }
 
   @Override
   public long getBlockCacheEvictedCount() {
     if (this.cacheStats == null) {
       return 0;
     }
     return this.cacheStats.getEvictedCount();
   }
 
   @Override
   public double getBlockCacheHitPercent() {
     if (this.cacheStats == null) {
       return 0;
     }
     return (int) (this.cacheStats.getHitRatio() * 100);
   }
 
   @Override
   public int getBlockCacheHitCachingPercent() {
     if (this.cacheStats == null) {
       return 0;
     }
     return (int) (this.cacheStats.getHitCachingRatio() * 100);
   }
 
   @Override public void forceRecompute() {
     this.runnable.run();
   }
 
   @Override
   public long getNumStores() {
     return numStores;
   }
   
   @Override
   public long getNumWALFiles() {
     return numWALFiles;
   }
 
   @Override
   public long getWALFileSize() {
     return walFileSize;
   }
   
   @Override
   public long getNumStoreFiles() {
     return numStoreFiles;
   }
 
   @Override
   public long getMemstoreSize() {
     return memstoreSize;
   }
 
   @Override
   public long getStoreFileSize() {
     return storeFileSize;
   }
 
   @Override public double getRequestsPerSecond() {
     return requestsPerSecond;
   }
 
   @Override
   public long getReadRequestsCount() {
     return readRequestsCount;
   }
 
   @Override
   public long getWriteRequestsCount() {
     return writeRequestsCount;
   }
 
   @Override
   public long getCheckAndMutateChecksFailed() {
     return checkAndMutateChecksFailed;
   }
 
   @Override
   public long getCheckAndMutateChecksPassed() {
     return checkAndMutateChecksPassed;
   }
 
   @Override
   public long getStoreFileIndexSize() {
     return storefileIndexSize;
   }
 
   @Override
   public long getTotalStaticIndexSize() {
     return totalStaticIndexSize;
   }
 
   @Override
   public long getTotalStaticBloomSize() {
     return totalStaticBloomSize;
   }
 
   @Override
   public long getNumMutationsWithoutWAL() {
     return numMutationsWithoutWAL;
   }
 
   @Override
   public long getDataInMemoryWithoutWAL() {
     return dataInMemoryWithoutWAL;
   }
 
   @Override
   public int getPercentFileLocal() {
     return percentFileLocal;
   }
 
   @Override
   public int getPercentFileLocalSecondaryRegions() {
     return percentFileLocalSecondaryRegions;
   }
 
   @Override
   public long getUpdatesBlockedTime() {
     if (this.regionServer.cacheFlusher == null) {
       return 0;
     }
     return this.regionServer.cacheFlusher.getUpdatesBlockedMsHighWater().get();
   }
 
   @Override
   public long getFlushedCellsCount() {
     return flushedCellsCount;
   }
 
   @Override
   public long getCompactedCellsCount() {
     return compactedCellsCount;
   }
 
   @Override
   public long getMajorCompactedCellsCount() {
     return majorCompactedCellsCount;
   }
 
   @Override
   public long getFlushedCellsSize() {
     return flushedCellsSize;
   }
 
   @Override
   public long getCompactedCellsSize() {
     return compactedCellsSize;
   }
 
   @Override
   public long getMajorCompactedCellsSize() {
     return majorCompactedCellsSize;
   }
 
   /**
    * This is the runnable that will be executed on the executor every PERIOD number of seconds
    * It will take metrics/numbers from all of the regions and use them to compute point in
    * time metrics.
    */
   public class RegionServerMetricsWrapperRunnable implements Runnable {
 
     private long lastRan = 0;
     private long lastRequestCount = 0;
 
     @Override
     synchronized public void run() {
       initBlockCache();
 
       HDFSBlocksDistribution hdfsBlocksDistribution =
           new HDFSBlocksDistribution();
       HDFSBlocksDistribution hdfsBlocksDistributionSecondaryRegions =
           new HDFSBlocksDistribution();
 
       long tempNumStores = 0;
       long tempNumStoreFiles = 0;
       long tempMemstoreSize = 0;
       long tempStoreFileSize = 0;
       long tempReadRequestsCount = 0;
       long tempWriteRequestsCount = 0;
       long tempCheckAndMutateChecksFailed = 0;
       long tempCheckAndMutateChecksPassed = 0;
       long tempStorefileIndexSize = 0;
       long tempTotalStaticIndexSize = 0;
       long tempTotalStaticBloomSize = 0;
       long tempNumMutationsWithoutWAL = 0;
       long tempDataInMemoryWithoutWAL = 0;
       int tempPercentFileLocal = 0;
       int tempPercentFileLocalSecondaryRegions = 0;
       long tempFlushedCellsCount = 0;
       long tempCompactedCellsCount = 0;
       long tempMajorCompactedCellsCount = 0;
       long tempFlushedCellsSize = 0;
       long tempCompactedCellsSize = 0;
       long tempMajorCompactedCellsSize = 0;
       long tempBlockedRequestsCount = 0L;
 
       for (Region r : regionServer.getOnlineRegionsLocalContext()) {
         tempNumMutationsWithoutWAL += r.getNumMutationsWithoutWAL();
         tempDataInMemoryWithoutWAL += r.getDataInMemoryWithoutWAL();
         tempReadRequestsCount += r.getReadRequestsCount();
         tempWriteRequestsCount += r.getWriteRequestsCount();
         tempCheckAndMutateChecksFailed += r.getCheckAndMutateChecksFailed();
         tempCheckAndMutateChecksPassed += r.getCheckAndMutateChecksPassed();
         tempBlockedRequestsCount += r.getBlockedRequestsCount();
         List<Store> storeList = r.getStores();
         tempNumStores += storeList.size();
         for (Store store : storeList) {
           tempNumStoreFiles += store.getStorefilesCount();
           tempMemstoreSize += store.getMemStoreSize();
           tempStoreFileSize += store.getStorefilesSize();
           tempStorefileIndexSize += store.getStorefilesIndexSize();
           tempTotalStaticBloomSize += store.getTotalStaticBloomSize();
           tempTotalStaticIndexSize += store.getTotalStaticIndexSize();
           tempFlushedCellsCount += store.getFlushedCellsCount();
           tempCompactedCellsCount += store.getCompactedCellsCount();
           tempMajorCompactedCellsCount += store.getMajorCompactedCellsCount();
           tempFlushedCellsSize += store.getFlushedCellsSize();
           tempCompactedCellsSize += store.getCompactedCellsSize();
           tempMajorCompactedCellsSize += store.getMajorCompactedCellsSize();
         }
 
         HDFSBlocksDistribution distro = r.getHDFSBlocksDistribution();
         hdfsBlocksDistribution.add(distro);
         if (r.getRegionInfo().getReplicaId() != HRegionInfo.DEFAULT_REPLICA_ID) {
           hdfsBlocksDistributionSecondaryRegions.add(distro);
         }
       }
 
       float localityIndex = hdfsBlocksDistribution.getBlockLocalityIndex(
           regionServer.getServerName().getHostname());
       tempPercentFileLocal = (int) (localityIndex * 100);
 
       float localityIndexSecondaryRegions = hdfsBlocksDistributionSecondaryRegions
           .getBlockLocalityIndex(regionServer.getServerName().getHostname());
       tempPercentFileLocalSecondaryRegions = (int) (localityIndexSecondaryRegions * 100);
 
       //Compute the number of requests per second
       long currentTime = EnvironmentEdgeManager.currentTime();
 
       // assume that it took PERIOD seconds to start the executor.
       // this is a guess but it's a pretty good one.
       if (lastRan == 0) {
         lastRan = currentTime - period;
       }
 
 
       //If we've time traveled keep the last requests per second.
       if ((currentTime - lastRan) > 0) {
         long currentRequestCount = getTotalRequestCount();
         requestsPerSecond = (currentRequestCount - lastRequestCount) /
             ((currentTime - lastRan) / 1000.0);
         lastRequestCount = currentRequestCount;
       }
       lastRan = currentTime;
 
       numWALFiles = DefaultWALProvider.getNumLogFiles(regionServer.walFactory) +
           BoundedRegionGroupingProvider.getNumLogFiles(regionServer.walFactory);
       walFileSize = DefaultWALProvider.getLogFileSize(regionServer.walFactory) +
           BoundedRegionGroupingProvider.getLogFileSize(regionServer.walFactory);
       //Copy over computed values so that no thread sees half computed values.
       numStores = tempNumStores;
       numStoreFiles = tempNumStoreFiles;
       memstoreSize = tempMemstoreSize;
       storeFileSize = tempStoreFileSize;
       readRequestsCount = tempReadRequestsCount;
       writeRequestsCount = tempWriteRequestsCount;
       checkAndMutateChecksFailed = tempCheckAndMutateChecksFailed;
       checkAndMutateChecksPassed = tempCheckAndMutateChecksPassed;
       storefileIndexSize = tempStorefileIndexSize;
       totalStaticIndexSize = tempTotalStaticIndexSize;
       totalStaticBloomSize = tempTotalStaticBloomSize;
       numMutationsWithoutWAL = tempNumMutationsWithoutWAL;
       dataInMemoryWithoutWAL = tempDataInMemoryWithoutWAL;
       percentFileLocal = tempPercentFileLocal;
       percentFileLocalSecondaryRegions = tempPercentFileLocalSecondaryRegions;
       flushedCellsCount = tempFlushedCellsCount;
       compactedCellsCount = tempCompactedCellsCount;
       majorCompactedCellsCount = tempMajorCompactedCellsCount;
       flushedCellsSize = tempFlushedCellsSize;
       compactedCellsSize = tempCompactedCellsSize;
       majorCompactedCellsSize = tempMajorCompactedCellsSize;
       blockedRequestsCount = tempBlockedRequestsCount;
     }
   }
 
   @Override
   public long getBlockedRequestsCount() {
     return blockedRequestsCount;
   }
 }