/*
    *
    * 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.namequeues;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.locks.ReentrantLock;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.namequeues.queue.EvictingQueue;
  import org.apache.hadoop.hbase.protobuf.generated.TooSlowLog;
  import org.apache.hadoop.hbase.slowlog.SlowLogTableAccessor;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Persistent service provider for Slow/LargeLog events
   */
  @InterfaceAudience.Private
  public class SlowLogPersistentService {
  
    private static final Logger LOG = LoggerFactory.getLogger(SlowLogPersistentService.class);
  
    private static final ReentrantLock LOCK = new ReentrantLock();
    private static final String SYS_TABLE_QUEUE_SIZE =
      "hbase.regionserver.slowlog.systable.queue.size";
    private static final int DEFAULT_SYS_TABLE_QUEUE_SIZE = 1000;
    private static final int SYSTABLE_PUT_BATCH_SIZE = 100;
  
    private final EvictingQueue<TooSlowLog.SlowLogPayload> queueForSysTable;
  
    private final Configuration configuration;
  
    public SlowLogPersistentService(final Configuration configuration) {
      this.configuration = configuration;
      int sysTableQueueSize =
        configuration.getInt(SYS_TABLE_QUEUE_SIZE, DEFAULT_SYS_TABLE_QUEUE_SIZE);
      queueForSysTable = EvictingQueue.create(sysTableQueueSize);
    }
  
    public void addToQueueForSysTable(TooSlowLog.SlowLogPayload slowLogPayload) {
      queueForSysTable.add(slowLogPayload);
    }
  
    /**
     * Poll from queueForSysTable and insert 100 records in hbase:slowlog table in single batch
     */
    public void addAllLogsToSysTable() {
      if (queueForSysTable == null) {
        LOG.trace("hbase.regionserver.slowlog.systable.enabled is turned off. Exiting.");
        return;
      }
      if (LOCK.isLocked()) {
        return;
      }
      LOCK.lock();
      try {
        List<TooSlowLog.SlowLogPayload> slowLogPayloads = new ArrayList<>();
        int i = 0;
        while (!queueForSysTable.isEmpty()) {
          slowLogPayloads.add(queueForSysTable.poll());
          i++;
          if (i == SYSTABLE_PUT_BATCH_SIZE) {
            SlowLogTableAccessor.addSlowLogRecords(slowLogPayloads, this.configuration);
            slowLogPayloads.clear();
            i = 0;
          }
        }
        if (slowLogPayloads.size() > 0) {
          SlowLogTableAccessor.addSlowLogRecords(slowLogPayloads, this.configuration);
        }
      } finally {
        LOCK.unlock();
      }
    }
  
  }