/*
    * 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.master.cleaner;
  
  import java.io.IOException;
  import java.util.List;
  import java.util.concurrent.TimeUnit;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.ScheduledChore;
  import org.apache.hadoop.hbase.Stoppable;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.master.snapshot.SnapshotManager;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
  import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
  
  /**
   * This chore, every time it runs, will try to delete snapshots that are expired based on TTL in
   * seconds configured for each Snapshot
   */
  @InterfaceAudience.Private
  public class SnapshotCleanerChore extends ScheduledChore {
  
    private static final Log LOG = LogFactory.getLog(SnapshotCleanerChore.class);
    private static final String SNAPSHOT_CLEANER_CHORE_NAME = "SnapshotCleaner";
    private static final String SNAPSHOT_CLEANER_INTERVAL = "hbase.master.cleaner.snapshot.interval";
    private static final int SNAPSHOT_CLEANER_DEFAULT_INTERVAL = 1800 * 1000; // Default 30 min
    private static final String DELETE_SNAPSHOT_EVENT =
        "Eligible Snapshot for cleanup due to expired TTL.";
  
    private final SnapshotManager snapshotManager;
  
    /**
     * Construct Snapshot Cleaner Chore with parameterized constructor
     *
     * @param stopper When {@link Stoppable#isStopped()} is true, this chore will cancel and cleanup
     * @param configuration The configuration to set
     * @param snapshotManager SnapshotManager instance to manage lifecycle of snapshot
     */
    public SnapshotCleanerChore(Stoppable stopper, Configuration configuration,
            SnapshotManager snapshotManager) {
      super(SNAPSHOT_CLEANER_CHORE_NAME, stopper, configuration.getInt(SNAPSHOT_CLEANER_INTERVAL,
        SNAPSHOT_CLEANER_DEFAULT_INTERVAL));
      this.snapshotManager = snapshotManager;
    }
  
    @Override
    protected void chore() {
      if (LOG.isTraceEnabled()) {
        LOG.trace("Snapshot Cleaner Chore is starting up...");
      }
      try {
        List<SnapshotDescription> completedSnapshotsList =
            this.snapshotManager.getCompletedSnapshots();
        for (SnapshotDescription snapshotDescription : completedSnapshotsList) {
          long snapshotCreatedTime = snapshotDescription.getCreationTime();
          long snapshotTtl = snapshotDescription.getTtl();
          /*
           * Backward compatibility after the patch deployment on HMaster
           * Any snapshot with ttl 0 is to be considered as snapshot to keep FOREVER
           * Default ttl value specified by {@HConstants.DEFAULT_SNAPSHOT_TTL}
           */
          if (snapshotCreatedTime > 0 && snapshotTtl > 0 &&
              snapshotTtl < TimeUnit.MILLISECONDS.toSeconds(Long.MAX_VALUE)) {
            long currentTime = EnvironmentEdgeManager.currentTime();
            if ((snapshotCreatedTime + TimeUnit.SECONDS.toMillis(snapshotTtl)) < currentTime) {
              LOG.info("Event: " + DELETE_SNAPSHOT_EVENT + " Name: " + snapshotDescription.getName() +
                ", CreatedTime: " + snapshotCreatedTime + ", TTL: " + snapshotTtl +
                ", currentTime: " + currentTime);
              deleteExpiredSnapshot(snapshotDescription);
            }
          }
        }
      } catch (IOException e) {
        LOG.error("Error while cleaning up Snapshots...", e);
      }
      if (LOG.isTraceEnabled()) {
        LOG.trace("Snapshot Cleaner Chore is closing...");
      }
    }
  
    private void deleteExpiredSnapshot(SnapshotDescription snapshotDescription) {
     try {
       this.snapshotManager.deleteSnapshot(snapshotDescription);
     } catch (Exception e) {
       LOG.error("Error while deleting Snapshot: " + snapshotDescription.getName(), e);
     }
   }
 
 }