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1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.hadoop.hbase.master.snapshot;
19  
20  import java.io.IOException;
21  import java.util.Collection;
22  
23  import org.apache.commons.logging.Log;
24  import org.apache.commons.logging.LogFactory;
25  import org.apache.hadoop.classification.InterfaceAudience;
26  import org.apache.hadoop.classification.InterfaceStability;
27  import org.apache.hadoop.conf.Configuration;
28  import org.apache.hadoop.fs.FileSystem;
29  import org.apache.hadoop.fs.Path;
30  import org.apache.hadoop.hbase.master.cleaner.BaseLogCleanerDelegate;
31  import org.apache.hadoop.hbase.snapshot.SnapshotReferenceUtil;
32  import org.apache.hadoop.hbase.util.FSUtils;
33  
34  /**
35   * Implementation of a log cleaner that checks if a log is still used by
36   * snapshots of HBase tables.
37   */
38  @InterfaceAudience.Private
39  @InterfaceStability.Evolving
40  public class SnapshotLogCleaner extends BaseLogCleanerDelegate {
41    private static final Log LOG = LogFactory.getLog(SnapshotLogCleaner.class);
42  
43    /**
44     * Conf key for the frequency to attempt to refresh the cache of hfiles currently used in
45     * snapshots (ms)
46     */
47    static final String HLOG_CACHE_REFRESH_PERIOD_CONF_KEY =
48        "hbase.master.hlogcleaner.plugins.snapshot.period";
49  
50    /** Refresh cache, by default, every 5 minutes */
51    private static final long DEFAULT_HLOG_CACHE_REFRESH_PERIOD = 300000;
52  
53    private SnapshotFileCache cache;
54  
55    @Override
56    public synchronized boolean isLogDeletable(Path filePath) {
57      try {
58        if (null == cache) return false;
59        return !cache.contains(filePath.getName());
60      } catch (IOException e) {
61        LOG.error("Exception while checking if:" + filePath + " was valid, keeping it just in case.",
62          e);
63        return false;
64      }
65    }
66  
67    /**
68     * This method should only be called <b>once</b>, as it starts a thread to keep the cache
69     * up-to-date.
70     * <p>
71     * {@inheritDoc}
72     */
73    @Override
74    public void setConf(Configuration conf) {
75      super.setConf(conf);
76      try {
77        long cacheRefreshPeriod = conf.getLong(
78          HLOG_CACHE_REFRESH_PERIOD_CONF_KEY, DEFAULT_HLOG_CACHE_REFRESH_PERIOD);
79        final FileSystem fs = FSUtils.getCurrentFileSystem(conf);
80        Path rootDir = FSUtils.getRootDir(conf);
81        cache = new SnapshotFileCache(fs, rootDir, cacheRefreshPeriod, cacheRefreshPeriod,
82            "snapshot-log-cleaner-cache-refresher", new SnapshotFileCache.SnapshotFileInspector() {
83              public Collection<String> filesUnderSnapshot(final Path snapshotDir)
84                  throws IOException {
85                return SnapshotReferenceUtil.getHLogNames(fs, snapshotDir);
86              }
87            });
88      } catch (IOException e) {
89        LOG.error("Failed to create snapshot log cleaner", e);
90      }
91    }
92  
93    @Override
94    public void stop(String why) {
95      this.cache.stop(why);
96    }
97  
98    @Override
99    public boolean isStopped() {
100     return this.cache.isStopped();
101   }
102 }