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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  import java.util.Collections;
23  
24  import org.apache.commons.logging.Log;
25  import org.apache.commons.logging.LogFactory;
26  import org.apache.hadoop.classification.InterfaceAudience;
27  import org.apache.hadoop.classification.InterfaceStability;
28  import org.apache.hadoop.conf.Configuration;
29  import org.apache.hadoop.fs.FileStatus;
30  import org.apache.hadoop.fs.FileSystem;
31  import org.apache.hadoop.fs.Path;
32  import org.apache.hadoop.hbase.master.cleaner.BaseLogCleanerDelegate;
33  import org.apache.hadoop.hbase.snapshot.SnapshotReferenceUtil;
34  import org.apache.hadoop.hbase.util.FSUtils;
35  
36  /**
37   * Implementation of a log cleaner that checks if a log is still used by
38   * snapshots of HBase tables.
39   */
40  @InterfaceAudience.Private
41  @InterfaceStability.Evolving
42  public class SnapshotLogCleaner extends BaseLogCleanerDelegate {
43    private static final Log LOG = LogFactory.getLog(SnapshotLogCleaner.class);
44  
45    /**
46     * Conf key for the frequency to attempt to refresh the cache of hfiles currently used in
47     * snapshots (ms)
48     */
49    static final String HLOG_CACHE_REFRESH_PERIOD_CONF_KEY =
50        "hbase.master.hlogcleaner.plugins.snapshot.period";
51  
52    /** Refresh cache, by default, every 5 minutes */
53    private static final long DEFAULT_HLOG_CACHE_REFRESH_PERIOD = 300000;
54  
55    private SnapshotFileCache cache;
56  
57    @Override
58    public synchronized Iterable<FileStatus> getDeletableFiles(Iterable<FileStatus> files) {
59      if (null == cache) return Collections.emptyList();
60      try {
61        return cache.getUnreferencedFiles(files);
62      } catch (IOException e) {
63        LOG.error("Exception while checking if files were valid, keeping them just in case.", e);
64        return Collections.emptyList();
65      }
66    }
67  
68    /**
69     * This method should only be called <b>once</b>, as it starts a thread to keep the cache
70     * up-to-date.
71     * <p>
72     * {@inheritDoc}
73     */
74    @Override
75    public void setConf(Configuration conf) {
76      super.setConf(conf);
77      try {
78        long cacheRefreshPeriod = conf.getLong(
79          HLOG_CACHE_REFRESH_PERIOD_CONF_KEY, DEFAULT_HLOG_CACHE_REFRESH_PERIOD);
80        final FileSystem fs = FSUtils.getCurrentFileSystem(conf);
81        Path rootDir = FSUtils.getRootDir(conf);
82        cache = new SnapshotFileCache(fs, rootDir, cacheRefreshPeriod, cacheRefreshPeriod,
83            "snapshot-log-cleaner-cache-refresher", new SnapshotFileCache.SnapshotFileInspector() {
84              public Collection<String> filesUnderSnapshot(final Path snapshotDir)
85                  throws IOException {
86                return SnapshotReferenceUtil.getHLogNames(fs, snapshotDir);
87              }
88            });
89      } catch (IOException e) {
90        LOG.error("Failed to create snapshot log cleaner", e);
91      }
92    }
93  
94    @Override
95    public void stop(String why) {
96      this.cache.stop(why);
97    }
98  
99    @Override
100   public boolean isStopped() {
101     return this.cache.isStopped();
102   }
103 }