001/**
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019package org.apache.hadoop.hbase.wal;
020
021import java.io.IOException;
022import org.apache.hadoop.conf.Configuration;
023import org.apache.hadoop.fs.FileSystem;
024import org.apache.hadoop.fs.Path;
025import org.apache.hadoop.hbase.regionserver.wal.FSHLog;
026import org.apache.hadoop.hbase.regionserver.wal.ProtobufLogWriter;
027import org.apache.hadoop.hbase.regionserver.wal.WALUtil;
028import org.apache.hadoop.hbase.util.CommonFSUtils;
029import org.apache.hadoop.hbase.util.CommonFSUtils.StreamLacksCapabilityException;
030import org.apache.yetus.audience.InterfaceAudience;
031import org.apache.yetus.audience.InterfaceStability;
032import org.slf4j.Logger;
033import org.slf4j.LoggerFactory;
034
035/**
036 * A WAL provider that use {@link FSHLog}.
037 */
038@InterfaceAudience.Private
039@InterfaceStability.Evolving
040public class FSHLogProvider extends AbstractFSWALProvider<FSHLog> {
041
042  private static final Logger LOG = LoggerFactory.getLogger(FSHLogProvider.class);
043
044  // Only public so classes back in regionserver.wal can access
045  public interface Writer extends WALProvider.Writer {
046    /**
047     * @throws IOException if something goes wrong initializing an output stream
048     * @throws StreamLacksCapabilityException if the given FileSystem can't provide streams that
049     *         meet the needs of the given Writer implementation.
050     */
051    void init(FileSystem fs, Path path, Configuration c, boolean overwritable, long blocksize)
052        throws IOException, CommonFSUtils.StreamLacksCapabilityException;
053  }
054
055  /**
056   * Public because of FSHLog. Should be package-private
057   * @param overwritable if the created writer can overwrite. For recovered edits, it is true and
058   *          for WAL it is false. Thus we can distinguish WAL and recovered edits by this.
059   */
060  public static Writer createWriter(final Configuration conf, final FileSystem fs, final Path path,
061      final boolean overwritable) throws IOException {
062    return createWriter(conf, fs, path, overwritable,
063      WALUtil.getWALBlockSize(conf, fs, path, overwritable));
064  }
065
066  /**
067   * Public because of FSHLog. Should be package-private
068   */
069  public static Writer createWriter(final Configuration conf, final FileSystem fs, final Path path,
070    final boolean overwritable, long blocksize) throws IOException {
071    // Configuration already does caching for the Class lookup.
072    Class<? extends Writer> logWriterClass =
073        conf.getClass("hbase.regionserver.hlog.writer.impl", ProtobufLogWriter.class,
074            Writer.class);
075    Writer writer = null;
076    try {
077      writer = logWriterClass.getDeclaredConstructor().newInstance();
078      FileSystem rootFs = FileSystem.get(path.toUri(), conf);
079      writer.init(rootFs, path, conf, overwritable, blocksize);
080      return writer;
081    } catch (Exception e) { 
082      if (e instanceof CommonFSUtils.StreamLacksCapabilityException) {
083        LOG.error("The RegionServer write ahead log provider for FileSystem implementations " +
084            "relies on the ability to call " + e.getMessage() + " for proper operation during " +
085            "component failures, but the current FileSystem does not support doing so. Please " +
086            "check the config value of '" + CommonFSUtils.HBASE_WAL_DIR + "' and ensure " +
087            "it points to a FileSystem mount that has suitable capabilities for output streams.");
088      } else {
089        LOG.debug("Error instantiating log writer.", e);
090      }
091      if (writer != null) {
092        try{
093          writer.close();
094        } catch(IOException ee){
095          LOG.error("cannot close log writer", ee);
096        }
097      }
098      throw new IOException("cannot get log writer", e);
099    }
100  }
101
102  @Override
103  protected FSHLog createWAL() throws IOException {
104    return new FSHLog(CommonFSUtils.getWALFileSystem(conf), CommonFSUtils.getWALRootDir(conf),
105        getWALDirectoryName(factory.factoryId),
106        getWALArchiveDirectoryName(conf, factory.factoryId), conf, listeners, true, logPrefix,
107        META_WAL_PROVIDER_ID.equals(providerId) ? META_WAL_PROVIDER_ID : null);
108  }
109
110  @Override
111  protected void doInit(Configuration conf) throws IOException {
112  }
113}