hbase-hbck2/src/main/java/org/apache/hbase/FsRegionsMetaRecoverer.java

/*
 * 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.hbase;

import java.io.Closeable;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.MetaTableAccessor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.regionserver.HRegionFileSystem;
import org.apache.hadoop.hbase.util.CommonFSUtils;
import org.apache.hadoop.hbase.util.FSUtils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * This class implements the inner works required for check and recover regions that wrongly
 * went missing in META.
 * Normally HBCK2 fix options rely on Master self-contained information to recover/fix
 * inconsistencies, but this an exception case where META table is in a broken state.
 * So, it assumes HDFS state as the source of truth, in other words, methods provided here consider
 * meta information found on HDFS region dirs as the valid ones.
 */
public class FsRegionsMetaRecoverer implements Closeable {
  private static final Logger LOG = LoggerFactory.getLogger(FsRegionsMetaRecoverer.class);
  private final FileSystem fs;
  private final Connection conn;
  private final Configuration config;

  public FsRegionsMetaRecoverer(Configuration configuration) throws IOException {
    this.config = configuration;
    this.fs = CommonFSUtils.getRootDirFileSystem(configuration);
    this.conn = ConnectionFactory.createConnection(configuration);
  }

  /*Initially defined for test only purposes */
  FsRegionsMetaRecoverer(Configuration configuration, Connection connection, FileSystem fileSystem){
    this.config = configuration;
    this.conn = connection;
    this.fs = fileSystem;
  }

  private List<Path> getTableRegionsDirs(String table) throws Exception {
    String hbaseRoot = this.config.get(HConstants.HBASE_DIR);
    Path tableDir = FSUtils.getTableDir(new Path(hbaseRoot), TableName.valueOf(table));
    return FSUtils.getRegionDirs(fs, tableDir);
  }

  public Map<TableName,List<Path>> reportTablesMissingRegions(final List<String> namespacesOrTables)
      throws IOException {
    final Map<TableName,List<Path>> result = new HashMap<>();
    List<TableName> tableNames = MetaTableAccessor.getTableStates(this.conn).keySet().stream()
      .filter(tableName -> {
        if(namespacesOrTables==null || namespacesOrTables.isEmpty()){
          return true;
        } else {
          Optional<String> findings = namespacesOrTables.stream().filter(
            name -> (name.indexOf(":") > 0) ?
              tableName.equals(TableName.valueOf(name)) :
              tableName.getNamespaceAsString().equals(name)).findFirst();
          return findings.isPresent();
        }
      }).collect(Collectors.toList());
    tableNames.stream().forEach(tableName -> {
      try {
        result.put(tableName,
          findMissingRegionsInMETA(tableName.getNameWithNamespaceInclAsString()));
      } catch (Exception e) {
        LOG.warn("Can't get missing regions from meta", e);
      }
    });
    return result;
  }

  List<Path> findMissingRegionsInMETA(String table) throws Exception {
    final List<Path> missingRegions = new ArrayList<>();
    final List<Path> regionsDirs = getTableRegionsDirs(table);
    TableName tableName = TableName.valueOf(table);
    List<RegionInfo> regionInfos = MetaTableAccessor.
      getTableRegions(this.conn, tableName, false);
    HashSet<String> regionsInMeta = regionInfos.stream().map(info ->
      info.getEncodedName()).collect(Collectors.toCollection(HashSet::new));
    for(final Path regionDir : regionsDirs){
      if (!regionsInMeta.contains(regionDir.getName())) {
        LOG.debug(regionDir + "is not in META.");
        missingRegions.add(regionDir);
      }
    }
    return missingRegions;
  }

  public void putRegionInfoFromHdfsInMeta(Path region) throws IOException {
    RegionInfo info = HRegionFileSystem.loadRegionInfoFileContent(fs, region);
    MetaTableAccessor.addRegionToMeta(conn, info);
  }

  @Override public void close() throws IOException {
    this.conn.close();
  }
}