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* 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.mapreduce;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper;
import org.apache.hadoop.hbase.snapshot.SnapshotManifest;
import org.apache.hadoop.hbase.util.ConfigurationUtil;
import org.apache.hadoop.hbase.util.FSUtils;
import java.io.IOException;
import java.util.AbstractMap;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.UUID;
/**
* Shared implementation of mapreduce code over multiple table snapshots.
* Utilized by both mapreduce ({@link org.apache.hadoop.hbase.mapreduce
* .MultiTableSnapshotInputFormat} and mapred
* ({@link org.apache.hadoop.hbase.mapred.MultiTableSnapshotInputFormat} implementations.
*/
@InterfaceAudience.LimitedPrivate({ "HBase" })
@InterfaceStability.Evolving
public class MultiTableSnapshotInputFormatImpl {
private static final Log LOG = LogFactory.getLog(MultiTableSnapshotInputFormatImpl.class);
public static final String RESTORE_DIRS_KEY =
"hbase.MultiTableSnapshotInputFormat.restore.snapshotDirMapping";
public static final String SNAPSHOT_TO_SCANS_KEY =
"hbase.MultiTableSnapshotInputFormat.snapshotsToScans";
/**
* Configure conf to read from snapshotScans, with snapshots restored to a subdirectory of
* restoreDir.
* Sets: {@link #RESTORE_DIRS_KEY}, {@link #SNAPSHOT_TO_SCANS_KEY}
*
* @param conf
* @param snapshotScans
* @param restoreDir
* @throws IOException
*/
public void setInput(Configuration conf, Map<String, Collection<Scan>> snapshotScans,
Path restoreDir) throws IOException {
Path rootDir = FSUtils.getRootDir(conf);
FileSystem fs = rootDir.getFileSystem(conf);
setSnapshotToScans(conf, snapshotScans);
Map<String, Path> restoreDirs =
generateSnapshotToRestoreDirMapping(snapshotScans.keySet(), restoreDir);
setSnapshotDirs(conf, restoreDirs);
restoreSnapshots(conf, restoreDirs, fs);
}
/**
* Return the list of splits extracted from the scans/snapshots pushed to conf by
* {@link
* #setInput(org.apache.hadoop.conf.Configuration, java.util.Map, org.apache.hadoop.fs.Path)}
*
* @param conf Configuration to determine splits from
* @return Return the list of splits extracted from the scans/snapshots pushed to conf
* @throws IOException
*/
public List<TableSnapshotInputFormatImpl.InputSplit> getSplits(Configuration conf)
throws IOException {
Path rootDir = FSUtils.getRootDir(conf);
FileSystem fs = rootDir.getFileSystem(conf);
List<TableSnapshotInputFormatImpl.InputSplit> rtn = Lists.newArrayList();
Map<String, Collection<Scan>> snapshotsToScans = getSnapshotsToScans(conf);
Map<String, Path> snapshotsToRestoreDirs = getSnapshotDirs(conf);
for (Map.Entry<String, Collection<Scan>> entry : snapshotsToScans.entrySet()) {
String snapshotName = entry.getKey();
Path restoreDir = snapshotsToRestoreDirs.get(snapshotName);
SnapshotManifest manifest =
TableSnapshotInputFormatImpl.getSnapshotManifest(conf, snapshotName, rootDir, fs);
List<HRegionInfo> regionInfos =
TableSnapshotInputFormatImpl.getRegionInfosFromManifest(manifest);
for (Scan scan : entry.getValue()) {
List<TableSnapshotInputFormatImpl.InputSplit> splits =
TableSnapshotInputFormatImpl.getSplits(scan, manifest, regionInfos, restoreDir, conf);
rtn.addAll(splits);
}
}
return rtn;
}
/**
* Retrieve the snapshot name -> list<scan> mapping pushed to configuration by
* {@link #setSnapshotToScans(org.apache.hadoop.conf.Configuration, java.util.Map)}
*
* @param conf Configuration to extract name -> list<scan> mappings from.
* @return the snapshot name -> list<scan> mapping pushed to configuration
* @throws IOException
*/
public Map<String, Collection<Scan>> getSnapshotsToScans(Configuration conf) throws IOException {
Map<String, Collection<Scan>> rtn = Maps.newHashMap();
for (Map.Entry<String, String> entry : ConfigurationUtil
.getKeyValues(conf, SNAPSHOT_TO_SCANS_KEY)) {
String snapshotName = entry.getKey();
String scan = entry.getValue();
Collection<Scan> snapshotScans = rtn.get(snapshotName);
if (snapshotScans == null) {
snapshotScans = Lists.newArrayList();
rtn.put(snapshotName, snapshotScans);
}
snapshotScans.add(TableMapReduceUtil.convertStringToScan(scan));
}
return rtn;
}
/**
* Push snapshotScans to conf (under the key {@link #SNAPSHOT_TO_SCANS_KEY})
*
* @param conf
* @param snapshotScans
* @throws IOException
*/
public void setSnapshotToScans(Configuration conf, Map<String, Collection<Scan>> snapshotScans)
throws IOException {
// flatten out snapshotScans for serialization to the job conf
List<Map.Entry<String, String>> snapshotToSerializedScans = Lists.newArrayList();
for (Map.Entry<String, Collection<Scan>> entry : snapshotScans.entrySet()) {
String snapshotName = entry.getKey();
Collection<Scan> scans = entry.getValue();
// serialize all scans and map them to the appropriate snapshot
for (Scan scan : scans) {
snapshotToSerializedScans.add(new AbstractMap.SimpleImmutableEntry<>(snapshotName,
TableMapReduceUtil.convertScanToString(scan)));
}
}
ConfigurationUtil.setKeyValues(conf, SNAPSHOT_TO_SCANS_KEY, snapshotToSerializedScans);
}
/**
* Retrieve the directories into which snapshots have been restored from
* ({@link #RESTORE_DIRS_KEY})
*
* @param conf Configuration to extract restore directories from
* @return the directories into which snapshots have been restored from
* @throws IOException
*/
public Map<String, Path> getSnapshotDirs(Configuration conf) throws IOException {
List<Map.Entry<String, String>> kvps = ConfigurationUtil.getKeyValues(conf, RESTORE_DIRS_KEY);
Map<String, Path> rtn = Maps.newHashMapWithExpectedSize(kvps.size());
for (Map.Entry<String, String> kvp : kvps) {
rtn.put(kvp.getKey(), new Path(kvp.getValue()));
}
return rtn;
}
public void setSnapshotDirs(Configuration conf, Map<String, Path> snapshotDirs) {
Map<String, String> toSet = Maps.newHashMap();
for (Map.Entry<String, Path> entry : snapshotDirs.entrySet()) {
toSet.put(entry.getKey(), entry.getValue().toString());
}
ConfigurationUtil.setKeyValues(conf, RESTORE_DIRS_KEY, toSet.entrySet());
}
/**
* Generate a random path underneath baseRestoreDir for each snapshot in snapshots and
* return a map from the snapshot to the restore directory.
*
* @param snapshots collection of snapshot names to restore
* @param baseRestoreDir base directory under which all snapshots in snapshots will be restored
* @return a mapping from snapshot name to the directory in which that snapshot has been restored
*/
private Map<String, Path> generateSnapshotToRestoreDirMapping(Collection<String> snapshots,
Path baseRestoreDir) {
Map<String, Path> rtn = Maps.newHashMap();
for (String snapshotName : snapshots) {
Path restoreSnapshotDir =
new Path(baseRestoreDir, snapshotName + "__" + UUID.randomUUID().toString());
rtn.put(snapshotName, restoreSnapshotDir);
}
return rtn;
}
/**
* Restore each (snapshot name, restore directory) pair in snapshotToDir
*
* @param conf configuration to restore with
* @param snapshotToDir mapping from snapshot names to restore directories
* @param fs filesystem to do snapshot restoration on
* @throws IOException
*/
public void restoreSnapshots(Configuration conf, Map<String, Path> snapshotToDir, FileSystem fs)
throws IOException {
// TODO: restore from record readers to parallelize.
Path rootDir = FSUtils.getRootDir(conf);
for (Map.Entry<String, Path> entry : snapshotToDir.entrySet()) {
String snapshotName = entry.getKey();
Path restoreDir = entry.getValue();
LOG.info("Restoring snapshot " + snapshotName + " into " + restoreDir
+ " for MultiTableSnapshotInputFormat");
restoreSnapshot(conf, snapshotName, rootDir, restoreDir, fs);
}
}
void restoreSnapshot(Configuration conf, String snapshotName, Path rootDir, Path restoreDir,
FileSystem fs) throws IOException {
RestoreSnapshotHelper.copySnapshotForScanner(conf, fs, rootDir, restoreDir, snapshotName);
}
}