/**
*
* 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.master.snapshot;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.CancellationException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.catalog.CatalogTracker;
import org.apache.hadoop.hbase.catalog.MetaEditor;
import org.apache.hadoop.hbase.errorhandling.ForeignException;
import org.apache.hadoop.hbase.errorhandling.ForeignExceptionDispatcher;
import org.apache.hadoop.hbase.master.MasterFileSystem;
import org.apache.hadoop.hbase.master.MasterServices;
import org.apache.hadoop.hbase.master.SnapshotSentinel;
import org.apache.hadoop.hbase.master.handler.TableEventHandler;
import org.apache.hadoop.hbase.master.metrics.MasterMetrics;
import org.apache.hadoop.hbase.monitoring.MonitoredTask;
import org.apache.hadoop.hbase.monitoring.TaskMonitor;
import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
import org.apache.hadoop.hbase.snapshot.RestoreSnapshotException;
import org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper;
import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;
import org.apache.hadoop.hbase.util.Bytes;
/**
* Handler to Restore a snapshot.
*
* <p>Uses {@link RestoreSnapshotHelper} to replace the table content with the
* data available in the snapshot.
*/
@InterfaceAudience.Private
public class RestoreSnapshotHandler extends TableEventHandler implements SnapshotSentinel {
private static final Log LOG = LogFactory.getLog(RestoreSnapshotHandler.class);
private final HTableDescriptor hTableDescriptor;
private final SnapshotDescription snapshot;
private final ForeignExceptionDispatcher monitor;
private final MasterMetrics metricsMaster;
private final MonitoredTask status;
private volatile boolean stopped = false;
public RestoreSnapshotHandler(final MasterServices masterServices,
final SnapshotDescription snapshot, final HTableDescriptor htd,
final MasterMetrics metricsMaster) throws IOException {
super(EventType.C_M_RESTORE_SNAPSHOT, htd.getName(), masterServices, masterServices);
this.metricsMaster = metricsMaster;
// Snapshot information
this.snapshot = snapshot;
// Monitor
this.monitor = new ForeignExceptionDispatcher();
// Check table exists.
getTableDescriptor();
// This is the new schema we are going to write out as this modification.
this.hTableDescriptor = htd;
this.status = TaskMonitor.get().createStatus(
"Restoring snapshot '" + snapshot.getName() + "' to table "
+ hTableDescriptor.getNameAsString());
}
/**
* The restore table is executed in place.
* - The on-disk data will be restored - reference files are put in place without moving data
* - [if something fail here: you need to delete the table and re-run the restore]
* - META will be updated
* - [if something fail here: you need to run hbck to fix META entries]
* The passed in list gets changed in this method
*/
@Override
protected void handleTableOperation(List<HRegionInfo> hris) throws IOException {
MasterFileSystem fileSystemManager = masterServices.getMasterFileSystem();
CatalogTracker catalogTracker = masterServices.getCatalogTracker();
FileSystem fs = fileSystemManager.getFileSystem();
Path rootDir = fileSystemManager.getRootDir();
byte[] tableName = hTableDescriptor.getName();
Path tableDir = HTableDescriptor.getTableDir(rootDir, tableName);
try {
// 1. Update descriptor
this.masterServices.getTableDescriptors().add(hTableDescriptor);
// 2. Execute the on-disk Restore
LOG.debug("Starting restore snapshot=" + SnapshotDescriptionUtils.toString(snapshot));
Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(snapshot, rootDir);
RestoreSnapshotHelper restoreHelper = new RestoreSnapshotHelper(
masterServices.getConfiguration(), fs,
snapshot, snapshotDir, hTableDescriptor, tableDir, monitor, status);
RestoreSnapshotHelper.RestoreMetaChanges metaChanges = restoreHelper.restoreHdfsRegions();
// 3. Applies changes to .META.
hris.clear();
status.setStatus("Preparing to restore each region");
if (metaChanges.hasRegionsToAdd()) hris.addAll(metaChanges.getRegionsToAdd());
if (metaChanges.hasRegionsToRestore()) hris.addAll(metaChanges.getRegionsToRestore());
List<HRegionInfo> hrisToRemove = metaChanges.getRegionsToRemove();
MetaEditor.mutateRegions(catalogTracker, hrisToRemove, hris);
// At this point the restore is complete. Next step is enabling the table.
LOG.info("Restore snapshot=" + SnapshotDescriptionUtils.toString(snapshot) + " on table=" +
Bytes.toString(tableName) + " completed!");
} catch (IOException e) {
String msg = "restore snapshot=" + SnapshotDescriptionUtils.toString(snapshot)
+ " failed. Try re-running the restore command.";
LOG.error(msg, e);
monitor.receive(new ForeignException(masterServices.getServerName().toString(), e));
throw new RestoreSnapshotException(msg, e);
} finally {
this.stopped = true;
}
}
@Override
protected void completed(final Throwable exception) {
this.stopped = true;
if (exception != null) {
status.abort("Restore snapshot '" + snapshot.getName() + "' failed because " +
exception.getMessage());
} else {
status.markComplete("Restore snapshot '"+ snapshot.getName() +"' completed!");
}
metricsMaster.addSnapshotRestore(status.getCompletionTimestamp() - status.getStartTime());
super.completed(exception);
}
@Override
public boolean isFinished() {
return this.stopped;
}
@Override
public long getCompletionTimestamp() {
return this.status.getCompletionTimestamp();
}
@Override
public SnapshotDescription getSnapshot() {
return snapshot;
}
@Override
public void cancel(String why) {
if (this.stopped) return;
this.stopped = true;
String msg = "Stopping restore snapshot=" + SnapshotDescriptionUtils.toString(snapshot)
+ " because: " + why;
LOG.info(msg);
CancellationException ce = new CancellationException(why);
this.monitor.receive(new ForeignException(masterServices.getServerName().toString(), ce));
}
@Override
public ForeignException getExceptionIfFailed() {
return this.monitor.getException();
}
@Override
public void rethrowExceptionIfFailed() throws ForeignException {
monitor.rethrowException();
}
}