/**
*
* 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.TableName;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.NotAllMetaRegionsOnlineException;
import org.apache.hadoop.hbase.TableExistsException;
import org.apache.hadoop.hbase.errorhandling.ForeignException;
import org.apache.hadoop.hbase.errorhandling.ForeignExceptionDispatcher;
import org.apache.hadoop.hbase.master.MasterServices;
import org.apache.hadoop.hbase.master.MetricsSnapshot;
import org.apache.hadoop.hbase.master.SnapshotSentinel;
import org.apache.hadoop.hbase.master.handler.CreateTableHandler;
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.ClientSnapshotDescriptionUtils;
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.snapshot.SnapshotManifest;
import com.google.common.base.Preconditions;
/**
* Handler to Clone a snapshot.
*
* <p>Uses {@link RestoreSnapshotHelper} to create a new table with the same
* content of the specified snapshot.
*/
@InterfaceAudience.Private
public class CloneSnapshotHandler extends CreateTableHandler implements SnapshotSentinel {
private static final Log LOG = LogFactory.getLog(CloneSnapshotHandler.class);
private final static String NAME = "Master CloneSnapshotHandler";
private final SnapshotDescription snapshot;
private final ForeignExceptionDispatcher monitor;
private final MetricsSnapshot metricsSnapshot = new MetricsSnapshot();
private final MonitoredTask status;
private RestoreSnapshotHelper.RestoreMetaChanges metaChanges;
private volatile boolean stopped = false;
public CloneSnapshotHandler(final MasterServices masterServices,
final SnapshotDescription snapshot, final HTableDescriptor hTableDescriptor) {
super(masterServices, masterServices.getMasterFileSystem(), hTableDescriptor,
masterServices.getConfiguration(), null, masterServices);
// Snapshot information
this.snapshot = snapshot;
// Monitor
this.monitor = new ForeignExceptionDispatcher();
this.status = TaskMonitor.get().createStatus("Cloning snapshot '" + snapshot.getName() +
"' to table " + hTableDescriptor.getTableName());
}
@Override
public CloneSnapshotHandler prepare() throws NotAllMetaRegionsOnlineException,
TableExistsException, IOException {
return (CloneSnapshotHandler) super.prepare();
}
/**
* Create the on-disk regions, using the tableRootDir provided by the CreateTableHandler.
* The cloned table will be created in a temp directory, and then the CreateTableHandler
* will be responsible to add the regions returned by this method to hbase:meta and do the assignment.
*/
@Override
protected List<HRegionInfo> handleCreateHdfsRegions(final Path tableRootDir,
final TableName tableName) throws IOException {
status.setStatus("Creating regions for table: " + tableName);
FileSystem fs = fileSystemManager.getFileSystem();
Path rootDir = fileSystemManager.getRootDir();
try {
// 1. Execute the on-disk Clone
Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(snapshot, rootDir);
SnapshotManifest manifest = SnapshotManifest.open(conf, fs, snapshotDir, snapshot);
RestoreSnapshotHelper restoreHelper = new RestoreSnapshotHelper(conf, fs,
manifest, hTableDescriptor, tableRootDir, monitor, status);
metaChanges = restoreHelper.restoreHdfsRegions();
// Clone operation should not have stuff to restore or remove
Preconditions.checkArgument(!metaChanges.hasRegionsToRestore(),
"A clone should not have regions to restore");
Preconditions.checkArgument(!metaChanges.hasRegionsToRemove(),
"A clone should not have regions to remove");
// At this point the clone is complete. Next step is enabling the table.
String msg = "Clone snapshot="+ snapshot.getName() +" on table=" + tableName + " completed!";
LOG.info(msg);
status.setStatus(msg + " Waiting for table to be enabled...");
// 2. let the CreateTableHandler add the regions to meta
return metaChanges.getRegionsToAdd();
} catch (Exception e) {
String msg = "clone snapshot=" + ClientSnapshotDescriptionUtils.toString(snapshot) +
" failed because " + e.getMessage();
LOG.error(msg, e);
IOException rse = new RestoreSnapshotException(msg, e, snapshot);
// these handlers aren't futures so we need to register the error here.
this.monitor.receive(new ForeignException(NAME, rse));
throw rse;
}
}
@Override
protected void addRegionsToMeta(final List<HRegionInfo> regionInfos)
throws IOException {
super.addRegionsToMeta(regionInfos);
metaChanges.updateMetaParentRegions(this.server.getShortCircuitConnection(), regionInfos);
}
@Override
protected void completed(final Throwable exception) {
this.stopped = true;
if (exception != null) {
status.abort("Snapshot '" + snapshot.getName() + "' clone failed because " +
exception.getMessage());
} else {
status.markComplete("Snapshot '"+ snapshot.getName() +"' clone completed and table enabled!");
}
metricsSnapshot.addSnapshotClone(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 clone snapshot=" + snapshot + " because: " + why;
LOG.info(msg);
status.abort(msg);
this.monitor.receive(new ForeignException(NAME, new CancellationException(why)));
}
@Override
public ForeignException getExceptionIfFailed() {
return this.monitor.getException();
}
@Override
public void rethrowExceptionIfFailed() throws ForeignException {
monitor.rethrowException();
}
}