/**
*
* 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.errorhandling.ForeignException;
import org.apache.hadoop.hbase.errorhandling.ForeignExceptionDispatcher;
import org.apache.hadoop.hbase.exceptions.NotAllMetaRegionsOnlineException;
import org.apache.hadoop.hbase.exceptions.RestoreSnapshotException;
import org.apache.hadoop.hbase.exceptions.TableExistsException;
import org.apache.hadoop.hbase.master.MasterServices;
import org.apache.hadoop.hbase.master.SnapshotSentinel;
import org.apache.hadoop.hbase.master.handler.CreateTableHandler;
import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
import org.apache.hadoop.hbase.snapshot.ClientSnapshotDescriptionUtils;
import org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper;
import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;
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 volatile boolean stopped = false;
public CloneSnapshotHandler(final MasterServices masterServices,
final SnapshotDescription snapshot, final HTableDescriptor hTableDescriptor)
throws NotAllMetaRegionsOnlineException, TableExistsException, IOException {
super(masterServices, masterServices.getMasterFileSystem(), hTableDescriptor,
masterServices.getConfiguration(), null, masterServices);
// Snapshot information
this.snapshot = snapshot;
// Monitor
this.monitor = new ForeignExceptionDispatcher();
}
@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 META and do the assignment.
*/
@Override
protected List<HRegionInfo> handleCreateHdfsRegions(final Path tableRootDir, final String tableName)
throws IOException {
FileSystem fs = fileSystemManager.getFileSystem();
Path rootDir = fileSystemManager.getRootDir();
Path tableDir = new Path(tableRootDir, tableName);
try {
// 1. Execute the on-disk Clone
Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(snapshot, rootDir);
RestoreSnapshotHelper restoreHelper = new RestoreSnapshotHelper(conf, fs,
snapshot, snapshotDir, hTableDescriptor, tableDir, monitor);
RestoreSnapshotHelper.RestoreMetaChanges 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.
LOG.info("Clone snapshot=" + snapshot.getName() + " on table=" + tableName + " completed!");
// 2. let the CreateTableHandler add the regions to meta
return metaChanges.getRegionsToAdd();
} catch (Exception e) {
String msg = "clone snapshot=" + ClientSnapshotDescriptionUtils.toString(snapshot) + " failed";
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 completed(final Throwable exception) {
this.stopped = true;
super.completed(exception);
}
@Override
public boolean isFinished() {
return this.stopped;
}
@Override
public SnapshotDescription getSnapshot() {
return snapshot;
}
@Override
public void cancel(String why) {
if (this.stopped) return;
this.stopped = true;
LOG.info("Stopping clone snapshot=" + snapshot + " because: " + why);
this.monitor.receive(new ForeignException(NAME, new CancellationException(why)));
}
@Override
public ForeignException getExceptionIfFailed() {
return this.monitor.getException();
}
}