/**
* 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.hive.ql.parse;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
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.hive.conf.HiveConf;
import org.apache.hadoop.hive.metastore.MetaStorePreEventListener;
import org.apache.hadoop.hive.metastore.Warehouse;
import org.apache.hadoop.hive.metastore.HiveMetaStore.HMSHandler;
import org.apache.hadoop.hive.metastore.api.InvalidOperationException;
import org.apache.hadoop.hive.metastore.api.MetaException;
import org.apache.hadoop.hive.metastore.api.NoSuchObjectException;
import org.apache.hadoop.hive.metastore.api.Table;
import org.apache.hadoop.hive.metastore.events.PreDropTableEvent;
import org.apache.hadoop.hive.metastore.events.PreEventContext;
import org.apache.hadoop.hive.metastore.events.PreEventContext.PreEventType;
import org.apache.hadoop.hive.ql.session.SessionState;
import org.apache.hadoop.hive.ql.parse.ImportSemanticAnalyzer;
/**
* This class listens for drop events and, if set, exports the table's metadata as JSON to the trash
* of the user performing the drop
*/
public class MetaDataExportListener extends MetaStorePreEventListener {
public static final Log LOG = LogFactory.getLog(MetaDataExportListener.class);
/** Configure the export listener */
public MetaDataExportListener(Configuration config) {
super(config);
}
/** Export the metadata to a given path, and then move it to the user's trash */
private void export_meta_data(PreDropTableEvent tableEvent) throws MetaException {
FileSystem fs = null;
Table tbl = tableEvent.getTable();
String name = tbl.getTableName();
org.apache.hadoop.hive.ql.metadata.Table mTbl = new org.apache.hadoop.hive.ql.metadata.Table(
tbl);
HMSHandler handler = tableEvent.getHandler();
HiveConf hiveconf = handler.getHiveConf();
Warehouse wh = new Warehouse(hiveconf);
Path tblPath = new Path(tbl.getSd().getLocation());
fs = wh.getFs(tblPath);
Date now = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");
String dateString = sdf.format(now);
String exportPathString = hiveconf.getVar(HiveConf.ConfVars.METADATA_EXPORT_LOCATION);
boolean moveMetadataToTrash = hiveconf
.getBoolVar(HiveConf.ConfVars.MOVE_EXPORTED_METADATA_TO_TRASH);
Path exportPath = null;
if (exportPathString != null && exportPathString.length() == 0) {
exportPath = fs.getHomeDirectory();
} else {
exportPath = new Path(exportPathString);
}
Path metaPath = new Path(exportPath, name + "." + dateString);
LOG.info("Exporting the metadata of table " + tbl.toString() + " to path "
+ metaPath.toString());
try {
fs.mkdirs(metaPath);
} catch (IOException e) {
throw new MetaException(e.getMessage());
}
Path outFile = new Path(metaPath, name + ImportSemanticAnalyzer.METADATA_NAME);
try {
SessionState.getConsole().printInfo("Beginning metadata export");
EximUtil.createExportDump(fs, outFile, mTbl, null);
if (moveMetadataToTrash == true) {
wh.deleteDir(metaPath, true);
}
} catch (IOException e) {
throw new MetaException(e.getMessage());
} catch (SemanticException e) {
throw new MetaException(e.getMessage());
}
}
/**
* Listen for an event; if it is a DROP_TABLE event, call export_meta_data
* */
@Override
public void onEvent(PreEventContext context) throws MetaException, NoSuchObjectException,
InvalidOperationException {
if (context.getEventType() == PreEventType.DROP_TABLE) {
export_meta_data((PreDropTableEvent) context);
}
}
}