/**
* Copyright 2013 Cloudera Inc.
*
* Licensed 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 com.cloudera.cdk.data.hcatalog;
import com.cloudera.cdk.data.DatasetDescriptor;
import com.cloudera.cdk.data.DatasetExistsException;
import com.cloudera.cdk.data.MetadataProviderException;
import com.cloudera.cdk.data.filesystem.impl.Accessor;
import com.google.common.base.Preconditions;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hive.metastore.TableType;
import org.apache.hadoop.hive.ql.metadata.Table;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
class HCatalogExternalMetadataProvider extends HCatalogMetadataProvider {
private static final Logger logger = LoggerFactory
.getLogger(HCatalogExternalMetadataProvider.class);
private final Path rootDirectory;
private final FileSystem rootFileSystem;
public HCatalogExternalMetadataProvider(Configuration conf, Path rootDirectory) {
super(conf);
Preconditions.checkArgument(rootDirectory != null, "Root cannot be null");
try {
this.rootFileSystem = rootDirectory.getFileSystem(conf);
this.rootDirectory = rootFileSystem.makeQualified(rootDirectory);
} catch (IOException ex) {
throw new MetadataProviderException(
"Could not get FileSystem for root path", ex);
}
}
@Override
public DatasetDescriptor load(String name) {
Preconditions.checkArgument(name != null, "Name cannot be null");
final Table table = hcat.getTable(HiveUtils.DEFAULT_DB, name);
if (!TableType.EXTERNAL_TABLE.equals(table.getTableType())) {
throw new MetadataProviderException(
"Table is not external, type:" + table.getTableType());
}
return HiveUtils.descriptorForTable(conf, table);
}
@Override
public DatasetDescriptor create(String name, DatasetDescriptor descriptor) {
Preconditions.checkArgument(name != null, "Name cannot be null");
Preconditions.checkArgument(descriptor != null,
"Descriptor cannot be null");
if (exists(name)) {
throw new DatasetExistsException(
"Metadata already exists for dataset:" + name);
}
logger.info("Creating an external Hive table named: " + name);
// create a new descriptor with the dataset's location
final DatasetDescriptor newDescriptor =
new DatasetDescriptor.Builder(descriptor)
.location(pathForDataset(name))
.build();
// create the data directory first so it is owned by the current user, not Hive
Accessor.getDefault().ensureExists(newDescriptor, conf);
// this object will be the table metadata
final Table table = HiveUtils.tableForDescriptor(
name, newDescriptor, true /* external table */ );
// assign the location of the the table
hcat.createTable(table);
return newDescriptor;
}
private Path pathForDataset(String name) {
Preconditions.checkState(rootDirectory != null,
"Dataset repository root directory can not be null");
return rootFileSystem.makeQualified(
HiveUtils.pathForDataset(rootDirectory, name));
}
}