HiveConnectionMgr.java

/*
 * 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.ranger.services.hive.client;

import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.TimeUnit;

import org.apache.log4j.Logger;
import org.apache.ranger.plugin.util.TimedEventUtil;


public class HiveConnectionMgr {

	private static final Logger LOG = Logger.getLogger(HiveConnectionMgr.class);
	
	protected ConcurrentMap<String, HiveClient> 	hiveConnectionCache;
	protected ConcurrentMap<String, Boolean> 		repoConnectStatusMap;


	 public	HiveConnectionMgr() {
		 hiveConnectionCache = new ConcurrentHashMap<String, HiveClient>();
		 repoConnectStatusMap = new ConcurrentHashMap<String, Boolean>();
	 }
	

	 public HiveClient getHiveConnection(final String serviceName, final String serviceType, final Map<String,String> configs) {
			HiveClient hiveClient  = null;
			
			if (serviceType != null) {
				// get it from the cache
				hiveClient = hiveConnectionCache.get(serviceName);
				if (hiveClient == null) {
					if (configs != null) {
					
						final Callable<HiveClient> connectHive = new Callable<HiveClient>() {
							@Override
							public HiveClient call() throws Exception {
								return new HiveClient(serviceName, configs);
							}
						};
						try {
							hiveClient = TimedEventUtil.timedTask(connectHive, 5, TimeUnit.SECONDS);
						} catch(Exception e){
							LOG.error("Error connecting hive repository : "+
									serviceName +" using config : "+ configs, e);
						}

						HiveClient oldClient = null;
						if (hiveClient != null) {
							oldClient = hiveConnectionCache.putIfAbsent(serviceName, hiveClient);
						} else {
							oldClient = hiveConnectionCache.get(serviceName);
						}

						if (oldClient != null) {
							// in the meantime someone else has put a valid client into the cache, let's use that instead.
							if (hiveClient != null) {
								hiveClient.close();
							}
							hiveClient = oldClient;
						}
						repoConnectStatusMap.put(serviceName, true);
					} else {
						LOG.error("Connection Config not defined for asset :"
								+ serviceName, new Throwable());
					}
				} else {
					try {
						hiveClient.getDatabaseList("*",null);
					} catch(Exception e) {
						hiveConnectionCache.remove(serviceName);
						/*
						 * There is a possibility that some other thread is also using this connection that we are going to close but
						 * presumably the connection is bad which is why we are closing it, so damage should not be much.
						 */
						hiveClient.close();
						hiveClient = getHiveConnection(serviceName,serviceType,configs);
					}
				}
			} else {
				LOG.error("Asset not found with name "+serviceName, new Throwable());
			}
			return hiveClient;
		}
}