Ethanlm commented on a change in pull request #3112: [STORM-3494] use HdfsLoginUtil singleton to login to hdfs URL: https://github.com/apache/storm/pull/3112#discussion_r316850716
########## File path: storm-client/src/jvm/org/apache/storm/utils/HdfsLoginUtil.java ########## @@ -0,0 +1,81 @@ +/* + * 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.storm.utils; + +import java.util.Map; +import javax.security.auth.Subject; +import org.apache.storm.Config; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Use this class only to login to HDFS from storm servers. + */ +public class HdfsLoginUtil { + + private static final Logger LOG = LoggerFactory.getLogger(HdfsLoginUtil.class); + + private static HdfsLoginUtil singleton; + + private IHdfsLoginPlugin hdfsLoginPlugin; + + private HdfsLoginUtil() { + // private constructor + } + + /** + * Get the singleton instance. + * @return the singleton instance + */ + public static HdfsLoginUtil getInstance() { + if (singleton == null) { + synchronized (HdfsLoginUtil.class) { + if (singleton == null) { + singleton = new HdfsLoginUtil(); + } + } + } + return singleton; + } + + /** + * Login to hdfs. + * We use the single HdfsLoginPlugin instance because it may use some local state/cache. + * @param conf the storm configuration + * @return the logged in subject + */ + public Subject logintoHdfs(Map<String, Object> conf) { + + if (hdfsLoginPlugin == null) { + synchronized (HdfsLoginUtil.class) { + if (hdfsLoginPlugin == null) { + String className = (String) conf.get(Config.STORM_HDFS_LOGIN_PLUGIN); Review comment: We will then introduce hdfs dependencies to `storm-client`. I think (but I am not sure) it's also part of the reason that we separate storm-hdfs-blobstore out. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
