| /** |
| * 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.security; |
| |
| import java.io.IOException; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.CommonConfigurationKeys; |
| import org.apache.hadoop.util.ReflectionUtils; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| |
| /** |
| * A user-to-groups mapping service. |
| * |
| * {@link Groups} allows for server to get the various group memberships |
| * of a given user via the {@link #getGroups(String)} call, thus ensuring |
| * a consistent user-to-groups mapping and protects against vagaries of |
| * different mappings on servers and clients in a Hadoop cluster. |
| */ |
| @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"}) |
| @InterfaceStability.Evolving |
| public class Groups { |
| private static final Log LOG = LogFactory.getLog(Groups.class); |
| |
| private final GroupMappingServiceProvider impl; |
| |
| private final Map<String, CachedGroups> userToGroupsMap = |
| new ConcurrentHashMap<String, CachedGroups>(); |
| private final long cacheTimeout; |
| |
| public Groups(Configuration conf) { |
| impl = |
| ReflectionUtils.newInstance( |
| conf.getClass(CommonConfigurationKeys.HADOOP_SECURITY_GROUP_MAPPING, |
| ShellBasedUnixGroupsMapping.class, |
| GroupMappingServiceProvider.class), |
| conf); |
| |
| cacheTimeout = |
| conf.getLong(CommonConfigurationKeys.HADOOP_SECURITY_GROUPS_CACHE_SECS, 5*60) * 1000; |
| |
| LOG.info("Group mapping impl=" + impl.getClass().getName() + |
| "; cacheTimeout=" + cacheTimeout); |
| } |
| |
| /** |
| * Get the group memberships of a given user. |
| * @param user User's name |
| * @return the group memberships of the user |
| * @throws IOException |
| */ |
| public List<String> getGroups(String user) throws IOException { |
| // Return cached value if available |
| CachedGroups groups = userToGroupsMap.get(user); |
| long now = System.currentTimeMillis(); |
| // if cache has a value and it hasn't expired |
| if (groups != null && (groups.getTimestamp() + cacheTimeout > now)) { |
| LOG.debug("Returning cached groups for '" + user + "'"); |
| return groups.getGroups(); |
| } |
| |
| // Create and cache user's groups |
| groups = new CachedGroups(impl.getGroups(user)); |
| userToGroupsMap.put(user, groups); |
| LOG.debug("Returning fetched groups for '" + user + "'"); |
| return groups.getGroups(); |
| } |
| |
| /** |
| * Refresh all user-to-groups mappings. |
| */ |
| public void refresh() { |
| LOG.info("clearing userToGroupsMap cache"); |
| userToGroupsMap.clear(); |
| } |
| |
| private static class CachedGroups { |
| final long timestamp; |
| final List<String> groups; |
| |
| CachedGroups(List<String> groups) { |
| this.groups = groups; |
| this.timestamp = System.currentTimeMillis(); |
| } |
| |
| public long getTimestamp() { |
| return timestamp; |
| } |
| |
| public List<String> getGroups() { |
| return groups; |
| } |
| } |
| |
| private static Groups GROUPS = null; |
| |
| /** |
| * Get the groups being used to map user-to-groups. |
| * @return the groups being used to map user-to-groups. |
| */ |
| public static Groups getUserToGroupsMappingService(Configuration conf) { |
| if(GROUPS == null) { |
| LOG.debug(" Creating new Groups object"); |
| GROUPS = new Groups(conf); |
| } |
| return GROUPS; |
| } |
| } |