| /* |
| * 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.yarn.service.utils; |
| |
| import org.apache.hadoop.registry.client.binding.RegistryUtils; |
| import org.apache.hadoop.yarn.service.conf.YarnServiceConstants; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import javax.naming.Context; |
| import javax.naming.NameNotFoundException; |
| import javax.naming.NamingException; |
| import javax.naming.directory.Attributes; |
| import javax.naming.directory.DirContext; |
| import javax.naming.directory.InitialDirContext; |
| import java.net.InetAddress; |
| import java.net.UnknownHostException; |
| import java.util.Hashtable; |
| |
| |
| public class ServiceRegistryUtils { |
| private static final Logger LOG = |
| LoggerFactory.getLogger(ServiceRegistryUtils.class); |
| |
| public static final String SVC_USERS = "/services/yarn/users"; |
| |
| /** |
| * Get the registry path for an instance under the user's home node |
| * @param instanceName application instance |
| * @return a path to the registry location for this application instance. |
| */ |
| public static String registryPathForInstance(String instanceName) { |
| return RegistryUtils.servicePath( |
| RegistryUtils.currentUser(), YarnServiceConstants.APP_TYPE, instanceName |
| ); |
| } |
| |
| /** |
| * Build the path to a service folder |
| * @param username user name |
| * @param serviceName service name |
| * @return the home path to the service |
| */ |
| public static String mkServiceHomePath(String username, String serviceName) { |
| return mkUserHomePath(username) + "/" + serviceName; |
| } |
| |
| /** |
| * Build the path to a user home folder; |
| */ |
| public static String mkUserHomePath(String username) { |
| return SVC_USERS + "/" + username; |
| } |
| |
| /** |
| * Determine whether a DNS lookup exists for a given name. If a DNS server |
| * address is provided, the lookup will be performed against this DNS |
| * server. This option is provided because it may be desirable to perform |
| * the lookup against Registry DNS directly to avoid caching of negative |
| * responses that may be performed by other DNS servers, thereby allowing the |
| * lookup to succeed sooner. |
| * |
| * @param addr host:port dns address, or null |
| * @param name name to look up |
| * @return true if a lookup succeeds for the specified name |
| */ |
| public static boolean registryDNSLookupExists(String addr, String |
| name) { |
| if (addr == null) { |
| try { |
| InetAddress.getByName(name); |
| return true; |
| } catch (UnknownHostException e) { |
| return false; |
| } |
| } |
| |
| String dnsURI = String.format("dns://%s", addr); |
| Hashtable<String, Object> env = new Hashtable<>(); |
| env.put(Context.INITIAL_CONTEXT_FACTORY, |
| "com.sun.jndi.dns.DnsContextFactory"); |
| env.put(Context.PROVIDER_URL, dnsURI); |
| |
| try { |
| DirContext ictx = new InitialDirContext(env); |
| Attributes attrs = ictx.getAttributes(name, new String[]{"A"}); |
| |
| if (attrs.size() > 0) { |
| return true; |
| } |
| } catch (NameNotFoundException e) { |
| // this doesn't need to be logged |
| } catch (NamingException e) { |
| LOG.error("Got exception when performing DNS lookup", e); |
| } |
| |
| return false; |
| } |
| |
| } |