hadoop ServiceRegistryUtils 源码

haddop ServiceRegistryUtils 代码

文件路径：/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-applications/hadoop-yarn-services/hadoop-yarn-services-core/src/main/java/org/apache/hadoop/yarn/service/utils/ServiceRegistryUtils.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.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;
  }

}

相关信息

hadoop 源码目录

相关文章

hadoop ApplicationReportSerDeser 源码

hadoop ClientRegistryBinder 源码

hadoop Comparators 源码

hadoop ConfigHelper 源码

hadoop ConfigUtils 源码

hadoop CoreFileSystem 源码

hadoop Duration 源码

hadoop FilterUtils 源码

hadoop HttpUtil 源码

hadoop JsonSerDeser 源码