001/** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019package org.apache.hadoop.fs.http.server; 020 021import org.apache.hadoop.classification.InterfaceAudience; 022import org.apache.hadoop.conf.Configuration; 023import org.apache.hadoop.fs.CommonConfigurationKeysPublic; 024import org.apache.hadoop.lib.server.ServerException; 025import org.apache.hadoop.lib.service.FileSystemAccess; 026import org.apache.hadoop.lib.servlet.ServerWebApp; 027import org.slf4j.Logger; 028import org.slf4j.LoggerFactory; 029 030import java.io.IOException; 031 032/** 033 * Bootstrap class that manages the initialization and destruction of the 034 * HttpFSServer server, it is a <code>javax.servlet.ServletContextListener 035 * </code> implementation that is wired in HttpFSServer's WAR 036 * <code>WEB-INF/web.xml</code>. 037 * <p/> 038 * It provides acces to the server context via the singleton {@link #get}. 039 * <p/> 040 * All the configuration is loaded from configuration properties prefixed 041 * with <code>httpfs.</code>. 042 */ 043@InterfaceAudience.Private 044public class HttpFSServerWebApp extends ServerWebApp { 045 private static final Logger LOG = 046 LoggerFactory.getLogger(HttpFSServerWebApp.class); 047 048 /** 049 * Server name and prefix for all configuration properties. 050 */ 051 public static final String NAME = "httpfs"; 052 053 /** 054 * Configuration property that defines HttpFSServer admin group. 055 */ 056 public static final String CONF_ADMIN_GROUP = "admin.group"; 057 058 private static HttpFSServerWebApp SERVER; 059 060 private String adminGroup; 061 062 /** 063 * Default constructor. 064 * 065 * @throws IOException thrown if the home/conf/log/temp directory paths 066 * could not be resolved. 067 */ 068 public HttpFSServerWebApp() throws IOException { 069 super(NAME); 070 } 071 072 /** 073 * Constructor used for testing purposes. 074 */ 075 public HttpFSServerWebApp(String homeDir, String configDir, String logDir, 076 String tempDir, Configuration config) { 077 super(NAME, homeDir, configDir, logDir, tempDir, config); 078 } 079 080 /** 081 * Constructor used for testing purposes. 082 */ 083 public HttpFSServerWebApp(String homeDir, Configuration config) { 084 super(NAME, homeDir, config); 085 } 086 087 /** 088 * Initializes the HttpFSServer server, loads configuration and required 089 * services. 090 * 091 * @throws ServerException thrown if HttpFSServer server could not be 092 * initialized. 093 */ 094 @Override 095 public void init() throws ServerException { 096 if (SERVER != null) { 097 throw new RuntimeException("HttpFSServer server already initialized"); 098 } 099 SERVER = this; 100 super.init(); 101 adminGroup = getConfig().get(getPrefixedName(CONF_ADMIN_GROUP), "admin"); 102 LOG.info("Connects to Namenode [{}]", 103 get().get(FileSystemAccess.class).getFileSystemConfiguration(). 104 get(CommonConfigurationKeysPublic.FS_DEFAULT_NAME_KEY)); 105 } 106 107 /** 108 * Shutdowns all running services. 109 */ 110 @Override 111 public void destroy() { 112 SERVER = null; 113 super.destroy(); 114 } 115 116 /** 117 * Returns HttpFSServer server singleton, configuration and services are 118 * accessible through it. 119 * 120 * @return the HttpFSServer server singleton. 121 */ 122 public static HttpFSServerWebApp get() { 123 return SERVER; 124 } 125 126 /** 127 * Returns HttpFSServer admin group. 128 * 129 * @return httpfs admin group. 130 */ 131 public String getAdminGroup() { 132 return adminGroup; 133 } 134 135}