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 */ 018 019 package org.apache.hadoop.fs.http.server; 020 021 import org.apache.hadoop.conf.Configuration; 022 import org.apache.hadoop.fs.CommonConfigurationKeysPublic; 023 import org.apache.hadoop.lib.server.ServerException; 024 import org.apache.hadoop.lib.service.FileSystemAccess; 025 import org.apache.hadoop.lib.servlet.ServerWebApp; 026 import org.slf4j.Logger; 027 import org.slf4j.LoggerFactory; 028 029 import java.io.IOException; 030 031 /** 032 * Bootstrap class that manages the initialization and destruction of the 033 * HttpFSServer server, it is a <code>javax.servlet.ServletContextListener 034 * </code> implementation that is wired in HttpFSServer's WAR 035 * <code>WEB-INF/web.xml</code>. 036 * <p/> 037 * It provides acces to the server context via the singleton {@link #get}. 038 * <p/> 039 * All the configuration is loaded from configuration properties prefixed 040 * with <code>httpfs.</code>. 041 */ 042 public class HttpFSServerWebApp extends ServerWebApp { 043 private static final Logger LOG = 044 LoggerFactory.getLogger(HttpFSServerWebApp.class); 045 046 /** 047 * Server name and prefix for all configuration properties. 048 */ 049 public static final String NAME = "httpfs"; 050 051 /** 052 * Configuration property that defines HttpFSServer admin group. 053 */ 054 public static final String CONF_ADMIN_GROUP = "admin.group"; 055 056 private static HttpFSServerWebApp SERVER; 057 058 private String adminGroup; 059 060 /** 061 * Default constructor. 062 * 063 * @throws IOException thrown if the home/conf/log/temp directory paths 064 * could not be resolved. 065 */ 066 public HttpFSServerWebApp() throws IOException { 067 super(NAME); 068 } 069 070 /** 071 * Constructor used for testing purposes. 072 */ 073 protected HttpFSServerWebApp(String homeDir, String configDir, String logDir, 074 String tempDir, Configuration config) { 075 super(NAME, homeDir, configDir, logDir, tempDir, config); 076 } 077 078 /** 079 * Constructor used for testing purposes. 080 */ 081 public HttpFSServerWebApp(String homeDir, Configuration config) { 082 super(NAME, homeDir, config); 083 } 084 085 /** 086 * Initializes the HttpFSServer server, loads configuration and required 087 * services. 088 * 089 * @throws ServerException thrown if HttpFSServer server could not be 090 * initialized. 091 */ 092 @Override 093 public void init() throws ServerException { 094 super.init(); 095 if (SERVER != null) { 096 throw new RuntimeException("HttpFSServer server already initialized"); 097 } 098 SERVER = this; 099 adminGroup = getConfig().get(getPrefixedName(CONF_ADMIN_GROUP), "admin"); 100 LOG.info("Connects to Namenode [{}]", 101 get().get(FileSystemAccess.class).getFileSystemConfiguration(). 102 get(CommonConfigurationKeysPublic.FS_DEFAULT_NAME_KEY)); 103 } 104 105 /** 106 * Shutdowns all running services. 107 */ 108 @Override 109 public void destroy() { 110 SERVER = null; 111 super.destroy(); 112 } 113 114 /** 115 * Returns HttpFSServer server singleton, configuration and services are 116 * accessible through it. 117 * 118 * @return the HttpFSServer server singleton. 119 */ 120 public static HttpFSServerWebApp get() { 121 return SERVER; 122 } 123 124 /** 125 * Returns HttpFSServer admin group. 126 * 127 * @return httpfs admin group. 128 */ 129 public String getAdminGroup() { 130 return adminGroup; 131 } 132 133 }