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