/**
* 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.lib.servlet;
import com.google.common.annotations.VisibleForTesting;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.lib.server.Server;
import org.apache.hadoop.lib.server.ServerException;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.text.MessageFormat;
/**
* {@link Server} subclass that implements <code>ServletContextListener</code>
* and uses its lifecycle to start and stop the server.
*/
@InterfaceAudience.Private
public abstract class ServerWebApp extends Server implements ServletContextListener {
private static final String HOME_DIR = ".home.dir";
private static final String CONFIG_DIR = ".config.dir";
private static final String LOG_DIR = ".log.dir";
private static final String TEMP_DIR = ".temp.dir";
private static final String HTTP_HOSTNAME = ".http.hostname";
private static final String HTTP_PORT = ".http.port";
private static ThreadLocal<String> HOME_DIR_TL = new ThreadLocal<String>();
private InetSocketAddress authority;
/**
* Method for testing purposes.
*/
public static void setHomeDirForCurrentThread(String homeDir) {
HOME_DIR_TL.set(homeDir);
}
/**
* Constructor for testing purposes.
*/
protected ServerWebApp(String name, String homeDir, String configDir, String logDir, String tempDir,
Configuration config) {
super(name, homeDir, configDir, logDir, tempDir, config);
}
/**
* Constructor for testing purposes.
*/
protected ServerWebApp(String name, String homeDir, Configuration config) {
super(name, homeDir, config);
}
/**
* Constructor. Subclasses must have a default constructor specifying
* the server name.
* <p/>
* The server name is used to resolve the Java System properties that define
* the server home, config, log and temp directories.
* <p/>
* The home directory is looked in the Java System property
* <code>#SERVER_NAME#.home.dir</code>.
* <p/>
* The config directory is looked in the Java System property
* <code>#SERVER_NAME#.config.dir</code>, if not defined it resolves to
* the <code>#SERVER_HOME_DIR#/conf</code> directory.
* <p/>
* The log directory is looked in the Java System property
* <code>#SERVER_NAME#.log.dir</code>, if not defined it resolves to
* the <code>#SERVER_HOME_DIR#/log</code> directory.
* <p/>
* The temp directory is looked in the Java System property
* <code>#SERVER_NAME#.temp.dir</code>, if not defined it resolves to
* the <code>#SERVER_HOME_DIR#/temp</code> directory.
*
* @param name server name.
*/
public ServerWebApp(String name) {
super(name, getHomeDir(name),
getDir(name, CONFIG_DIR, getHomeDir(name) + "/conf"),
getDir(name, LOG_DIR, getHomeDir(name) + "/log"),
getDir(name, TEMP_DIR, getHomeDir(name) + "/temp"), null);
}
/**
* Returns the server home directory.
* <p/>
* It is looked up in the Java System property
* <code>#SERVER_NAME#.home.dir</code>.
*
* @param name the server home directory.
*
* @return the server home directory.
*/
static String getHomeDir(String name) {
String homeDir = HOME_DIR_TL.get();
if (homeDir == null) {
String sysProp = name + HOME_DIR;
homeDir = System.getProperty(sysProp);
if (homeDir == null) {
throw new IllegalArgumentException(MessageFormat.format("System property [{0}] not defined", sysProp));
}
}
return homeDir;
}
/**
* Convenience method that looks for Java System property defining a
* diretory and if not present defaults to the specified directory.
*
* @param name server name, used as prefix of the Java System property.
* @param dirType dir type, use as postfix of the Java System property.
* @param defaultDir the default directory to return if the Java System
* property <code>name + dirType</code> is not defined.
*
* @return the directory defined in the Java System property or the
* the default directory if the Java System property is not defined.
*/
static String getDir(String name, String dirType, String defaultDir) {
String sysProp = name + dirType;
return System.getProperty(sysProp, defaultDir);
}
/**
* Initializes the <code>ServletContextListener</code> which initializes
* the Server.
*
* @param event servelt context event.
*/
@Override
public void contextInitialized(ServletContextEvent event) {
try {
init();
} catch (ServerException ex) {
event.getServletContext().log("ERROR: " + ex.getMessage());
throw new RuntimeException(ex);
}
}
/**
* Resolves the host & port InetSocketAddress the web server is listening to.
* <p/>
* This implementation looks for the following 2 properties:
* <ul>
* <li>#SERVER_NAME#.http.hostname</li>
* <li>#SERVER_NAME#.http.port</li>
* </ul>
*
* @return the host & port InetSocketAddress the web server is listening to.
* @throws ServerException thrown if any of the above 2 properties is not defined.
*/
protected InetSocketAddress resolveAuthority() throws ServerException {
String hostnameKey = getName() + HTTP_HOSTNAME;
String portKey = getName() + HTTP_PORT;
String host = System.getProperty(hostnameKey);
String port = System.getProperty(portKey);
if (host == null) {
throw new ServerException(ServerException.ERROR.S13, hostnameKey);
}
if (port == null) {
throw new ServerException(ServerException.ERROR.S13, portKey);
}
try {
InetAddress add = InetAddress.getByName(host);
int portNum = Integer.parseInt(port);
return new InetSocketAddress(add, portNum);
} catch (UnknownHostException ex) {
throw new ServerException(ServerException.ERROR.S14, ex.toString(), ex);
}
}
/**
* Destroys the <code>ServletContextListener</code> which destroys
* the Server.
*
* @param event servelt context event.
*/
@Override
public void contextDestroyed(ServletContextEvent event) {
destroy();
}
/**
* Returns the hostname:port InetSocketAddress the webserver is listening to.
*
* @return the hostname:port InetSocketAddress the webserver is listening to.
*/
public InetSocketAddress getAuthority() throws ServerException {
synchronized (this) {
if (authority == null) {
authority = resolveAuthority();
}
}
return authority;
}
/**
* Sets an alternate hostname:port InetSocketAddress to use.
* <p/>
* For testing purposes.
*
* @param authority alterante authority.
*/
@VisibleForTesting
public void setAuthority(InetSocketAddress authority) {
this.authority = authority;
}
}