/**
* 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.zookeeper.server.admin;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.zookeeper.server.ZooKeeperServer;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletHolder;
import org.eclipse.jetty.server.ServerConnector;
import org.eclipse.jetty.servlet.ServletContextHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This class encapsulates a Jetty server for running Commands.
*
* Given the default settings, start a ZooKeeper server and visit
* http://<hostname>:8080/commands for links to all registered commands. Visiting
* http://<hostname>:8080/commands/<commandname> will execute the associated
* Command and return the result in the body of the response. Any keyword
* arguments to the command are specified with URL parameters (e.g.,
* http://localhost:8080/commands/set_trace_mask?traceMask=306).
*
* @see Commands
* @see CommandOutputter
*/
public class JettyAdminServer implements AdminServer {
static final Logger LOG = LoggerFactory.getLogger(JettyAdminServer.class);
public static final int DEFAULT_PORT = 8080;
public static final int DEFAULT_IDLE_TIMEOUT = 30000;
public static final String DEFAULT_COMMAND_URL = "/commands";
private static final String DEFAULT_ADDRESS = "0.0.0.0";
private final Server server;
private final String address;
private final int port;
private final int idleTimeout;
private final String commandUrl;
private ZooKeeperServer zkServer;
public JettyAdminServer() throws AdminServerException {
this(System.getProperty("zookeeper.admin.serverAddress", DEFAULT_ADDRESS),
Integer.getInteger("zookeeper.admin.serverPort", DEFAULT_PORT),
Integer.getInteger("zookeeper.admin.idleTimeout", DEFAULT_IDLE_TIMEOUT),
System.getProperty("zookeeper.admin.commandURL", DEFAULT_COMMAND_URL));
}
public JettyAdminServer(String address, int port, int timeout, String commandUrl) {
this.port = port;
this.idleTimeout = timeout;
this.commandUrl = commandUrl;
this.address = address;
server = new Server();
ServerConnector connector = new ServerConnector(server);
connector.setHost(address);
connector.setPort(port);
connector.setIdleTimeout(idleTimeout);
server.addConnector(connector);
ServletContextHandler context = new ServletContextHandler(ServletContextHandler.SESSIONS);
context.setContextPath("/*");
server.setHandler(context);
context.addServlet(new ServletHolder(new CommandServlet()), commandUrl + "/*");
}
/**
* Start the embedded Jetty server.
*/
@Override
public void start() throws AdminServerException {
try {
server.start();
} catch (Exception e) {
// Server.start() only throws Exception, so let's at least wrap it
// in an identifiable subclass
throw new AdminServerException(String.format(
"Problem starting AdminServer on address %s,"
+ " port %d and command URL %s", address, port,
commandUrl), e);
}
LOG.info(String.format("Started AdminServer on address %s, port %d"
+ " and command URL %s", address, port, commandUrl));
}
/**
* Stop the embedded Jetty server.
*
* This is not very important except for tests where multiple
* JettyAdminServers are started and may try to bind to the same ports if
* previous servers aren't shut down.
*/
@Override
public void shutdown() throws AdminServerException {
try {
server.stop();
} catch (Exception e) {
throw new AdminServerException(String.format(
"Problem stopping AdminServer on address %s,"
+ " port %d and command URL %s", address, port, commandUrl),
e);
}
}
/**
* Set the ZooKeeperServer that will be used to run Commands.
*
* It is not necessary to set the ZK server before calling
* AdminServer.start(), and the ZK server can be set to null when, e.g.,
* that server is being shut down. If the ZK server is not set or set to
* null, the AdminServer will still be able to issue Commands, but they will
* return an error until a ZK server is set.
*/
@Override
public void setZooKeeperServer(ZooKeeperServer zkServer) {
this.zkServer = zkServer;
}
private class CommandServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Capture the command name from the URL
String cmd = request.getPathInfo();
if (cmd == null || cmd.equals("/")) {
// No command specified, print links to all commands instead
for (String link : commandLinks()) {
response.getWriter().println(link);
response.getWriter().println("<br/>");
}
return;
}
// Strip leading "/"
cmd = cmd.substring(1);
// Extract keyword arguments to command from request parameters
@SuppressWarnings("unchecked")
Map<String, String[]> parameterMap = request.getParameterMap();
Map<String, String> kwargs = new HashMap<String, String>();
for (Map.Entry<String, String[]> entry : parameterMap.entrySet()) {
kwargs.put(entry.getKey(), entry.getValue()[0]);
}
// Run the command
CommandResponse cmdResponse = Commands.runCommand(cmd, zkServer, kwargs);
// Format and print the output of the command
CommandOutputter outputter = new JsonOutputter();
response.setStatus(HttpServletResponse.SC_OK);
response.setContentType(outputter.getContentType());
outputter.output(cmdResponse, response.getWriter());
}
}
/**
* Returns a list of URLs to each registered Command.
*/
private List<String> commandLinks() {
List<String> links = new ArrayList<String>();
List<String> commands = new ArrayList<String>(Commands.getPrimaryNames());
Collections.sort(commands);
for (String command : commands) {
String url = commandUrl + "/" + command;
links.add(String.format("<a href=\"%s\">%s</a>", url, command));
}
return links;
}
}