/**
    *
    * 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.hbase.util;
  
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.net.URL;
  import java.util.Map;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.http.HttpServer;
  import org.mortbay.jetty.handler.ContextHandlerCollection;
  import org.mortbay.jetty.servlet.Context;
  import org.mortbay.jetty.servlet.DefaultServlet;
  
  /**
   * Create a Jetty embedded server to answer http requests. The primary goal
   * is to serve up status information for the server.
   * There are three contexts:
   *   "/stacks/" -> points to stack trace
   *   "/static/" -> points to common static files (src/hbase-webapps/static)
   *   "/" -> the jsp server code from (src/hbase-webapps/<name>)
   */
  @InterfaceAudience.Private
  public class InfoServer extends HttpServer {
    private final Configuration config;
  
    /**
     * Create a status server on the given port.
     * The jsp scripts are taken from src/hbase-webapps/<code>name<code>.
     * @param name The name of the server
     * @param bindAddress address to bind to
     * @param port The port to use on the server
     * @param findPort whether the server should start at the given port and
     * increment by 1 until it finds a free port.
     * @throws IOException e
     */
    public InfoServer(String name, String bindAddress, int port, boolean findPort,
        final Configuration c)
    throws IOException {
      super(name, bindAddress, port, findPort, c);
      this.config = c;
      fixupLogsServletLocation();
    }
  
    /**
     * Fixup where the logs app points, make it point at hbase logs rather than
     * hadoop logs.
     */
    private void fixupLogsServletLocation() {
      // Must be same as up in hadoop.
      final String logsContextPath = "/logs";
      // Now, put my logs in place of hadoops... disable old one first.
      Context oldLogsContext = null;
      for (Map.Entry<Context, Boolean> e : defaultContexts.entrySet()) {
        if (e.getKey().getContextPath().equals(logsContextPath)) {
          oldLogsContext = e.getKey();
          break;
        }
      }
      if (oldLogsContext != null) {
        this.defaultContexts.put(oldLogsContext, Boolean.FALSE);
      }
      // Now do my logs.
      // Set up the context for "/logs/" if "hbase.log.dir" property is defined.
      String logDir = System.getProperty("hbase.log.dir");
      if (logDir != null) {
        // This is a little presumptious but seems to work.
        Context logContext =
          new Context((ContextHandlerCollection)this.webServer.getHandler(),
            logsContextPath);
        logContext.setResourceBase(logDir);
        logContext.addServlet(DefaultServlet.class, "/");
        HttpServerUtil.constrainHttpMethods(logContext);
        defaultContexts.put(logContext, true);
      }
    }
  
    /**
     * Get the pathname to the webapps files.
     * @param appName eg "secondary" or "datanode"
    * @return the pathname as a URL
    * @throws FileNotFoundException if 'webapps' directory cannot be found on CLASSPATH.
    */
   protected String getWebAppsPath(String appName) throws FileNotFoundException {
     // Copied from the super-class.
     String resourceName = "hbase-webapps/" + appName;
     URL url = getClass().getClassLoader().getResource(resourceName);
     if (url == null)
       throw new FileNotFoundException(resourceName + " not found in CLASSPATH");
     String urlString = url.toString();
     return urlString.substring(0, urlString.lastIndexOf('/'));
   }
 
   /**
    * Get the pathname to the <code>path</code> files.
    * @return the pathname as a URL
    */
   protected String getWebAppsPath() throws IOException {
     // Hack: webapps is not a unique enough element to find in CLASSPATH
     // We'll more than likely find the hadoop webapps dir.  So, instead
     // look for the 'master' webapp in the webapps subdir.  That should
     // get us the hbase context.  Presumption is that place where the
     // master webapp resides is where we want this InfoServer picking up
     // web applications.
     final String master = "master";
     String p = getWebAppsPath(master);
     // Now strip master off the end if it is present
     if(p.endsWith(master)) {
       return p.substring(0, p.lastIndexOf(master));
     }
     return p;
   }
 }