/**
* 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.hdfs.server.namenode;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Enumeration;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hdfs.DFSClient;
import org.apache.hadoop.hdfs.protocol.ClientProtocol;
import org.apache.hadoop.hdfs.protocol.DatanodeID;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
import org.apache.hadoop.security.UnixUserGroupInformation;
import org.apache.hadoop.security.UserGroupInformation;
/**
* A base class for the servlets in DFS.
*/
abstract class DfsServlet extends HttpServlet {
/** For java.io.Serializable */
private static final long serialVersionUID = 1L;
static final Log LOG = LogFactory.getLog(DfsServlet.class.getCanonicalName());
/** Get {@link UserGroupInformation} from request */
protected UnixUserGroupInformation getUGI(HttpServletRequest request) {
String ugi = request.getParameter("ugi");
try {
return new UnixUserGroupInformation(ugi.split(","));
}
catch(Exception e) {
LOG.warn("Invalid ugi (= " + ugi + ")");
}
return JspHelper.webUGI;
}
/**
* Create a {@link NameNode} proxy from the current {@link ServletContext}.
*/
protected ClientProtocol createNameNodeProxy(UnixUserGroupInformation ugi
) throws IOException {
ServletContext context = getServletContext();
InetSocketAddress nnAddr = (InetSocketAddress)context.getAttribute("name.node.address");
if (nnAddr == null) {
throw new IOException("The namenode is not out of safemode yet");
}
Configuration conf = new Configuration(
(Configuration)context.getAttribute("name.conf"));
UnixUserGroupInformation.saveToConf(conf,
UnixUserGroupInformation.UGI_PROPERTY_NAME, ugi);
return DFSClient.createNamenode(nnAddr, conf);
}
/** Create a URI for redirecting request to a datanode */
protected URI createRedirectUri(String servletpath, UserGroupInformation ugi,
DatanodeID host, HttpServletRequest request, NameNode nn) throws URISyntaxException {
final String hostname = host instanceof DatanodeInfo?
((DatanodeInfo)host).getHostName(): host.getHost();
final String scheme = request.getScheme();
final int port = "https".equals(scheme)?
(Integer)getServletContext().getAttribute("datanode.https.port")
: host.getInfoPort();
// Add namenode address to the URL params
final String nnAddr = NameNode.getHostPortString(nn.getNameNodeAddress());
final String filename = request.getPathInfo();
return new URI(scheme, null, hostname, port, servletpath,
"filename=" + filename + "&ugi=" + ugi +
JspHelper.getUrlParam(JspHelper.NAMENODE_ADDRESS, nnAddr), null);
}
/** Get filename from the request */
protected String getFilename(HttpServletRequest request,
HttpServletResponse response) throws IOException {
final String filename = request.getParameter("filename");
if (filename == null || filename.length() == 0) {
throw new IOException("Invalid filename");
}
return filename;
}
/** Create a URI for streaming a file */
protected URI createUri(String file,
DatanodeID[] candidates, UnixUserGroupInformation ugi,
HttpServletRequest request) throws URISyntaxException {
String scheme = request.getScheme();
final DatanodeID host = candidates[0];
final String hostname;
if (host instanceof DatanodeInfo) {
hostname = ((DatanodeInfo)host).getHostName();
} else {
hostname = host.getHost();
}
// Construct query.
StringBuilder builder = new StringBuilder();
builder.append("ugi=" + ugi);
// Populate the rest of parameters.
Enumeration<?> it = request.getParameterNames();
while (it.hasMoreElements()) {
String key = it.nextElement().toString();
String value = request.getParameter(key);
builder.append("&" + key + "=" + value);
}
// Construct the possible candidates for retry
if (candidates.length > 1) {
builder.append("&candidates=");
appendDatanodeID(builder, candidates[1]);
for (int j=2; j<candidates.length; j++) {
builder.append(" ");
appendDatanodeID(builder, candidates[j]);
}
}
// Add namenode address to the url params
NameNode nn = (NameNode)getServletContext().getAttribute("name.node");
String addr = NameNode.getHostPortString(nn.getNameNodeAddress());
builder.append(JspHelper.getUrlParam(JspHelper.NAMENODE_ADDRESS, addr));
return new URI(scheme, null, hostname,
"https".equals(scheme)
? (Integer)getServletContext().getAttribute("datanode.https.port")
: host.getInfoPort(),
"/streamFile" + file, builder.toString(), null);
}
private static void appendDatanodeID(StringBuilder builder,
DatanodeID candidate) {
builder.append(candidate.getHost());
builder.append(":");
builder.append(candidate.getInfoPort());
}
}