/**
* 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.URL;
import java.security.PrivilegedExceptionAction;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.DFSConfigKeys;
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.hdfs.protocol.HdfsFileStatus;
import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
import org.apache.hadoop.hdfs.server.common.JspHelper;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.util.ServletUtil;
/** Redirect queries about the hosted filesystem to an appropriate datanode.
* @see org.apache.hadoop.hdfs.HftpFileSystem
*/
@InterfaceAudience.Private
public class FileDataServlet extends DfsServlet {
/** For java.io.Serializable */
private static final long serialVersionUID = 1L;
/** Create a redirection URL */
private URL createRedirectURL(String path, String encodedPath, HdfsFileStatus status,
UserGroupInformation ugi, ClientProtocol nnproxy, HttpServletRequest request, String dt)
throws IOException {
String scheme = request.getScheme();
final LocatedBlocks blks = nnproxy.getBlockLocations(
status.getFullPath(new Path(path)).toUri().getPath(), 0, 1);
final Configuration conf = NameNodeHttpServer.getConfFromContext(
getServletContext());
final DatanodeID host = pickSrcDatanode(blks, status, conf);
final String hostname;
if (host instanceof DatanodeInfo) {
hostname = ((DatanodeInfo)host).getHostName();
} else {
hostname = host.getIpAddr();
}
int port = host.getInfoPort();
if ("https".equals(scheme)) {
final Integer portObject = (Integer) getServletContext().getAttribute(
DFSConfigKeys.DFS_DATANODE_HTTPS_PORT_KEY);
if (portObject != null) {
port = portObject;
}
}
String dtParam = "";
if (dt != null) {
dtParam=JspHelper.getDelegationTokenUrlParam(dt);
}
// Add namenode address to the url params
NameNode nn = NameNodeHttpServer.getNameNodeFromContext(
getServletContext());
String addr = nn.getNameNodeAddressHostPortString();
String addrParam = JspHelper.getUrlParam(JspHelper.NAMENODE_ADDRESS, addr);
return new URL(scheme, hostname, port,
"/streamFile" + encodedPath + '?' +
"ugi=" + ServletUtil.encodeQueryValue(ugi.getShortUserName()) +
dtParam + addrParam);
}
/** Select a datanode to service this request.
* Currently, this looks at no more than the first five blocks of a file,
* selecting a datanode randomly from the most represented.
* @param conf
*/
private DatanodeID pickSrcDatanode(LocatedBlocks blks, HdfsFileStatus i,
Configuration conf) throws IOException {
if (i.getLen() == 0 || blks.getLocatedBlocks().size() <= 0) {
// pick a random datanode
NameNode nn = NameNodeHttpServer.getNameNodeFromContext(
getServletContext());
return NamenodeJspHelper.getRandomDatanode(nn);
}
return JspHelper.bestNode(blks, conf);
}
/**
* Service a GET request as described below.
* Request:
* {@code
* GET http://<nn>:<port>/data[/<path>] HTTP/1.1
* }
*/
@Override
public void doGet(final HttpServletRequest request,
final HttpServletResponse response)
throws IOException {
final Configuration conf = NameNodeHttpServer.getConfFromContext(
getServletContext());
final UserGroupInformation ugi = getUGI(request, conf);
try {
ugi.doAs(new PrivilegedExceptionAction<Void>() {
@Override
public Void run() throws IOException {
ClientProtocol nn = createNameNodeProxy();
final String path = ServletUtil.getDecodedPath(request, "/data");
final String encodedPath = ServletUtil.getRawPath(request, "/data");
String delegationToken = request
.getParameter(JspHelper.DELEGATION_PARAMETER_NAME);
HdfsFileStatus info = nn.getFileInfo(path);
if (info != null && !info.isDir()) {
response.sendRedirect(createRedirectURL(path, encodedPath,
info, ugi, nn, request, delegationToken).toString());
} else if (info == null) {
response.sendError(400, "File not found " + path);
} else {
response.sendError(400, path + ": is a directory");
}
return null;
}
});
} catch (IOException e) {
response.sendError(400, e.getMessage());
} catch (InterruptedException e) {
response.sendError(400, e.getMessage());
}
}
}