| /** |
| * 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.URI; |
| import java.net.URISyntaxException; |
| import javax.servlet.http.HttpServletRequest; |
| import javax.servlet.http.HttpServletResponse; |
| |
| import org.apache.hadoop.fs.FileStatus; |
| 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.LocatedBlocks; |
| import org.apache.hadoop.hdfs.server.common.JspHelper; |
| import org.apache.hadoop.security.UnixUserGroupInformation; |
| |
| /** Redirect queries about the hosted filesystem to an appropriate datanode. |
| * @see org.apache.hadoop.hdfs.HftpFileSystem |
| */ |
| public class FileDataServlet extends DfsServlet { |
| /** For java.io.Serializable */ |
| private static final long serialVersionUID = 1L; |
| |
| /** Create a redirection URI */ |
| protected URI createUri(FileStatus i, UnixUserGroupInformation ugi, |
| ClientProtocol nnproxy, HttpServletRequest request) |
| throws IOException, URISyntaxException { |
| String scheme = request.getScheme(); |
| final DatanodeID host = pickSrcDatanode(i, nnproxy); |
| final String hostname; |
| if (host instanceof DatanodeInfo) { |
| hostname = ((DatanodeInfo)host).getHostName(); |
| } else { |
| hostname = host.getHost(); |
| } |
| return new URI(scheme, null, hostname, |
| "https".equals(scheme) |
| ? (Integer)getServletContext().getAttribute("datanode.https.port") |
| : host.getInfoPort(), |
| "/streamFile", "filename=" + i.getPath() + "&ugi=" + ugi, null); |
| } |
| |
| /** 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. |
| */ |
| private DatanodeID pickSrcDatanode(FileStatus i, |
| ClientProtocol nnproxy) throws IOException { |
| final LocatedBlocks blks = nnproxy.getBlockLocations( |
| i.getPath().toUri().getPath(), 0, 1); |
| if (i.getLen() == 0 || blks.getLocatedBlocks().size() <= 0) { |
| // pick a random datanode |
| NameNode nn = (NameNode)getServletContext().getAttribute("name.node"); |
| return nn.getNamesystem().getRandomDatanode(); |
| } |
| return JspHelper.bestNode(blks.get(0)); |
| } |
| |
| /** |
| * Service a GET request as described below. |
| * Request: |
| * {@code |
| * GET http://<nn>:<port>/data[/<path>] HTTP/1.1 |
| * } |
| */ |
| public void doGet(HttpServletRequest request, HttpServletResponse response) |
| throws IOException { |
| final UnixUserGroupInformation ugi = getUGI(request); |
| final ClientProtocol nnproxy = createNameNodeProxy(ugi); |
| |
| try { |
| final String path = request.getPathInfo() != null |
| ? request.getPathInfo() : "/"; |
| FileStatus info = nnproxy.getFileInfo(path); |
| if ((info != null) && !info.isDir()) { |
| response.sendRedirect(createUri(info, ugi, nnproxy, |
| request).toURL().toString()); |
| } else if (info == null){ |
| response.sendError(400, "cat: File not found " + path); |
| } else { |
| response.sendError(400, "cat: " + path + ": is a directory"); |
| } |
| } catch (URISyntaxException e) { |
| response.getWriter().println(e.toString()); |
| } catch (IOException e) { |
| response.sendError(400, e.getMessage()); |
| } |
| } |
| |
| } |
| |