org.apache.hadoop.hdfs.server.namenode.GetDelegationTokenServlet.java Source code

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Here is the source code for org.apache.hadoop.hdfs.server.namenode.GetDelegationTokenServlet.java

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/**
 * 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.DataOutputStream;
import java.io.IOException;
import java.security.PrivilegedExceptionAction;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
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.security.token.delegation.DelegationTokenIdentifier;
import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenSecretManager;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.security.Credentials;
import org.apache.hadoop.security.SecurityUtil;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.security.token.Token;

/**
 * Serve delegation tokens over http for use in hftp.
 */
@SuppressWarnings("serial")
public class GetDelegationTokenServlet extends DfsServlet {
    private static final Log LOG = LogFactory.getLog(GetDelegationTokenServlet.class);
    public static final String PATH_SPEC = "/getDelegationToken";
    public static final String RENEWER = "renewer";

    @Override
    protected void doGet(final HttpServletRequest req, final HttpServletResponse resp)
            throws ServletException, IOException {
        final UserGroupInformation ugi;
        final ServletContext context = getServletContext();
        final Configuration conf = (Configuration) context.getAttribute(JspHelper.CURRENT_CONF);
        try {
            ugi = getUGI(req, conf);
        } catch (IOException ioe) {
            LOG.info("Request for token received with no authentication from " + req.getRemoteAddr(), ioe);
            resp.sendError(HttpServletResponse.SC_FORBIDDEN, "Unable to identify or authenticate user");
            return;
        }
        LOG.info("Sending token: {" + ugi.getUserName() + "," + req.getRemoteAddr() + "}");
        final NameNode nn = (NameNode) context.getAttribute("name.node");
        String renewer = req.getParameter(RENEWER);
        final String renewerFinal = (renewer == null) ? req.getUserPrincipal().getName() : renewer;

        DataOutputStream dos = null;
        try {
            dos = new DataOutputStream(resp.getOutputStream());
            final DataOutputStream dosFinal = dos; // for doAs block
            ugi.doAs(new PrivilegedExceptionAction<Void>() {
                @Override
                public Void run() throws IOException {
                    final Credentials ts = DelegationTokenSecretManager.createCredentials(nn, ugi, renewerFinal);
                    ts.write(dosFinal);
                    dosFinal.close();
                    return null;
                }
            });

        } catch (Exception e) {
            LOG.info("Exception while sending token. Re-throwing. ", e);
            resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        } finally {
            if (dos != null)
                dos.close();
        }
    }
}