/*
 * Copyright 2011 LinkedIn, Inc
 *
 * Licensed 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 azkaban.jobExecutor;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.security.token.delegation.DelegationTokenIdentifier;
import org.apache.hadoop.security.token.Token;
import org.apache.log4j.Logger;

import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.security.PrivilegedExceptionAction;
import java.util.Properties;

import static azkaban.jobExecutor.utils.SecurityUtils.getProxiedUser;

public class SecurePigWrapper {

  public static final String OBTAIN_BINARY_TOKEN = "obtain.binary.token";
  public static final String MAPREDUCE_JOB_CREDENTIALS_BINARY = "mapreduce.job.credentials.binary";

  public static void main(final String[] args) throws IOException, InterruptedException {
    final Logger logger = Logger.getRootLogger();
    final Properties p = System.getProperties();
    final Configuration conf = new Configuration();

    getProxiedUser(p, logger, conf).doAs(new PrivilegedExceptionAction<Void>() {
      @Override
      public Void run() throws Exception {
        prefetchToken();
        org.apache.pig.Main.main(args);
        return null;
      }

      // For Pig jobs that need to do extra communication with the JobTracker,
      // it's necessary to pre-fetch a token and include it in the credentials
      // cache
      private void prefetchToken() throws InterruptedException, IOException {
        String shouldPrefetch = p.getProperty(OBTAIN_BINARY_TOKEN);
        if(shouldPrefetch != null && shouldPrefetch.equals("true") ) {
          logger.info("Pre-fetching token");
          Job job = new Job(conf, "totally phony, extremely fake, not real job");

          JobConf jc = new JobConf(conf);
          JobClient jobClient = new JobClient(jc);
          logger.info("Pre-fetching: Got new JobClient: " + jc);
          Token<DelegationTokenIdentifier> mrdt = jobClient.getDelegationToken(new Text("hi"));
          job.getCredentials().addToken(new Text("howdy"), mrdt);

          File temp = File.createTempFile("mr-azkaban", ".token");
          temp.deleteOnExit();

          FileOutputStream fos = null;
          DataOutputStream dos = null;
          try {
            fos = new FileOutputStream(temp);
            dos = new DataOutputStream(fos);
            job.getCredentials().writeTokenStorageToStream(dos);
          } finally {
            if(dos != null) {
              dos.close();
            }
            if(fos != null) {
              fos.close();
            }
          }
          logger.info("Setting " + MAPREDUCE_JOB_CREDENTIALS_BINARY + " to " + temp.getAbsolutePath());
          System.setProperty(MAPREDUCE_JOB_CREDENTIALS_BINARY, temp.getAbsolutePath());
        } else {
          logger.info("Not pre-fetching token");
        }
      }
    });

  }
}

