/**
    *
    * 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.hbase.mapred;
  
  import java.io.IOException;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.MetaTableAccessor;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.client.Connection;
  import org.apache.hadoop.hbase.client.ConnectionFactory;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
  import org.apache.hadoop.hbase.mapreduce.MutationSerialization;
  import org.apache.hadoop.hbase.mapreduce.ResultSerialization;
  import org.apache.hadoop.hbase.security.token.AuthenticationTokenIdentifier;
  import org.apache.hadoop.hbase.security.token.AuthenticationTokenSelector;
  import org.apache.hadoop.hbase.security.User;
  import org.apache.hadoop.hbase.security.UserProvider;
  import org.apache.hadoop.hbase.security.token.TokenUtil;
  import org.apache.hadoop.hbase.zookeeper.ZKClusterId;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
  import org.apache.hadoop.io.Text;
  import org.apache.hadoop.mapred.FileInputFormat;
  import org.apache.hadoop.mapred.InputFormat;
  import org.apache.hadoop.mapred.JobConf;
  import org.apache.hadoop.mapred.OutputFormat;
  import org.apache.hadoop.mapred.TextInputFormat;
  import org.apache.hadoop.mapred.TextOutputFormat;
  import org.apache.hadoop.security.token.Token;
  import org.apache.zookeeper.KeeperException;
  
  /**
   * Utility for {@link TableMap} and {@link TableReduce}
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  @SuppressWarnings({ "rawtypes", "unchecked" })
  public class TableMapReduceUtil {
  
    /**
     * Use this before submitting a TableMap job. It will
     * appropriately set up the JobConf.
     *
     * @param table  The table name to read from.
     * @param columns  The columns to scan.
     * @param mapper  The mapper class to use.
     * @param outputKeyClass  The class of the output key.
     * @param outputValueClass  The class of the output value.
     * @param job  The current job configuration to adjust.
     */
    public static void initTableMapJob(String table, String columns,
      Class<? extends TableMap> mapper,
      Class<?> outputKeyClass,
      Class<?> outputValueClass, JobConf job) {
      initTableMapJob(table, columns, mapper, outputKeyClass, outputValueClass, job,
        true, TableInputFormat.class);
    }
  
    public static void initTableMapJob(String table, String columns,
      Class<? extends TableMap> mapper,
      Class<?> outputKeyClass,
      Class<?> outputValueClass, JobConf job, boolean addDependencyJars) {
      initTableMapJob(table, columns, mapper, outputKeyClass, outputValueClass, job,
        addDependencyJars, TableInputFormat.class);
    }
  
    /**
     * Use this before submitting a TableMap job. It will
     * appropriately set up the JobConf.
     *
     * @param table  The table name to read from.
     * @param columns  The columns to scan.
     * @param mapper  The mapper class to use.
     * @param outputKeyClass  The class of the output key.
     * @param outputValueClass  The class of the output value.
     * @param job  The current job configuration to adjust.
     * @param addDependencyJars upload HBase jars and jars for any of the configured
     *           job classes via the distributed cache (tmpjars).
    */
   public static void initTableMapJob(String table, String columns,
     Class<? extends TableMap> mapper,
     Class<?> outputKeyClass,
     Class<?> outputValueClass, JobConf job, boolean addDependencyJars,
     Class<? extends InputFormat> inputFormat) {
 
     job.setInputFormat(inputFormat);
     job.setMapOutputValueClass(outputValueClass);
     job.setMapOutputKeyClass(outputKeyClass);
     job.setMapperClass(mapper);
     job.setStrings("io.serializations", job.get("io.serializations"),
         MutationSerialization.class.getName(), ResultSerialization.class.getName());
     FileInputFormat.addInputPaths(job, table);
     job.set(TableInputFormat.COLUMN_LIST, columns);
     if (addDependencyJars) {
       try {
         addDependencyJars(job);
       } catch (IOException e) {
         e.printStackTrace();
       }
     }
     try {
       initCredentials(job);
     } catch (IOException ioe) {
       // just spit out the stack trace?  really?
       ioe.printStackTrace();
     }
   }
 
   /**
    * Sets up the job for reading from a table snapshot. It bypasses hbase servers
    * and read directly from snapshot files.
    *
    * @param snapshotName The name of the snapshot (of a table) to read from.
    * @param columns  The columns to scan.
    * @param mapper  The mapper class to use.
    * @param outputKeyClass  The class of the output key.
    * @param outputValueClass  The class of the output value.
    * @param job  The current job to adjust.  Make sure the passed job is
    * carrying all necessary HBase configuration.
    * @param addDependencyJars upload HBase jars and jars for any of the configured
    *           job classes via the distributed cache (tmpjars).
    * @param tmpRestoreDir a temporary directory to copy the snapshot files into. Current user should
    * have write permissions to this directory, and this should not be a subdirectory of rootdir.
    * After the job is finished, restore directory can be deleted.
    * @throws IOException When setting up the details fails.
    * @see TableSnapshotInputFormat
    */
   public static void initTableSnapshotMapJob(String snapshotName, String columns,
       Class<? extends TableMap> mapper,
       Class<?> outputKeyClass,
       Class<?> outputValueClass, JobConf job,
       boolean addDependencyJars, Path tmpRestoreDir)
   throws IOException {
     TableSnapshotInputFormat.setInput(job, snapshotName, tmpRestoreDir);
     initTableMapJob(snapshotName, columns, mapper, outputKeyClass, outputValueClass, job,
       addDependencyJars, TableSnapshotInputFormat.class);
     org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil.resetCacheConfig(job);
   }
 
   /**
    * Use this before submitting a TableReduce job. It will
    * appropriately set up the JobConf.
    *
    * @param table  The output table.
    * @param reducer  The reducer class to use.
    * @param job  The current job configuration to adjust.
    * @throws IOException When determining the region count fails.
    */
   public static void initTableReduceJob(String table,
     Class<? extends TableReduce> reducer, JobConf job)
   throws IOException {
     initTableReduceJob(table, reducer, job, null);
   }
 
   /**
    * Use this before submitting a TableReduce job. It will
    * appropriately set up the JobConf.
    *
    * @param table  The output table.
    * @param reducer  The reducer class to use.
    * @param job  The current job configuration to adjust.
    * @param partitioner  Partitioner to use. Pass <code>null</code> to use
    * default partitioner.
    * @throws IOException When determining the region count fails.
    */
   public static void initTableReduceJob(String table,
     Class<? extends TableReduce> reducer, JobConf job, Class partitioner)
   throws IOException {
     initTableReduceJob(table, reducer, job, partitioner, true);
   }
 
   /**
    * Use this before submitting a TableReduce job. It will
    * appropriately set up the JobConf.
    *
    * @param table  The output table.
    * @param reducer  The reducer class to use.
    * @param job  The current job configuration to adjust.
    * @param partitioner  Partitioner to use. Pass <code>null</code> to use
    * default partitioner.
    * @param addDependencyJars upload HBase jars and jars for any of the configured
    *           job classes via the distributed cache (tmpjars).
    * @throws IOException When determining the region count fails.
    */
   public static void initTableReduceJob(String table,
     Class<? extends TableReduce> reducer, JobConf job, Class partitioner,
     boolean addDependencyJars) throws IOException {
     job.setOutputFormat(TableOutputFormat.class);
     job.setReducerClass(reducer);
     job.set(TableOutputFormat.OUTPUT_TABLE, table);
     job.setOutputKeyClass(ImmutableBytesWritable.class);
     job.setOutputValueClass(Put.class);
     job.setStrings("io.serializations", job.get("io.serializations"),
         MutationSerialization.class.getName(), ResultSerialization.class.getName());
     if (partitioner == HRegionPartitioner.class) {
       job.setPartitionerClass(HRegionPartitioner.class);
       int regions =
         MetaTableAccessor.getRegionCount(HBaseConfiguration.create(job), TableName.valueOf(table));
       if (job.getNumReduceTasks() > regions) {
         job.setNumReduceTasks(regions);
       }
     } else if (partitioner != null) {
       job.setPartitionerClass(partitioner);
     }
     if (addDependencyJars) {
       addDependencyJars(job);
     }
     initCredentials(job);
   }
 
   public static void initCredentials(JobConf job) throws IOException {
     UserProvider userProvider = UserProvider.instantiate(job);
     if (userProvider.isHadoopSecurityEnabled()) {
       // propagate delegation related props from launcher job to MR job
       if (System.getenv("HADOOP_TOKEN_FILE_LOCATION") != null) {
         job.set("mapreduce.job.credentials.binary", System.getenv("HADOOP_TOKEN_FILE_LOCATION"));
       }
     }
 
     if (userProvider.isHBaseSecurityEnabled()) {
       Connection conn = ConnectionFactory.createConnection(job);
       try {
         // login the server principal (if using secure Hadoop)
         User user = userProvider.getCurrent();
         TokenUtil.addTokenForJob(conn, job, user);
       } catch (InterruptedException ie) {
         ie.printStackTrace();
         Thread.currentThread().interrupt();
       } finally {
         conn.close();
       }
     }
   }
 
   /**
    * Ensures that the given number of reduce tasks for the given job
    * configuration does not exceed the number of regions for the given table.
    *
    * @param table  The table to get the region count for.
    * @param job  The current job configuration to adjust.
    * @throws IOException When retrieving the table details fails.
    */
   // Used by tests.
   public static void limitNumReduceTasks(String table, JobConf job)
   throws IOException {
     int regions =
       MetaTableAccessor.getRegionCount(HBaseConfiguration.create(job), TableName.valueOf(table));
     if (job.getNumReduceTasks() > regions)
       job.setNumReduceTasks(regions);
   }
 
   /**
    * Ensures that the given number of map tasks for the given job
    * configuration does not exceed the number of regions for the given table.
    *
    * @param table  The table to get the region count for.
    * @param job  The current job configuration to adjust.
    * @throws IOException When retrieving the table details fails.
    */
   // Used by tests.
   public static void limitNumMapTasks(String table, JobConf job)
   throws IOException {
     int regions =
       MetaTableAccessor.getRegionCount(HBaseConfiguration.create(job), TableName.valueOf(table));
     if (job.getNumMapTasks() > regions)
       job.setNumMapTasks(regions);
   }
 
   /**
    * Sets the number of reduce tasks for the given job configuration to the
    * number of regions the given table has.
    *
    * @param table  The table to get the region count for.
    * @param job  The current job configuration to adjust.
    * @throws IOException When retrieving the table details fails.
    */
   public static void setNumReduceTasks(String table, JobConf job)
   throws IOException {
     job.setNumReduceTasks(MetaTableAccessor.getRegionCount(HBaseConfiguration.create(job),
       TableName.valueOf(table)));
   }
 
   /**
    * Sets the number of map tasks for the given job configuration to the
    * number of regions the given table has.
    *
    * @param table  The table to get the region count for.
    * @param job  The current job configuration to adjust.
    * @throws IOException When retrieving the table details fails.
    */
   public static void setNumMapTasks(String table, JobConf job)
   throws IOException {
     job.setNumMapTasks(MetaTableAccessor.getRegionCount(HBaseConfiguration.create(job),
       TableName.valueOf(table)));
   }
 
   /**
    * Sets the number of rows to return and cache with each scanner iteration.
    * Higher caching values will enable faster mapreduce jobs at the expense of
    * requiring more heap to contain the cached rows.
    *
    * @param job The current job configuration to adjust.
    * @param batchSize The number of rows to return in batch with each scanner
    * iteration.
    */
   public static void setScannerCaching(JobConf job, int batchSize) {
     job.setInt("hbase.client.scanner.caching", batchSize);
   }
 
   /**
    * @see org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil#addDependencyJars(org.apache.hadoop.mapreduce.Job)
    */
   public static void addDependencyJars(JobConf job) throws IOException {
     org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil.addHBaseDependencyJars(job);
     org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil.addDependencyJars(
       job,
       // when making changes here, consider also mapreduce.TableMapReduceUtil
       // pull job classes
       job.getMapOutputKeyClass(),
       job.getMapOutputValueClass(),
       job.getOutputKeyClass(),
       job.getOutputValueClass(),
       job.getPartitionerClass(),
       job.getClass("mapred.input.format.class", TextInputFormat.class, InputFormat.class),
       job.getClass("mapred.output.format.class", TextOutputFormat.class, OutputFormat.class),
       job.getCombinerClass());
   }
 }