/**
    *
    * 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.mapreduce;
  
  import java.io.IOException;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  import java.util.UUID;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellUtil;
  import org.apache.hadoop.hbase.HBaseConfiguration;
  import org.apache.hadoop.hbase.KeyValue;
  import org.apache.hadoop.hbase.KeyValueUtil;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.ZooKeeperConnectionException;
  import org.apache.hadoop.hbase.client.Connection;
  import org.apache.hadoop.hbase.client.ConnectionFactory;
  import org.apache.hadoop.hbase.client.Delete;
  import org.apache.hadoop.hbase.client.Durability;
  import org.apache.hadoop.hbase.client.HBaseAdmin;
  import org.apache.hadoop.hbase.client.Mutation;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.client.RegionLocator;
  import org.apache.hadoop.hbase.client.Result;
  import org.apache.hadoop.hbase.client.Table;
  import org.apache.hadoop.hbase.filter.Filter;
  import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.zookeeper.ZKClusterId;
  import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
  import org.apache.hadoop.mapreduce.Job;
  import org.apache.hadoop.mapreduce.TaskCounter;
  import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
  import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat;
  import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
  import org.apache.hadoop.util.GenericOptionsParser;
  import org.apache.zookeeper.KeeperException;
  
  
  /**
   * Import data written by {@link Export}.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  public class Import {
    private static final Log LOG = LogFactory.getLog(Import.class);
    final static String NAME = "import";
    public final static String CF_RENAME_PROP = "HBASE_IMPORTER_RENAME_CFS";
    public final static String BULK_OUTPUT_CONF_KEY = "import.bulk.output";
    public final static String FILTER_CLASS_CONF_KEY = "import.filter.class";
    public final static String FILTER_ARGS_CONF_KEY = "import.filter.args";
    public final static String TABLE_NAME = "import.table.name";
    public final static String WAL_DURABILITY = "import.wal.durability";
  
    /**
     * A mapper that just writes out KeyValues.
     */
    @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="EQ_COMPARETO_USE_OBJECT_EQUALS",
        justification="Writables are going away and this has been this way forever")
    public static class KeyValueImporter extends TableMapper<ImmutableBytesWritable, KeyValue> {
      private Map<byte[], byte[]> cfRenameMap;
      private Filter filter;
      private static final Log LOG = LogFactory.getLog(KeyValueImporter.class);
  
      /**
       * @param row  The current table row key.
       * @param value  The columns.
       * @param context  The current context.
       * @throws IOException When something is broken with the data.
       */
      @Override
     public void map(ImmutableBytesWritable row, Result value,
       Context context)
     throws IOException {
       try {
         if (LOG.isTraceEnabled()) {
           LOG.trace("Considering the row."
               + Bytes.toString(row.get(), row.getOffset(), row.getLength()));
         }
         if (filter == null || !filter.filterRowKey(row.get(), row.getOffset(), row.getLength())) {
           for (Cell kv : value.rawCells()) {
             kv = filterKv(filter, kv);
             // skip if we filtered it out
             if (kv == null) continue;
             // TODO get rid of ensureKeyValue
             context.write(row, KeyValueUtil.ensureKeyValueTypeForMR(convertKv(kv, cfRenameMap)));
           }
         }
       } catch (InterruptedException e) {
         e.printStackTrace();
       }
     }
 
     @Override
     public void setup(Context context) {
       cfRenameMap = createCfRenameMap(context.getConfiguration());
       filter = instantiateFilter(context.getConfiguration());
     }
   }
 
   /**
    * Write table content out to files in hdfs.
    */
   public static class Importer extends TableMapper<ImmutableBytesWritable, Mutation> {
     private Map<byte[], byte[]> cfRenameMap;
     private List<UUID> clusterIds;
     private Filter filter;
     private Durability durability;
 
     /**
      * @param row  The current table row key.
      * @param value  The columns.
      * @param context  The current context.
      * @throws IOException When something is broken with the data.
      */
     @Override
     public void map(ImmutableBytesWritable row, Result value,
       Context context)
     throws IOException {
       try {
         writeResult(row, value, context);
       } catch (InterruptedException e) {
         e.printStackTrace();
       }
     }
 
     private void writeResult(ImmutableBytesWritable key, Result result, Context context)
     throws IOException, InterruptedException {
       Put put = null;
       Delete delete = null;
       if (LOG.isTraceEnabled()) {
         LOG.trace("Considering the row."
             + Bytes.toString(key.get(), key.getOffset(), key.getLength()));
       }
       if (filter == null || !filter.filterRowKey(key.get(), key.getOffset(), key.getLength())) {
         processKV(key, result, context, put, delete);
       }
     }
 
     protected void processKV(ImmutableBytesWritable key, Result result, Context context, Put put,
         Delete delete) throws IOException, InterruptedException {
       for (Cell kv : result.rawCells()) {
         kv = filterKv(filter, kv);
         // skip if we filter it out
         if (kv == null) continue;
 
         kv = convertKv(kv, cfRenameMap);
         // Deletes and Puts are gathered and written when finished
         /*
          * If there are sequence of mutations and tombstones in an Export, and after Import the same
          * sequence should be restored as it is. If we combine all Delete tombstones into single
          * request then there is chance of ignoring few DeleteFamily tombstones, because if we
          * submit multiple DeleteFamily tombstones in single Delete request then we are maintaining
          * only newest in hbase table and ignoring other. Check - HBASE-12065
          */
         if (CellUtil.isDeleteFamily(kv)) {
           Delete deleteFamily = new Delete(key.get());
           deleteFamily.addDeleteMarker(kv);
           if (durability != null) {
             deleteFamily.setDurability(durability);
           }
           deleteFamily.setClusterIds(clusterIds);
           context.write(key, deleteFamily);
         } else if (CellUtil.isDelete(kv)) {
           if (delete == null) {
             delete = new Delete(key.get());
           }
           delete.addDeleteMarker(kv);
         } else {
           if (put == null) {
             put = new Put(key.get());
           }
           addPutToKv(put, kv);
         }
       }
       if (put != null) {
         if (durability != null) {
           put.setDurability(durability);
         }
         put.setClusterIds(clusterIds);
         context.write(key, put);
       }
       if (delete != null) {
         if (durability != null) {
           delete.setDurability(durability);
         }
         delete.setClusterIds(clusterIds);
         context.write(key, delete);
       }
     }
 
     protected void addPutToKv(Put put, Cell kv) throws IOException {
       put.add(kv);
     }
 
     @Override
     public void setup(Context context) {
       Configuration conf = context.getConfiguration();
       cfRenameMap = createCfRenameMap(conf);
       filter = instantiateFilter(conf);
       String durabilityStr = conf.get(WAL_DURABILITY);
       if(durabilityStr != null){
         durability = Durability.valueOf(durabilityStr.toUpperCase());
       }
       // TODO: This is kind of ugly doing setup of ZKW just to read the clusterid.
       ZooKeeperWatcher zkw = null;
       Exception ex = null;
       try {
         zkw = new ZooKeeperWatcher(conf, context.getTaskAttemptID().toString(), null);
         clusterIds = Collections.singletonList(ZKClusterId.getUUIDForCluster(zkw));
       } catch (ZooKeeperConnectionException e) {
         ex = e;
         LOG.error("Problem connecting to ZooKeper during task setup", e);
       } catch (KeeperException e) {
         ex = e;
         LOG.error("Problem reading ZooKeeper data during task setup", e);
       } catch (IOException e) {
         ex = e;
         LOG.error("Problem setting up task", e);
       } finally {
         if (zkw != null) zkw.close();
       }
       if (clusterIds == null) {
         // exit early if setup fails
         throw new RuntimeException(ex);
       }
     }
   }
 
   /**
    * Create a {@link Filter} to apply to all incoming keys ({@link KeyValue KeyValues}) to
    * optionally not include in the job output
    * @param conf {@link Configuration} from which to load the filter
    * @return the filter to use for the task, or <tt>null</tt> if no filter to should be used
    * @throws IllegalArgumentException if the filter is misconfigured
    */
   public static Filter instantiateFilter(Configuration conf) {
     // get the filter, if it was configured    
     Class<? extends Filter> filterClass = conf.getClass(FILTER_CLASS_CONF_KEY, null, Filter.class);
     if (filterClass == null) {
       LOG.debug("No configured filter class, accepting all keyvalues.");
       return null;
     }
     LOG.debug("Attempting to create filter:" + filterClass);
     String[] filterArgs = conf.getStrings(FILTER_ARGS_CONF_KEY);
     ArrayList<byte[]> quotedArgs = toQuotedByteArrays(filterArgs);
     try {
       Method m = filterClass.getMethod("createFilterFromArguments", ArrayList.class);
       return (Filter) m.invoke(null, quotedArgs);
     } catch (IllegalAccessException e) {
       LOG.error("Couldn't instantiate filter!", e);
       throw new RuntimeException(e);
     } catch (SecurityException e) {
       LOG.error("Couldn't instantiate filter!", e);
       throw new RuntimeException(e);
     } catch (NoSuchMethodException e) {
       LOG.error("Couldn't instantiate filter!", e);
       throw new RuntimeException(e);
     } catch (IllegalArgumentException e) {
       LOG.error("Couldn't instantiate filter!", e);
       throw new RuntimeException(e);
     } catch (InvocationTargetException e) {
       LOG.error("Couldn't instantiate filter!", e);
       throw new RuntimeException(e);
     }
   }
 
   private static ArrayList<byte[]> toQuotedByteArrays(String... stringArgs) {
     ArrayList<byte[]> quotedArgs = new ArrayList<byte[]>();
     for (String stringArg : stringArgs) {
       // all the filters' instantiation methods expected quoted args since they are coming from
       // the shell, so add them here, though it shouldn't really be needed :-/
       quotedArgs.add(Bytes.toBytes("'" + stringArg + "'"));
     }
     return quotedArgs;
   }
 
   /**
    * Attempt to filter out the keyvalue
    * @param kv {@link KeyValue} on which to apply the filter
    * @return <tt>null</tt> if the key should not be written, otherwise returns the original
    *         {@link KeyValue}
    */
   public static Cell filterKv(Filter filter, Cell kv) throws IOException {
     // apply the filter and skip this kv if the filter doesn't apply
     if (filter != null) {
       Filter.ReturnCode code = filter.filterKeyValue(kv);
       if (LOG.isTraceEnabled()) {
         LOG.trace("Filter returned:" + code + " for the key value:" + kv);
       }
       // if its not an accept type, then skip this kv
       if (!(code.equals(Filter.ReturnCode.INCLUDE) || code
           .equals(Filter.ReturnCode.INCLUDE_AND_NEXT_COL))) {
         return null;
       }
     }
     return kv;
   }
 
   // helper: create a new KeyValue based on CF rename map
   private static Cell convertKv(Cell kv, Map<byte[], byte[]> cfRenameMap) {
     if(cfRenameMap != null) {
       // If there's a rename mapping for this CF, create a new KeyValue
       byte[] newCfName = cfRenameMap.get(CellUtil.cloneFamily(kv));
       if(newCfName != null) {
           kv = new KeyValue(kv.getRowArray(), // row buffer 
                   kv.getRowOffset(),        // row offset
                   kv.getRowLength(),        // row length
                   newCfName,                // CF buffer
                   0,                        // CF offset 
                   newCfName.length,         // CF length 
                   kv.getQualifierArray(),   // qualifier buffer
                   kv.getQualifierOffset(),  // qualifier offset
                   kv.getQualifierLength(),  // qualifier length
                   kv.getTimestamp(),        // timestamp
                   KeyValue.Type.codeToType(kv.getTypeByte()), // KV Type
                   kv.getValueArray(),       // value buffer 
                   kv.getValueOffset(),      // value offset
                   kv.getValueLength());     // value length
       }
     }
     return kv;
   }
 
   // helper: make a map from sourceCfName to destCfName by parsing a config key
   private static Map<byte[], byte[]> createCfRenameMap(Configuration conf) {
     Map<byte[], byte[]> cfRenameMap = null;
     String allMappingsPropVal = conf.get(CF_RENAME_PROP);
     if(allMappingsPropVal != null) {
       // The conf value format should be sourceCf1:destCf1,sourceCf2:destCf2,...
       String[] allMappings = allMappingsPropVal.split(",");
       for (String mapping: allMappings) {
         if(cfRenameMap == null) {
             cfRenameMap = new TreeMap<byte[],byte[]>(Bytes.BYTES_COMPARATOR);
         }
         String [] srcAndDest = mapping.split(":");
         if(srcAndDest.length != 2) {
             continue;
         }
         cfRenameMap.put(srcAndDest[0].getBytes(), srcAndDest[1].getBytes());
       }
     }
     return cfRenameMap;
   }
 
   /**
    * <p>Sets a configuration property with key {@link #CF_RENAME_PROP} in conf that tells
    * the mapper how to rename column families.
    * 
    * <p>Alternately, instead of calling this function, you could set the configuration key 
    * {@link #CF_RENAME_PROP} yourself. The value should look like 
    * <pre>srcCf1:destCf1,srcCf2:destCf2,....</pre>. This would have the same effect on
    * the mapper behavior.
    * 
    * @param conf the Configuration in which the {@link #CF_RENAME_PROP} key will be
    *  set
    * @param renameMap a mapping from source CF names to destination CF names
    */
   static public void configureCfRenaming(Configuration conf, 
           Map<String, String> renameMap) {
     StringBuilder sb = new StringBuilder();
     for(Map.Entry<String,String> entry: renameMap.entrySet()) {
       String sourceCf = entry.getKey();
       String destCf = entry.getValue();
 
       if(sourceCf.contains(":") || sourceCf.contains(",") || 
               destCf.contains(":") || destCf.contains(",")) {
         throw new IllegalArgumentException("Illegal character in CF names: " 
               + sourceCf + ", " + destCf);
       }
 
       if(sb.length() != 0) {
         sb.append(",");
       }
       sb.append(sourceCf + ":" + destCf);
     }
     conf.set(CF_RENAME_PROP, sb.toString());
   }
 
   /**
    * Add a Filter to be instantiated on import
    * @param conf Configuration to update (will be passed to the job)
    * @param clazz {@link Filter} subclass to instantiate on the server.
    * @param filterArgs List of arguments to pass to the filter on instantiation
    */
   public static void addFilterAndArguments(Configuration conf, Class<? extends Filter> clazz,
       List<String> filterArgs) throws IOException {
     conf.set(Import.FILTER_CLASS_CONF_KEY, clazz.getName());
     conf.setStrings(Import.FILTER_ARGS_CONF_KEY, filterArgs.toArray(new String[filterArgs.size()]));
   }
 
   /**
    * Sets up the actual job.
    * @param conf The current configuration.
    * @param args The command line parameters.
    * @return The newly created job.
    * @throws IOException When setting up the job fails.
    */
   public static Job createSubmittableJob(Configuration conf, String[] args)
   throws IOException {
     TableName tableName = TableName.valueOf(args[0]);
     conf.set(TABLE_NAME, tableName.getNameAsString());
     Path inputDir = new Path(args[1]);
     Job job = new Job(conf, NAME + "_" + tableName);
     job.setJarByClass(Importer.class);
     FileInputFormat.setInputPaths(job, inputDir);
     job.setInputFormatClass(SequenceFileInputFormat.class);
     String hfileOutPath = conf.get(BULK_OUTPUT_CONF_KEY);
 
     // make sure we get the filter in the jars
     try {
       Class<? extends Filter> filter = conf.getClass(FILTER_CLASS_CONF_KEY, null, Filter.class);
       if (filter != null) {
         TableMapReduceUtil.addDependencyJars(conf, filter);
       }
     } catch (Exception e) {
       throw new IOException(e);
     }
 
     if (hfileOutPath != null) {
       job.setMapperClass(KeyValueImporter.class);
       try (Connection conn = ConnectionFactory.createConnection(conf); 
           Table table = conn.getTable(tableName);
           RegionLocator regionLocator = conn.getRegionLocator(tableName)){
         job.setReducerClass(KeyValueSortReducer.class);
         Path outputDir = new Path(hfileOutPath);
         FileOutputFormat.setOutputPath(job, outputDir);
         job.setMapOutputKeyClass(ImmutableBytesWritable.class);
         job.setMapOutputValueClass(KeyValue.class);
         HFileOutputFormat2.configureIncrementalLoad(job, table.getTableDescriptor(), regionLocator);
         TableMapReduceUtil.addDependencyJars(job.getConfiguration(),
             com.google.common.base.Preconditions.class);
       }
     } else {
       // No reducers.  Just write straight to table.  Call initTableReducerJob
       // because it sets up the TableOutputFormat.
       job.setMapperClass(Importer.class);
       TableMapReduceUtil.initTableReducerJob(tableName.getNameAsString(), null, job);
       job.setNumReduceTasks(0);
     }
     return job;
   }
 
   /*
    * @param errorMsg Error message.  Can be null.
    */
   private static void usage(final String errorMsg) {
     if (errorMsg != null && errorMsg.length() > 0) {
       System.err.println("ERROR: " + errorMsg);
     }
     System.err.println("Usage: Import [options] <tablename> <inputdir>");
     System.err.println("By default Import will load data directly into HBase. To instead generate");
     System.err.println("HFiles of data to prepare for a bulk data load, pass the option:");
     System.err.println("  -D" + BULK_OUTPUT_CONF_KEY + "=/path/for/output");
     System.err
         .println(" To apply a generic org.apache.hadoop.hbase.filter.Filter to the input, use");
     System.err.println("  -D" + FILTER_CLASS_CONF_KEY + "=<name of filter class>");
     System.err.println("  -D" + FILTER_ARGS_CONF_KEY + "=<comma separated list of args for filter");
     System.err.println(" NOTE: The filter will be applied BEFORE doing key renames via the "
         + CF_RENAME_PROP + " property. Futher, filters will only use the"
         + " Filter#filterRowKey(byte[] buffer, int offset, int length) method to identify "
         + " whether the current row needs to be ignored completely for processing and "
         + " Filter#filterKeyValue(KeyValue) method to determine if the KeyValue should be added;"
         + " Filter.ReturnCode#INCLUDE and #INCLUDE_AND_NEXT_COL will be considered as including"
         + " the KeyValue.");
     System.err.println("To import data exported from HBase 0.94, use");
     System.err.println("  -Dhbase.import.version=0.94");
     System.err.println("For performance consider the following options:\n"
         + "  -Dmapreduce.map.speculative=false\n"
         + "  -Dmapreduce.reduce.speculative=false\n"
         + "  -D" + WAL_DURABILITY + "=<Used while writing data to hbase."
             +" Allowed values are the supported durability values"
             +" like SKIP_WAL/ASYNC_WAL/SYNC_WAL/...>");
   }
 
   /**
    * If the durability is set to {@link Durability#SKIP_WAL} and the data is imported to hbase, we
    * need to flush all the regions of the table as the data is held in memory and is also not
    * present in the Write Ahead Log to replay in scenarios of a crash. This method flushes all the
    * regions of the table in the scenarios of import data to hbase with {@link Durability#SKIP_WAL}
    */
   public static void flushRegionsIfNecessary(Configuration conf) throws IOException,
       InterruptedException {
     String tableName = conf.get(TABLE_NAME);
     HBaseAdmin hAdmin = null;
     String durability = conf.get(WAL_DURABILITY);
     // Need to flush if the data is written to hbase and skip wal is enabled.
     if (conf.get(BULK_OUTPUT_CONF_KEY) == null && durability != null
         && Durability.SKIP_WAL.name().equalsIgnoreCase(durability)) {
       try {
         hAdmin = new HBaseAdmin(conf);
         hAdmin.flush(tableName);
       } finally {
         if (hAdmin != null) {
           hAdmin.close();
         }
       }
     }
   }
 
   /**
    * Main entry point.
    *
    * @param args  The command line parameters.
    * @throws Exception When running the job fails.
    */
   public static void main(String[] args) throws Exception {
     Configuration conf = HBaseConfiguration.create();
     String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
     if (otherArgs.length < 2) {
       usage("Wrong number of arguments: " + otherArgs.length);
       System.exit(-1);
     }
     String inputVersionString = System.getProperty(ResultSerialization.IMPORT_FORMAT_VER);
     if (inputVersionString != null) {
       conf.set(ResultSerialization.IMPORT_FORMAT_VER, inputVersionString);
     }
     Job job = createSubmittableJob(conf, otherArgs);
     boolean isJobSuccessful = job.waitForCompletion(true);
     if(isJobSuccessful){
       // Flush all the regions of the table
       flushRegionsIfNecessary(conf);
     }
     long inputRecords = job.getCounters().findCounter(TaskCounter.MAP_INPUT_RECORDS).getValue();
     long outputRecords = job.getCounters().findCounter(TaskCounter.MAP_OUTPUT_RECORDS).getValue();
     if (outputRecords < inputRecords) {
       System.err.println("Warning, not all records were imported (maybe filtered out).");
       if (outputRecords == 0) {
         System.err.println("If the data was exported from HBase 0.94 "+
             "consider using -Dhbase.import.version=0.94.");
       }
     }
 
     System.exit(isJobSuccessful ? 0 : 1);
   }
 }