#!/usr/bin/python
"""
This is a script to submit rabit job using hadoop streaming
submit the rabit process as mappers of MapReduce
"""
import argparse
import sys
import os
import time
import subprocess
import rabit_tracker as tracker

#!!! Set path to hadoop and hadoop streaming jar here
hadoop_binary = None
hadoop_streaming_jar = None

# code 
hadoop_home = os.getenv('HADOOP_HOME')
if hadoop_home != None:
  if hadoop_binary == None:
    hadoop_binary = hadoop_home + '/bin/hadoop'
    assert os.path.exists(hadoop_binary), "HADDOP_HOME does not contain the hadoop binary"
  if hadoop_streaming_jar == None:
    hadoop_streaming_jar = hadoop_home + '/lib/hadoop-streaming.har'
    assert os.path.exists(hadoop_streaming_jar), "HADDOP_HOME does not contain the haddop streaming jar"

if hadoop_binary == None or hadoop_streaming_jar == None:
  print 'Warning: Cannot auto-detect path to hadoop and streaming jar, need to set them via arguments -hs and -hb'
  print '\tTo enable auto-detection, you can set enviroment variable HADOOP_HOME or modify rabit_hadoop.py line 14'

parser = argparse.ArgumentParser(description='Rabit script to submit rabit jobs using Hadoop Streaming')
parser.add_argument('-n', '--nslaves', required=True, type=int,
                    help = 'number of slaves proccess to be launched')
parser.add_argument('-v', '--verbose', default=0, choices=[0, 1], type=int,
                    help = 'print more messages into the console')
parser.add_argument('-i', '--input', required=True,
                    help = 'input path in HDFS')
parser.add_argument('-o', '--output', required=True,
                    help = 'output path in HDFS')
parser.add_argument('-f', '--files', nargs = '*',
                    help = 'the cached file list in mapreduce')
if hadoop_binary == None:
  parser.add_argument('-hb', '--hadoop_binary', required = True,
                      help="path-to-hadoop binary folder")  
else:
  parser.add_argument('-hb', '--hadoop_binary', default = hadoop_binary, 
                      help="path-to-hadoop binary folder")  

if hadoop_streaming_jar == None:
  parser.add_argument('-jar', '--hadoop_streaming_jar', required = True,
                      help='path-to hadoop streamimg jar file')
else:
  parser.add_argument('-jar', '--hadoop_streaming_jar', default = hadoop_streaming_jar,
                      help='path-to hadoop streamimg jar file')
parser.add_argument('command', nargs='+',
                    help = 'command for rabit program')
args = parser.parse_args()

def hadoop_streaming(nslaves, slave_args):
  cmd = '%s jar %s -D mapred.map.tasks=%d' % (args.hadoop_binary, args.hadoop_streaming_jar, nslaves)
  cmd += ' -input %s -output %s' % (args.input, args.output)
  cmd += ' -mapper \"%s\" -reducer \"/bin/cat\" ' % (' '.join(args.command + slave_args))
  fset = set()
  if os.path.exists(args.command[0]):
    fset.add(args.command[0])
  for flst in args.files:
    for f in flst.split('#'):
      fset.add(f)
  for f in fset:
    cmd += ' -file %s' % f
  print cmd
  subprocess.check_call(cmd, shell = True)

tracker.submit(args.nslaves, [], fun_submit = hadoop_streaming, verbose = args.verbose)