#!/usr/bin/python
#
# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

__help__ = """Script to archive old Autotest results to Google Storage.

Uses gsutil to archive files to the configured Google Storage bucket. Upon
successful copy, the local results directory is deleted.
"""

__author__ = 'dalecurtis@google.com (Dale Curtis)'

import logging
import os
import re
import shutil
import signal
import subprocess
import sys
import tempfile
import time

import is_job_complete

# Google Storage bucket URI to store results in.
GS_URI = 'gs://chromeos-autotest-results'

# Set this to True to enable rsync otherwise results are offloaded to GS.
USE_RSYNC = False
RSYNC_HOST_PATH = 'chromeos-sam1:/usr/local/autotest/results/'

# Nice setting for process, the higher the number the lower the priority.
NICENESS = 10

# Setting timeout to 3 hours.
TIMEOUT = 3 * 60 * 60

# Location of Autotest results on disk.
RESULTS_DIR = '/usr/local/autotest/results'

# Success constant to check if a job is completed.
JOB_COMPLETED = 0

LOG_FILENAME_FORMAT = ('/usr/local/autotest/logs/'
                       'gs_offloader_log_%Y%m%d_%H%M%S.txt')
LOGGING_FORMAT = '%(asctime)s - %(levelname)s - %(message)s'

CLEAN_CMD = 'find %s -iname chrome_20[0-9][0-9]\* -exec rm {} \;'


class TimeoutException(Exception):
  pass


def timeout_handler(_signum, _frame):
  """
  Called by the SIGALRM if the offloading process has timed out.

  @raise TimeoutException: Automatically raises so that the time out is caught
                           by the try/except surrounding the Popen call.
  """
  raise TimeoutException('Process Timed Out')


def get_cmd_list(dir_entry):
  """
  Generate the cmd_list for the specified directory entry.

  @param dir_entry: Directory entry/path that which we need a cmd_list to
                    offload.

  @return: A command list to be executed by Popen.
  """
  if USE_RSYNC:
    logging.debug('Using rsync for offloading %s to %s.', dir_entry,
                  RSYNC_HOST_PATH)
    return ['rsync', '-a', dir_entry, RSYNC_HOST_PATH]
  else:
    logging.debug('Using google storage for offloading %s to %s.',
                  dir_entry, GS_URI)
    return ['gsutil', '-m', 'cp', '-eR', '-a', 'project-private', dir_entry,
            GS_URI]


def offload_dir(dir_entry):
  """
  Offload the specified directory entry to the Google storage or the RSYNC host,
  but timeout if it takes too long.

  @param dir_entry: Directory entry to offload.
  """
  try:
    error = False
    signal.alarm(TIMEOUT)
    stdout_file = tempfile.TemporaryFile('w+')
    stderr_file = tempfile.TemporaryFile('w+')
    process = subprocess.Popen(get_cmd_list(dir_entry), stdout=stdout_file,
                               stderr=stderr_file)
    process.wait()
    signal.alarm(0)
    if process.returncode == 0:
      shutil.rmtree(dir_entry)
    else:
      error = True
  except TimeoutException:
    process.terminate()
    logging.error('Offloading %s timed out after waiting %d seconds.',
                  dir_entry, TIMEOUT)
    error = True
  finally:
    signal.alarm(0)
    if error:
      # Rewind the log files for stdout and stderr and log their contents.
      stdout_file.seek(0)
      stderr_file.seek(0)
      logging.error('Stdout:\n%s \nStderr:\n%s', stdout_file.read(),
                    stderr_file.read())
    stdout_file.close()
    stderr_file.close()


def offload_files(results_dir):
  """
  Offload files to Google Storage or the RSYNC_HOST_PATH host if USE_RSYNC is
  True.

  To ensure that the offloading times out properly we utilize a SIGALRM by
  assigning a simple function, timeout_handler, to be called if the SIGALRM is
  raised. timeout_handler will raise an exception that we can catch so that we
  know the timeout has occured and can react accordingly.

  @param results_dir: The Autotest results dir to look for dirs to offload.
  """
  # Nice our process (carried to subprocesses) so we don't kill the system.
  os.nice(NICENESS)
  logging.debug('Set process to nice value: %d', NICENESS)
  # os.listdir returns relative paths, so change to where we need to be to avoid
  # an os.path.join on each loop.
  os.chdir(results_dir)
  logging.debug('Looking for Autotest results in %s', results_dir)
  # Only pick up directories of the form <job #>-<job user>.
  job_matcher = re.compile('^\d+-\w+')
  signal.signal(signal.SIGALRM, timeout_handler)
  while True:
    # Iterate over all directories in results_dir.
    for dir_entry in os.listdir('.'):
      logging.debug('Processing %s', dir_entry)
      if not job_matcher.match(dir_entry):
        logging.debug('Skipping dir %s', dir_entry)
        continue
      # Directory names are in the format of <job #>-<job user>. We want just
      # the job # to see if it has completed.
      job_id = os.path.basename(dir_entry).split('-')[0]
      if is_job_complete.is_job_complete(job_id) is not JOB_COMPLETED:
        logging.debug('Job %s is not yet complete; skipping.', dir_entry)
        continue
      if (job_matcher.match(dir_entry) and os.path.isdir(dir_entry)):
        # The way we collect results currently is naive and results in a lot
        # of extra data collection. Clear these for now until we can be more
        # exact about what logs we care about. crosbug.com/26784.
        logging.debug('Cleaning %s of extra data.', dir_entry)
        os.system(CLEAN_CMD % dir_entry)
        offload_dir(dir_entry)


def _check_args_and_print_usage(args):
  """
  Check that no args have been passed to gs_offloader, and if so print out the
  proper usage.

  @param args: Command line args passed into gs_offloader.
  """
  if len(args) > 1:
    print __help__
    print 'Defaults:'
    print '  Destination: ' + GS_URI
    print '  Results path: ' + RESULTS_DIR
    print '\nUsage:'
    print '  ./gs_offloader.py\n'
    sys.exit(0)


def main():
  _check_args_and_print_usage(sys.argv)
  log_filename = time.strftime(LOG_FILENAME_FORMAT)
  logging.basicConfig(filename=log_filename, level=logging.DEBUG,
                      format=LOGGING_FORMAT)
  offload_files(RESULTS_DIR)


if __name__ == '__main__':
  main()