#!/usr/bin/python
# Copyright (c) 2010 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.

"""Runs tests on VMs in parallel."""

import optparse
import os
import subprocess
import sys
import tempfile

sys.path.append(os.path.join(os.path.dirname(__file__), '../lib'))
from cros_build_lib import Die
from cros_build_lib import Info


_DEFAULT_BASE_SSH_PORT = 9222

class ParallelTestRunner(object):
  """Runs tests on VMs in parallel.

  This class is a simple wrapper around cros_run_vm_test that provides an easy
  way to spawn several test instances in parallel and aggregate the results when
  the tests complete.
  """

  def __init__(self, tests, base_ssh_port=_DEFAULT_BASE_SSH_PORT, board=None,
               image_path=None, order_output=False, results_dir_root=None):
    """Constructs and initializes the test runner class.

    Args:
      tests: A list of test names (see run_remote_tests.sh).
      base_ssh_port: The base SSH port. Spawned VMs listen to localhost SSH
        ports incrementally allocated starting from the base one.
      board: The target board. If none, cros_run_vm_tests will use the default
        board.
      image_path: Full path to the VM image. If none, cros_run_vm_tests will use
        the latest image.
      order_output: If True, output of individual VMs will be piped to
        temporary files and emitted at the end.
      results_dir_root: The results directory root. If provided, the results
        directory root for each test will be created under it with the SSH port
        appended to the test name.
    """
    self._tests = tests
    self._base_ssh_port = base_ssh_port
    self._board = board
    self._image_path = image_path
    self._order_output = order_output
    self._results_dir_root = results_dir_root

  def _SpawnTests(self):
    """Spawns VMs and starts the test runs on them.

    Runs all tests in |self._tests|. Each test is executed on a separate VM.

    Returns:
      A list of test process info objects containing the following dictionary
      entries:
        'test': the test name;
        'proc': the Popen process instance for this test run.
    """
    ssh_port = self._base_ssh_port
    spawned_tests = []
    # Test runs shouldn't need anything from stdin. However, it seems that
    # running with stdin leaves the terminal in a bad state so redirect from
    # /dev/null.
    dev_null = open('/dev/null')
    for test in self._tests:
      args = [ os.path.join(os.path.dirname(__file__), 'cros_run_vm_test'),
               '--snapshot',  # The image is shared so don't modify it.
               '--no_graphics',
               '--ssh_port=%d' % ssh_port,
               '--test_case=%s' % test ]
      if self._board: args.append('--board=%s' % self._board)
      if self._image_path: args.append('--image_path=%s' % self._image_path)
      if self._results_dir_root:
        args.append('--results_dir_root=%s/%s.%d' %
                    (self._results_dir_root, test, ssh_port))
      Info('Running %r...' % args)
      output = None
      if self._order_output:
        output = tempfile.NamedTemporaryFile(prefix='parallel_vm_test_')
        Info('Piping output to %s.' % output.name)
      proc = subprocess.Popen(args, stdin=dev_null, stdout=output,
                              stderr=output)
      test_info = { 'test': test,
                    'proc': proc,
                    'output': output }
      spawned_tests.append(test_info)
      ssh_port = ssh_port + 1
    return spawned_tests

  def _WaitForCompletion(self, spawned_tests):
    """Waits for tests to complete and returns a list of failed tests.

    If the test output was piped to a file, dumps the file contents to stdout.

    Args:
      spawned_tests: A list of test info objects (see _SpawnTests).

    Returns:
      A list of failed test names.
    """
    failed_tests = []
    for test_info in spawned_tests:
      proc = test_info['proc']
      proc.wait()
      if proc.returncode: failed_tests.append(test_info['test'])
      output = test_info['output']
      if output:
        test = test_info['test']
        Info('------ START %s:%s ------' % (test, output.name))
        output.seek(0)
        for line in output:
          print line,
        Info('------ END %s:%s ------' % (test, output.name))
    return failed_tests

  def Run(self):
    """Runs the tests in |self._tests| on separate VMs in parallel."""
    spawned_tests = self._SpawnTests()
    failed_tests = self._WaitForCompletion(spawned_tests)
    if failed_tests: Die('Tests failed: %r' % failed_tests)


def main():
  usage = 'Usage: %prog [options] tests...'
  parser = optparse.OptionParser(usage=usage)
  parser.add_option('--base_ssh_port', type='int',
                    default=_DEFAULT_BASE_SSH_PORT,
                    help='Base SSH port. Spawned VMs listen to localhost SSH '
                    'ports incrementally allocated starting from the base one. '
                    '[default: %default]')
  parser.add_option('--board',
                    help='The target board. If none specified, '
                    'cros_run_vm_test will use the default board.')
  parser.add_option('--image_path',
                    help='Full path to the VM image. If none specified, '
                    'cros_run_vm_test will use the latest image.')
  parser.add_option('--order_output', action='store_true', default=False,
                    help='Rather than emitting interleaved progress output '
                    'from the individual VMs, accumulate the outputs in '
                    'temporary files and dump them at the end.')
  parser.add_option('--results_dir_root',
                    help='Root results directory. If none specified, each test '
                    'will store its results in a separate /tmp directory.')
  (options, args) = parser.parse_args()

  if not args:
    parser.print_help()
    Die('no tests provided')

  runner = ParallelTestRunner(args, options.base_ssh_port, options.board,
                              options.image_path, options.order_output,
                              options.results_dir_root)
  runner.Run()


if __name__ == '__main__':
  main()