scripts/cbuildbot.py

#!/usr/bin/python

# Copyright (c) 2011-2012 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.

"""Main builder code for Chromium OS.

Used by Chromium OS buildbot configuration for all Chromium OS builds including
full and pre-flight-queue builds.
"""

import distutils.version
import glob
import multiprocessing
import optparse
import os
import pprint
import sys

from chromite.buildbot import builderstage as bs
from chromite.buildbot import cbuildbot_background as background
from chromite.buildbot import cbuildbot_config
from chromite.buildbot import cbuildbot_stages as stages
from chromite.buildbot import cbuildbot_results as results_lib
from chromite.buildbot import constants
from chromite.buildbot import gerrit_helper
from chromite.buildbot import patch as cros_patch
from chromite.buildbot import remote_try
from chromite.buildbot import repository
from chromite.buildbot import tee

from chromite.lib import cgroups
from chromite.lib import cleanup
from chromite.lib import cros_build_lib as cros_lib
from chromite.lib import sudo


cros_lib.STRICT_SUDO = True

_DEFAULT_LOG_DIR = 'cbuildbot_logs'
_BUILDBOT_LOG_FILE = 'cbuildbot.log'
_DEFAULT_EXT_BUILDROOT = 'trybot'
_DEFAULT_INT_BUILDROOT = 'trybot-internal'
_PATH_TO_CBUILDBOT = 'chromite/bin/cbuildbot'
_DISTRIBUTED_TYPES = [constants.COMMIT_QUEUE_TYPE, constants.PFQ_TYPE,
                      constants.CANARY_TYPE, constants.CHROME_PFQ_TYPE,
                      constants.PALADIN_TYPE]
_BUILDBOT_REQUIRED_BINARIES = ('pbzip2',)


def _PrintValidConfigs(trybot_only=True):
  """Print a list of valid buildbot configs.

  Arguments:
    trybot_only: Only print selected trybot configs, as specified by the
                 'trybot_list' config setting.
  """
  COLUMN_WIDTH = 45
  print 'config'.ljust(COLUMN_WIDTH), 'description'
  print '------'.ljust(COLUMN_WIDTH), '-----------'
  config_names = cbuildbot_config.config.keys()
  config_names.sort()
  for name in config_names:
    if not trybot_only or cbuildbot_config.config[name]['trybot_list']:
      desc = ''
      if cbuildbot_config.config[name]['description']:
        desc = cbuildbot_config.config[name]['description']

      print name.ljust(COLUMN_WIDTH), desc


def _GetConfig(config_name):
  """Gets the configuration for the build"""
  if not cbuildbot_config.config.has_key(config_name):
    print 'Non-existent configuration %s specified.' % config_name
    print 'Please specify one of:'
    _PrintValidConfigs()
    sys.exit(1)

  result = cbuildbot_config.config[config_name]

  return result


def _GetChromiteTrackingBranch():
  """Returns the remote branch associated with chromite."""
  cwd = os.path.dirname(os.path.realpath(__file__))
  branch = cros_lib.GetCurrentBranch(cwd)
  if branch:
    tracking_branch = cros_lib.GetTrackingBranch(branch, cwd)[1]
    if tracking_branch.startswith('refs/heads/'):
      return tracking_branch.replace('refs/heads/', '')
  # If we are not on a branch, or if the tracking branch is a revision,
  # use the default manifest branch. This only works if we are in a
  # repo repository. TODO(davidjames): Fix this to work if we're not in a repo
  # repository.
  return cros_lib.GetManifestDefaultBranch(cwd)


def _CheckBuildRootBranch(buildroot, tracking_branch):
  """Make sure buildroot branch is the same as Chromite branch."""
  manifest_branch = cros_lib.GetManifestDefaultBranch(buildroot)
  if manifest_branch != tracking_branch:
    cros_lib.Die('Chromite is not on same branch as buildroot checkout\n' +
                 'Chromite is on branch %s.\n' % tracking_branch +
                 'Buildroot checked out to %s\n' % manifest_branch)


def _PreProcessPatches(gerrit_patches, local_patches):
  """Validate patches ASAP to catch user errors.  Also generate patch info.

  Args:
    gerrit_patches: List of gerrit CL ID's passed in by user.
    local_patches: List of local project branches to generate patches from.

  Returns:
    A tuple containing a list of cros_patch.GerritPatch and a list of
    cros_patch.LocalPatch objects.
  """
  gerrit_patch_info = []
  local_patch_info = []

  try:
    if gerrit_patches:
      gerrit_patch_info = gerrit_helper.GetGerritPatchInfo(gerrit_patches)
      for patch in gerrit_patch_info:
        if patch.IsAlreadyMerged():
          cros_lib.Warning('Patch %s has already been merged.' % str(patch))
  except gerrit_helper.GerritException as e:
    cros_lib.Die(str(e))

  try:
    if local_patches:
      local_patch_info = cros_patch.PrepareLocalPatches(
          local_patches,
          _GetChromiteTrackingBranch())

  except cros_patch.PatchException as e:
    cros_lib.Die(str(e))

  return gerrit_patch_info, local_patch_info


def _IsIncrementalBuild(buildroot, clobber):
  """Returns True if we are reusing an existing buildroot."""
  repo_dir = os.path.join(buildroot, '.repo')
  return not clobber and os.path.isdir(repo_dir)


class Builder(object):
  """Parent class for all builder types.

  This class functions as a parent class for various build types.  It's intended
  use is builder_instance.Run().

  Vars:
    build_config:  The configuration dictionary from cbuildbot_config.
    options:  The options provided from optparse in main().
    completed_stages_file: Where we store resume state.
    archive_url:  Where our artifacts for this builder will be archived.
    tracking_branch: The tracking branch for this build.
    release_tag:  The associated "chrome os version" of this build.
    gerrit_patches: Gerrit patches to be included in build.
    local_patches: Local patches to be included in build.
  """

  def __init__(self, options, build_config):
    """Initializes instance variables. Must be called by all subclasses."""
    self.build_config = build_config
    self.options = options

    # TODO, Remove here and in config after bug chromium-os:14649 is fixed.
    if self.build_config['chromeos_official']:
      os.environ['CHROMEOS_OFFICIAL'] = '1'

    self.completed_stages_file = os.path.join(options.buildroot,
                                              '.completed_stages')
    self.archive_stages = {}
    self.archive_urls = {}
    self.release_tag = None
    self.tracking_branch = _GetChromiteTrackingBranch()
    self.gerrit_patches = None
    self.local_patches = None

  def Initialize(self):
    """Runs through the initialization steps of an actual build."""
    if self.options.resume and os.path.exists(self.completed_stages_file):
      with open(self.completed_stages_file, 'r') as load_file:
        results_lib.Results.RestoreCompletedStages(load_file)

    # We only want to do this if we need to patch changes.
    if not results_lib.Results.GetPrevious().get(
        self._GetStageInstance(stages.PatchChangesStage, None, None).name):
      self.gerrit_patches, self.local_patches = _PreProcessPatches(
          self.options.gerrit_patches, self.options.local_patches)

    bs.BuilderStage.SetTrackingBranch(self.tracking_branch)

    # Check branch matching early.
    if _IsIncrementalBuild(self.options.buildroot, self.options.clobber):
      _CheckBuildRootBranch(self.options.buildroot, self.tracking_branch)

    self._RunStage(stages.CleanUpStage)

  def _GetStageInstance(self, stage, *args, **kwargs):
    """Helper function to get an instance given the args.

    Useful as almost all stages just take in options and build_config.
    """
    config = kwargs.pop('config', self.build_config)
    return stage(self.options, config, *args, **kwargs)

  def _SetReleaseTag(self):
    """Sets the release tag from the manifest_manager.

    Must be run after sync stage as syncing enables us to have a release tag.
    """
    # Extract version we have decided to build into self.release_tag.
    manifest_manager = stages.ManifestVersionedSyncStage.manifest_manager
    if manifest_manager:
      self.release_tag = manifest_manager.current_version

  def _RunStage(self, stage, *args, **kwargs):
    """Wrapper to run a stage."""
    stage_instance = self._GetStageInstance(stage, *args, **kwargs)
    return stage_instance.Run()

  def GetSyncInstance(self):
    """Returns an instance of a SyncStage that should be run.

    Subclasses must override this method.
    """
    raise NotImplementedError()

  def RunStages(self):
    """Subclasses must override this method.  Runs the appropriate code."""
    raise NotImplementedError()

  def _WriteCheckpoint(self):
    """Drops a completed stages file with current state."""
    with open(self.completed_stages_file, 'w+') as save_file:
      results_lib.Results.SaveCompletedStages(save_file)

  def _ShouldReExecuteInBuildRoot(self):
    """Returns True if this build should be re-executed in the buildroot."""
    abs_buildroot = os.path.abspath(self.options.buildroot)
    return not os.path.abspath(__file__).startswith(abs_buildroot)

  def _ReExecuteInBuildroot(self, sync_instance):
    """Reexecutes self in buildroot and returns True if build succeeds.

    This allows the buildbot code to test itself when changes are patched for
    buildbot-related code.  This is a no-op if the buildroot == buildroot
    of the running chromite checkout.

    Args:
      sync_instance:  Instance of the sync stage that was run to sync.

    Returns:
      True if the Build succeeded.
    """
    # If we are resuming, use last checkpoint.
    if not self.options.resume:
      self._WriteCheckpoint()

    # Re-write paths to use absolute paths.
    # Suppress any timeout options given from the commandline in the
    # invoked cbuildbot; our timeout will enforce it instead.
    args_to_append = ['--resume', '--timeout', '0', '--buildroot',
                      os.path.abspath(self.options.buildroot)]

    if self.options.chrome_root:
      args_to_append += ['--chrome_root',
                         os.path.abspath(self.options.chrome_root)]

    if stages.ManifestVersionedSyncStage.manifest_manager:
      ver = stages.ManifestVersionedSyncStage.manifest_manager.current_version
      args_to_append += ['--version', ver]

    if isinstance(sync_instance, stages.CommitQueueSyncStage):
      vp_file = sync_instance.SaveValidationPool()
      args_to_append += ['--validation_pool', vp_file]

    # Re-run the command in the buildroot.
    # Finally, be generous and give the invoked cbuildbot 30s to shutdown
    # when something occurs.  It should exit quicker, but the sigterm may
    # hit while the system is particularly busy.
    return_obj = cros_lib.RunCommand(
        [_PATH_TO_CBUILDBOT] + sys.argv[1:] + args_to_append,
        cwd=self.options.buildroot, error_code_ok=True, kill_timeout=30)
    return return_obj.returncode == 0

  def Run(self):
    """Main runner for this builder class.  Runs build and prints summary."""
    print_report = True
    success = True
    try:
      self.Initialize()
      sync_instance = self.GetSyncInstance()
      sync_instance.Run()
      self._SetReleaseTag()

      if (self.gerrit_patches or self.local_patches
          or self.options.remote_patches):
        self._RunStage(stages.PatchChangesStage,
                       self.gerrit_patches, self.local_patches)

      if self._ShouldReExecuteInBuildRoot():
        print_report = False
        success = self._ReExecuteInBuildroot(sync_instance)
      else:
        self.RunStages()

    finally:
      if print_report:
        self._WriteCheckpoint()
        print '\n\n\n@@@BUILD_STEP Report@@@\n'
        results_lib.Results.Report(sys.stdout, self.archive_urls,
                                   self.release_tag)
        success = results_lib.Results.BuildSucceededSoFar()

    return success


class SimpleBuilder(Builder):
  """Builder that performs basic vetting operations."""

  def GetSyncInstance(self):
    """Sync to lkgm or TOT as necessary.

    Returns: the instance of the sync stage that was run.
    """
    if self.options.lkgm or self.build_config['use_lkgm']:
      sync_stage = self._GetStageInstance(stages.LKGMSyncStage)
    else:
      sync_stage = self._GetStageInstance(stages.SyncStage)

    return sync_stage

  def _RunBackgroundStagesForBoard(self, board):
    """Run background board-specific stages for the specified board."""
    archive_stage = self.archive_stages[board]
    configs = self.build_config['board_specific_configs']
    config = configs.get(board, self.build_config)
    stage_list = [[stages.VMTestStage, board, archive_stage],
                  [stages.ChromeTestStage, board, archive_stage],
                  [stages.UnitTestStage, board],
                  [stages.UploadPrebuiltsStage, board]]

    # We can not run hw tests without archiving the payloads.
    if self.options.archive:
      for suite in config['hw_tests']:
        stage_list.append([stages.HWTestStage, board, archive_stage, suite])

    steps = [self._GetStageInstance(*x, config=config).Run for x in stage_list]
    background.RunParallelSteps(steps + [archive_stage.Run])

  def RunStages(self):
    """Runs through build process."""
    self._RunStage(stages.BuildBoardStage)

    # TODO(sosa): Split these out into classes.
    if self.build_config['build_type'] == constants.CHROOT_BUILDER_TYPE:
      self._RunStage(stages.SDKTestStage)
      self._RunStage(stages.UploadPrebuiltsStage,
                     constants.CHROOT_BUILDER_BOARD)
    elif self.build_config['build_type'] == constants.REFRESH_PACKAGES_TYPE:
      self._RunStage(stages.RefreshPackageStatusStage)
    else:
      self._RunStage(stages.UprevStage)

      configs = self.build_config['board_specific_configs']
      for board in self.build_config['boards']:
        config = configs.get(board, self.build_config)
        archive_stage = self._GetStageInstance(stages.ArchiveStage, board,
                                               config=config)
        self.archive_stages[board] = archive_stage

      # Set up a process pool to run test/archive stages in the background.
      # This process runs task(board) for each board added to the queue.
      queue = multiprocessing.Queue()
      task = self._RunBackgroundStagesForBoard
      with background.BackgroundTaskRunner(queue, task):
        for board in self.build_config['boards']:
          # Run BuildTarget in the foreground.
          archive_stage = self.archive_stages[board]
          config = configs.get(board, self.build_config)
          self._RunStage(stages.BuildTargetStage, board, archive_stage,
                         config=config)
          self.archive_urls[board] = archive_stage.GetDownloadUrl()

          # Kick off task(board) in the background.
          queue.put([board])


class DistributedBuilder(SimpleBuilder):
  """Build class that has special logic to handle distributed builds.

  These builds sync using git/manifest logic in manifest_versions.  In general
  they use a non-distributed builder code for the bulk of the work.
  """
  def __init__(self, options, build_config):
    """Initializes a buildbot builder.

    Extra variables:
      completion_stage_class:  Stage used to complete a build.  Set in the Sync
        stage.
    """
    super(DistributedBuilder, self).__init__(options, build_config)
    self.completion_stage_class = None

  def GetSyncInstance(self):
    """Syncs the tree using one of the distributed sync logic paths.

    Returns: the instance of the sync stage that was run.
    """
    # Determine sync class to use.  CQ overrides PFQ bits so should check it
    # first.
    if cbuildbot_config.IsCQType(self.build_config['build_type']):
      sync_stage = self._GetStageInstance(stages.CommitQueueSyncStage)
      self.completion_stage_class = stages.CommitQueueCompletionStage
    elif cbuildbot_config.IsPFQType(self.build_config['build_type']):
      sync_stage = self._GetStageInstance(stages.LKGMCandidateSyncStage)
      self.completion_stage_class = stages.LKGMCandidateSyncCompletionStage
    else:
      sync_stage = self._GetStageInstance(stages.ManifestVersionedSyncStage)
      self.completion_stage_class = stages.ManifestVersionedSyncCompletionStage

    return sync_stage

  def Publish(self, was_build_successful):
    """Completes build by publishing any required information."""
    completion_stage = self._GetStageInstance(self.completion_stage_class,
                                              was_build_successful)
    completion_stage.Run()
    name = completion_stage.name
    if not results_lib.Results.WasStageSuccessful(name):
      should_publish_changes = False
    else:
      should_publish_changes = (self.build_config['master'] and
                                was_build_successful)

    if should_publish_changes:
      self._RunStage(stages.PublishUprevChangesStage)

  def RunStages(self):
    """Runs simple builder logic and publishes information to overlays."""
    was_build_successful = False
    try:
      super(DistributedBuilder, self).RunStages()
      was_build_successful = results_lib.Results.BuildSucceededSoFar()
    except SystemExit as ex:
      # If a stage calls sys.exit(0), it's exiting with success, so that means
      # we should mark ourselves as successful.
      if ex.code == 0:
        was_build_successful = True
      raise
    finally:
      self.Publish(was_build_successful)


def _ConfirmBuildRoot(buildroot):
  """Confirm with user the inferred buildroot, and mark it as confirmed."""
  warning = 'Using default directory %s as buildroot' % buildroot
  response = cros_lib.YesNoPrompt(default=cros_lib.NO, warning=warning,
                                  full=True)
  if response == cros_lib.NO:
    print('Please specify a buildroot with the --buildroot option.')
    sys.exit(0)

  if not os.path.exists(buildroot):
    os.mkdir(buildroot)

  repository.CreateTrybotMarker(buildroot)


def _DetermineDefaultBuildRoot(internal_build):
  """Default buildroot to be under the directory that contains current checkout.

  Arguments:
    internal_build: Whether the build is an internal build
  """
  repo_dir = cros_lib.FindRepoDir()
  if not repo_dir:
    cros_lib.Die('Could not find root of local checkout.  Please specify'
                 'using --buildroot option.')

  # Place trybot buildroot under the directory containing current checkout.
  top_level = os.path.dirname(os.path.realpath(os.path.dirname(repo_dir)))
  if internal_build:
    buildroot = os.path.join(top_level, _DEFAULT_INT_BUILDROOT)
  else:
    buildroot = os.path.join(top_level, _DEFAULT_EXT_BUILDROOT)

  return buildroot


def _BackupPreviousLog(log_file, backup_limit=25):
  """Rename previous log.

  Args:
    log_file: The absolute path to the previous log.
  """
  if os.path.exists(log_file):
    old_logs = sorted(glob.glob(log_file + '.*'),
                      key=distutils.version.LooseVersion)

    if len(old_logs) >= backup_limit:
      os.remove(old_logs[0])

    last = 0
    if old_logs:
      last = int(old_logs.pop().rpartition('.')[2])

    os.rename(log_file, log_file + '.' + str(last + 1))


def _RunBuildStagesWrapper(options, build_config):
  """Helper function that wraps RunBuildStages()."""
  def IsDistributedBuilder():
    """Determines whether the build_config should be a DistributedBuilder."""
    if not options.buildbot:
      return False
    elif build_config['build_type'] in _DISTRIBUTED_TYPES:
      chrome_rev = build_config['chrome_rev']
      if options.chrome_rev: chrome_rev = options.chrome_rev
      # We don't do distributed logic to TOT Chrome PFQ's, nor local
      # chrome roots (e.g. chrome try bots)
      if chrome_rev not in [constants.CHROME_REV_TOT,
                            constants.CHROME_REV_LOCAL,
                            constants.CHROME_REV_SPEC]:
        return True

    return False

  # Start tee-ing output to file.
  log_file = None
  if options.tee:
    default_dir = os.path.join(options.buildroot, _DEFAULT_LOG_DIR)
    dirname = options.log_dir or default_dir
    log_file = os.path.join(dirname, _BUILDBOT_LOG_FILE)

    cros_lib.SafeMakedirs(dirname)
    _BackupPreviousLog(log_file)

  try:
    with cros_lib.AllowDisabling(options.tee, tee.Tee, log_file):
      cros_lib.Info("cbuildbot executed with args %s"
                    % ' '.join(map(repr, sys.argv)))
      if IsDistributedBuilder():
        buildbot = DistributedBuilder(options, build_config)
      else:
        buildbot = SimpleBuilder(options, build_config)

      if not buildbot.Run():
        sys.exit(1)
  finally:
    if options.tee:
      cros_lib.Info('Output should be saved to %s' % log_file)


# Parser related functions
def _CheckLocalPatches(local_patches):
  """Do an early quick check of the passed-in patches.

  If the branch of a project is not specified we append the current branch the
  project is on.
  """
  verified_patches = []
  for patch in local_patches:
    components = patch.split(':')
    if len(components) > 2:
      msg = 'Specify local patches in project[:branch] format.'
      raise optparse.OptionValueError(msg)

    # validate project
    project = components[0]
    if not cros_lib.DoesProjectExist('.', project):
      raise optparse.OptionValueError('Project %s does not exist.' % project)

    project_dir = cros_lib.GetProjectDir('.', project)

    # If no branch was specified, we use the project's current branch.
    if len(components) == 1:
      branch = cros_lib.GetCurrentBranch(project_dir)
      if not branch:
        raise optparse.OptionValueError('project %s is not on a branch!'
                                        % project)
      # Append branch information to patch
      patch = '%s:%s' % (project, branch)
    else:
      branch = components[1]
      if not cros_lib.DoesLocalBranchExist(project_dir, branch):
        raise optparse.OptionValueError('Project %s does not have branch %s'
                                        % (project, branch))

    verified_patches.append(patch)

  return verified_patches


def _CheckBuildRootOption(_option, _opt_str, value, parser):
  """Validate and convert buildroot to full-path form."""
  value = value.strip()
  if not value or value == '/':
    raise optparse.OptionValueError('Invalid buildroot specified')

  parser.values.buildroot = os.path.realpath(os.path.expanduser(value))


def _CheckLogDirOption(_option, _opt_str, value, parser):
  """Validate and convert buildroot to full-path form."""
  parser.values.log_dir = os.path.abspath(os.path.expanduser(value))


def _CheckChromeVersionOption(_option, _opt_str, value, parser):
  """Upgrade other options based on chrome_version being passed."""
  value = value.strip()

  if parser.values.chrome_rev is None and value:
    parser.values.chrome_rev = constants.CHROME_REV_SPEC

  parser.values.chrome_version = value


def _CheckChromeRootOption(_option, _opt_str, value, parser):
  """Validate and convert chrome_root to full-path form."""
  value = value.strip()
  if not value or value == '/':
    raise optparse.OptionValueError('Invalid chrome_root specified')

  if parser.values.chrome_rev is None:
    parser.values.chrome_rev = constants.CHROME_REV_LOCAL

  parser.values.chrome_root = os.path.realpath(os.path.expanduser(value))


def _CheckChromeRevOption(_option, _opt_str, value, parser):
  """Validate the chrome_rev option."""
  value = value.strip()
  if value not in constants.VALID_CHROME_REVISIONS:
    raise optparse.OptionValueError('Invalid chrome rev specified')

  parser.values.chrome_rev = value


def _CreateParser():
  """Generate and return the parser with all the options."""
  # Parse options
  usage = "usage: %prog [options] buildbot_config"
  parser = optparse.OptionParser(usage=usage)

  # Main options
  parser.add_option('-a', '--all', action='store_true', dest='print_all',
                    default=False,
                    help=('List all of the buildbot configs available. Use '
                          'with the --list option'))
  parser.add_option('-r', '--buildroot', action='callback', dest='buildroot',
                    type='string', callback=_CheckBuildRootOption,
                    help=('Root directory where source is checked out to, and '
                          'where the build occurs. For external build configs, '
                          "defaults to 'trybot' directory at top level of your "
                          'repo-managed checkout.'))
  parser.add_option('--chrome_rev', default=None, type='string',
                    action='callback', dest='chrome_rev',
                    callback=_CheckChromeRevOption,
                    help=('Revision of Chrome to use, of type '
                          '[%s]' % '|'.join(constants.VALID_CHROME_REVISIONS)))
  parser.add_option('-g', '--gerrit-patches', action='append', default=[],
                    type='string', metavar="'Id1 *int_Id2...IdN'",
                    help=("Space-separated list of short-form Gerrit "
                          "Change-Id's or change numbers to patch.  Please "
                          "prepend '*' to internal Change-Id's"))
  parser.add_option('-l', '--list', action='store_true', dest='list',
                    default=False,
                    help=('List the suggested trybot configs to use.  Use '
                          '--all to list all of the available configs.'))
  parser.add_option('-p', '--local-patches', action='append', default=[],
                    metavar="'<project1>[:<branch1>]...<projectN>[:<branchN>]'",
                    help=('Space-separated list of project branches with '
                          'patches to apply.  Projects are specified by name. '
                          'If no branch is specified the current branch of the '
                          'project will be used.'))
  parser.add_option('--profile', default=None, type='string', action='store',
                    dest='profile',
                    help=('Name of profile to sub-specify board variant.'))
  parser.add_option('--remote', default=False, action='store_true',
                    help=('Specifies that this tryjob should be run remotely.'))

  # Advanced options
  group = optparse.OptionGroup(
      parser,
      'Advanced Options',
      'Caution: use these options at your own risk.')

  group.add_option('--buildbot', dest='buildbot', action='store_true',
                    default=False, help='This is running on a buildbot')
  group.add_option('--buildnumber',
                   help='build number', type='int', default=0)
  group.add_option('--chrome_root', default=None, type='string',
                    action='callback', dest='chrome_root',
                    callback=_CheckChromeRootOption,
                    help='Local checkout of Chrome to use.')
  group.add_option('--chrome_version', default=None, type='string',
                   action='callback', dest='chrome_version',
                   callback=_CheckChromeVersionOption,
                   help='Used with SPEC logic to force a particular SVN '
                        'revision of chrome rather than the latest.')
  group.add_option('--clobber', action='store_true', dest='clobber',
                    default=False,
                    help='Clears an old checkout before syncing')
  group.add_option('--lkgm', action='store_true', dest='lkgm', default=False,
                    help='Sync to last known good manifest blessed by PFQ')
  parser.add_option('--log_dir', action='callback', dest='log_dir',
                    type='string', callback=_CheckLogDirOption,
                    help=('Directory where logs are stored.'))
  group.add_option('--maxarchives', dest='max_archive_builds',
                    default=3, type='int',
                    help="Change the local saved build count limit.")
  group.add_option('--noarchive', action='store_false', dest='archive',
                    default=True,
                    help="Don't run archive stage.")
  group.add_option('--nobuild', action='store_false', dest='build',
                    default=True,
                    help="Don't actually build (for cbuildbot dev")
  group.add_option('--noclean', action='store_false', dest='clean',
                    default=True,
                    help="Don't clean the buildroot")
  group.add_option('--noprebuilts', action='store_false', dest='prebuilts',
                    default=True,
                    help="Don't upload prebuilts.")
  group.add_option('--nosync', action='store_false', dest='sync',
                    default=True,
                    help="Don't sync before building.")
  group.add_option('--nocgroups', action='store_false', dest='cgroups',
                    default=True,
                    help='Disable cbuildbots usage of cgroups.')
  group.add_option('--notests', action='store_false', dest='tests',
                    default=True,
                    help='Override values from buildconfig and run no tests.')
  group.add_option('--nouprev', action='store_false', dest='uprev',
                    default=True,
                    help='Override values from buildconfig and never uprev.')
  group.add_option('--reference-repo', action='store', default=None,
                    dest='reference_repo',
                    help='Reuse git data stored in an existing repo '
                         'checkout. This can drastically reduce the network '
                         'time spent setting up the trybot checkout.  By '
                         "default, if this option isn't given but cbuildbot "
                         'is invoked from a repo checkout, cbuildbot will '
                         'use the repo root.')
  # Indicates this is running on a remote trybot machine.  '
  group.add_option('--remote-trybot', dest='remote_trybot', action='store_true',
                    default=False, help=optparse.SUPPRESS_HELP)
  # Patches uploaded by trybot client when run using the -p option.
  group.add_option('--remote-patches', action='append', default=[],
                   help=optparse.SUPPRESS_HELP)
  group.add_option('--resume', action='store_true', default=False,
                    help='Skip stages already successfully completed.')
  group.add_option('--timeout', action='store', type='int', default=0,
                    help="Specify the maximum amount of time this job can run "
                         "for, at which point the build will be aborted.  If "
                         "set to zero, then there is no timeout")
  group.add_option('--validation_pool', default=None,
                   help='Path to a pickled validation pool. Intended for use '
                   'only with the commit queue.')
  group.add_option('--version', dest='force_version', default=None,
                   help='Used with manifest logic.  Forces use of this version '
                        'rather than create or get latest.')

  parser.add_option_group(group)

  # Debug options
  group = optparse.OptionGroup(parser, "Debug Options")

  group.add_option('--debug', action='store_true', default=None,
                    help='Override some options to run as a developer.')
  group.add_option('--dump_config', action='store_true', dest='dump_config',
                    default=False,
                    help='Dump out build config options, and exit.')
  group.add_option('--notee', action='store_false', dest='tee', default=True,
                    help="Disable logging and internal tee process.  Primarily "
                         "used for debugging cbuildbot itself.")
  parser.add_option_group(group)
  return parser


def _FinishParsing(options, args):
  """Perform some parsing tasks that need to take place after optparse.

  This function needs to be easily testable!  Keep it free of
  environment-dependent code.  Put more detailed usage validation in
  _PostParseCheck().

  Args:
    options, args: The options/args object returned by optparse
  """
  if options.chrome_root:
    if options.chrome_rev != constants.CHROME_REV_LOCAL:
      cros_lib.Die('Chrome rev must be %s if chrome_root is set.' %
                   constants.CHROME_REV_LOCAL)
  else:
    if options.chrome_rev == constants.CHROME_REV_LOCAL:
      cros_lib.Die('Chrome root must be set if chrome_rev is %s.' %
                   constants.CHROME_REV_LOCAL)

  if options.chrome_version:
    if options.chrome_rev != constants.CHROME_REV_SPEC:
      cros_lib.Die('Chrome rev must be %s if chrome_version is set.' %
                   constants.CHROME_REV_SPEC)
  else:
    if options.chrome_rev == constants.CHROME_REV_SPEC:
      cros_lib.Die('Chrome rev must not be %s if chrome_version is not set.' %
                   constants.CHROME_REV_SPEC)

  if options.remote and not (options.gerrit_patches or options.local_patches):
    cros_lib.Die('Must provide patches when running with --remote.')

  if len(args) > 1 and not options.remote:
    cros_lib.Die('Multiple configs not supported if not running with --remote.')

  if options.buildbot and options.remote_trybot:
    cros_lib.Die('--buildbot and --remote-trybot cannot be used together.')

  # Record whether --debug was set explicitly vs. it was inferred.
  options.debug_forced = False
  if options.debug:
    options.debug_forced = True
  else:
    # We don't set debug by default for
    # 1. --buildbot invocations.
    # 2. --remote invocations, because it needs to push changes to the tryjob
    #    repo.
    options.debug = not options.buildbot and not options.remote


def _SplitAndFlatten(appended_items):
  """Given a list of space-separated items, split into flattened list.

  Given ['abc def', 'hij'] return ['abc', 'def', 'hij'].
  Arguments:
    appended_items: List of delimiter-separated items.

  Returns: Flattened list.
  """
  new_list = []
  for item in appended_items:
    new_list.extend(item.split())
  return new_list


def _PostParseCheck(options, args):
  """Perform some usage validation after we've parsed the arguments

  Args:
    options/args: The options/args object returned by optparse
  """
  if not options.resume:
    options.gerrit_patches = _SplitAndFlatten(options.gerrit_patches)
    options.remote_patches = _SplitAndFlatten(options.remote_patches)
    try:
      # TODO(rcui): Split this into two stages, one that parses, another that
      # validates.  Parsing step will be called by _FinishParsing().
      options.local_patches = _CheckLocalPatches(
          _SplitAndFlatten(options.local_patches))
    except optparse.OptionValueError as e:
      cros_lib.Die(str(e))


def _ParseCommandLine(parser, argv):
  """Completely parse the commandline arguments"""
  (options, args) = parser.parse_args(argv)
  # Strip out null arguments.
  # TODO(rcui): Remove when buildbot is fixed
  args = [arg for arg in args if arg]
  _FinishParsing(options, args)
  return options, args


def main(argv):
  # Set umask to 022 so files created by buildbot are readable.
  os.umask(022)

  if cros_lib.IsInsideChroot():
    cros_lib.Die('Please run cbuildbot from outside the chroot.')

  parser = _CreateParser()
  (options, args) = _ParseCommandLine(parser, argv)

  if options.list:
    _PrintValidConfigs(not options.print_all)
    sys.exit(0)

  _PostParseCheck(options, args)

  if options.remote:
    cros_lib.DebugLevel.SetDebugLevel(cros_lib.DebugLevel.WARNING)

    # Verify configs are valid.
    for bot in args:
      _GetConfig(bot)

    # Verify gerrit patches are valid.
    print 'Verifying patches...'
    _, local_patches = _PreProcessPatches(options.gerrit_patches,
                                          options.local_patches)
    print 'Submitting tryjob...'
    tryjob = remote_try.RemoteTryJob(options, args, local_patches)
    tryjob.Submit(dryrun=options.debug)
    print 'Tryjob submitted!'
    print ('Go to %s to view the status of your job.'
           % tryjob.GetTrybotConsoleLink())
    sys.exit(0)

  if args:
    # Only expecting one config
    bot_id = args[-1]
    build_config = _GetConfig(bot_id)
  else:
    parser.error('Invalid usage.  Use -h to see usage.')

  if options.reference_repo is None:
    repo_path = os.path.join(constants.SOURCE_ROOT, '.repo')
    # If we're being run from a repo checkout, reuse the repo's git pool to
    # cut down on sync time.
    if os.path.exists(repo_path):
      options.reference_repo = constants.SOURCE_ROOT
  elif options.reference_repo:
    if not os.path.exists(options.reference_repo):
      parser.error('Reference path %s does not exist'
                   % (options.reference_repo,))
    elif not os.path.exists(os.path.join(options.reference_repo, '.repo')):
      parser.error('Reference path %s does not look to be the base of a '
                   'repo checkout; no .repo exists in the root.'
                   % (options.reference_repo,))
  if options.buildbot:
    if not options.cgroups:
      parser.error('Options --buildbot and --nocgroups cannot be used '
                   'together.  Cgroup support is required for buildbot mode.')
    if not cgroups.Cgroup.CgroupsSupported():
      parser.error('Option --buildbot was given, but this system does not '
                   'support cgroups.   Failing.')

    missing = []
    for program in _BUILDBOT_REQUIRED_BINARIES:
      ret = cros_lib.RunCommand('which %s' % program, shell=True,
                                redirect_stderr=True, redirect_stdout=True,
                                error_code_ok=True, print_cmd=False)
      if ret.returncode != 0:
        missing.append(program)

    if missing:
      parser.error("Option --buildbot requires the following binaries which "
                   "couldn't be found in $PATH: %s"
                   % (', '.join(missing)))

  if options.reference_repo:
    options.reference_repo = os.path.abspath(options.reference_repo)

  if options.dump_config:
    # This works, but option ordering is bad...
    print 'Configuration %s:' % bot_id
    pretty_printer = pprint.PrettyPrinter(indent=2)
    pretty_printer.pprint(build_config)
    sys.exit(0)

  if not options.buildroot:
    if options.buildbot:
      parser.error('Please specify a buildroot with the --buildroot option.')
    options.buildroot = _DetermineDefaultBuildRoot(build_config['internal'])
    # We use a marker file in the buildroot to indicate the user has
    # consented to using this directory.
    if not os.path.exists(repository.GetTrybotMarkerPath(options.buildroot)):
      _ConfirmBuildRoot(options.buildroot)

  # Sanity check of buildroot- specifically that it's not pointing into the
  # midst of an existing repo since git-repo doesn't support nesting.
  if (not repository.IsARepoRoot(options.buildroot) and
      repository.InARepoRepository(options.buildroot)):
    parser.error('Configured buildroot %s points into a repository checkout, '
                 'rather than the root of it.  This is not supported.'
                 % options.buildroot)

  with cleanup.EnforcedCleanupSection() as critical_section:
    with sudo.SudoKeepAlive():
      with cros_lib.AllowDisabling(options.cgroups,
                                   cgroups.SimpleContainChildren, 'cbuildbot'):
        # Mark everything between EnforcedCleanupSection and here as having to
        # be rolled back via the contextmanager cleanup handlers.  This ensures
        # that sudo bits cannot outlive cbuildbot, that anything cgroups
        # would kill gets killed, etc.
        critical_section.ForkWatchdog()

        with cros_lib.AllowDisabling(options.timeout > 0,
                                     cros_lib.Timeout, options.timeout):
          if not options.buildbot:
            build_config = cbuildbot_config.OverrideConfigForTrybot(
                build_config,
                options.remote_trybot)

          _RunBuildStagesWrapper(options, build_config)