Make a directory in which to put bisect-related modules.

BUG=

Review URL: https://codereview.chromium.org/359013002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282209 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 909 insertions, 0 deletions

diff --git a/tools/auto_bisect/OWNERS b/tools/auto_bisect/OWNERS
new file mode 100644
index 0000000..a450d85
--- /dev/null
+++ b/tools/auto_bisect/OWNERS
@@ -0,0 +1,4 @@
+prasadv@chromium.org
+qyearsley@chromium.org
+simonhatch@chromium.org
+tonyg@chromium.org
diff --git a/tools/auto_bisect/README b/tools/auto_bisect/README
new file mode 100644
index 0000000..d43222c
--- /dev/null
+++ b/tools/auto_bisect/README
@@ -0,0 +1,23 @@
+This directory contains modules related to tools for bisecting regressions.
+
+There are several different tools for bisecting regressions; the main use
+of these tools is to find revisions where a performance regression occurred.
+These tools are generally run by trybots but can also be run locally.
+
+Documentation:
+  http://www.chromium.org/developers/bisecting-bugs
+  http://www.chromium.org/developers/tree-sheriffs/perf-sheriffs/bisecting-performance-regressions
+
+Overview of bisect-related files in src/tools:
+  run-bisect-perf-regression.py
+     -- the script used to kick off a normal performance regression bisect job.
+  run-bisect-perf-regression.cfg
+     -- this file contains parameters for a bisect job, and is read by other
+        modules including run-bisect-perf-regresion.py.
+  run-bisect-manual-test.py
+     -- a script which is used to manually bisect regressions; this also
+        depends on bisect-perf-gression.py.
+  bisect-perf-regression.py
+     -- the main module which the others depend on.
+  bisect-manual-test.py
+     -- a helper module used when manually bisect regressions.
diff --git a/tools/auto_bisect/__init__.py b/tools/auto_bisect/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tools/auto_bisect/__init__.py
diff --git a/tools/auto_bisect/bisect_utils.py b/tools/auto_bisect/bisect_utils.py
new file mode 100644
index 0000000..7dc9a9b
--- /dev/null
+++ b/tools/auto_bisect/bisect_utils.py
@@ -0,0 +1,510 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Set of operations/utilities related to checking out the depot, and
+outputting annotations on the buildbot waterfall. These are intended to be
+used by the bisection scripts."""
+
+import errno
+import imp
+import os
+import shutil
+import stat
+import subprocess
+import sys
+
+DEFAULT_GCLIENT_CUSTOM_DEPS = {
+    "src/data/page_cycler": "https://chrome-internal.googlesource.com/"
+                            "chrome/data/page_cycler/.git",
+    "src/data/dom_perf": "https://chrome-internal.googlesource.com/"
+                         "chrome/data/dom_perf/.git",
+    "src/data/mach_ports": "https://chrome-internal.googlesource.com/"
+                           "chrome/data/mach_ports/.git",
+    "src/tools/perf/data": "https://chrome-internal.googlesource.com/"
+                           "chrome/tools/perf/data/.git",
+    "src/third_party/adobe/flash/binaries/ppapi/linux":
+        "https://chrome-internal.googlesource.com/"
+        "chrome/deps/adobe/flash/binaries/ppapi/linux/.git",
+    "src/third_party/adobe/flash/binaries/ppapi/linux_x64":
+        "https://chrome-internal.googlesource.com/"
+        "chrome/deps/adobe/flash/binaries/ppapi/linux_x64/.git",
+    "src/third_party/adobe/flash/binaries/ppapi/mac":
+        "https://chrome-internal.googlesource.com/"
+        "chrome/deps/adobe/flash/binaries/ppapi/mac/.git",
+    "src/third_party/adobe/flash/binaries/ppapi/mac_64":
+        "https://chrome-internal.googlesource.com/"
+        "chrome/deps/adobe/flash/binaries/ppapi/mac_64/.git",
+    "src/third_party/adobe/flash/binaries/ppapi/win":
+        "https://chrome-internal.googlesource.com/"
+        "chrome/deps/adobe/flash/binaries/ppapi/win/.git",
+    "src/third_party/adobe/flash/binaries/ppapi/win_x64":
+        "https://chrome-internal.googlesource.com/"
+        "chrome/deps/adobe/flash/binaries/ppapi/win_x64/.git",
+    "src/chrome/tools/test/reference_build/chrome_win": None,
+    "src/chrome/tools/test/reference_build/chrome_mac": None,
+    "src/chrome/tools/test/reference_build/chrome_linux": None,
+    "src/third_party/WebKit/LayoutTests": None,
+    "src/tools/valgrind": None,}
+
+GCLIENT_SPEC_DATA = [
+  { "name"        : "src",
+    "url"         : "https://chromium.googlesource.com/chromium/src.git",
+    "deps_file"   : ".DEPS.git",
+    "managed"     : True,
+    "custom_deps" : {},
+    "safesync_url": "",
+  },
+]
+GCLIENT_SPEC_ANDROID = "\ntarget_os = ['android']"
+GCLIENT_CUSTOM_DEPS_V8 = {"src/v8_bleeding_edge": "git://github.com/v8/v8.git"}
+FILE_DEPS_GIT = '.DEPS.git'
+FILE_DEPS = 'DEPS'
+
+REPO_PARAMS = [
+  'https://chrome-internal.googlesource.com/chromeos/manifest-internal/',
+  '--repo-url',
+  'https://git.chromium.org/external/repo.git'
+]
+
+REPO_SYNC_COMMAND = 'git checkout -f $(git rev-list --max-count=1 '\
+                    '--before=%d remotes/m/master)'
+
+ORIGINAL_ENV = {}
+
+def OutputAnnotationStepStart(name):
+  """Outputs appropriate annotation to signal the start of a step to
+  a trybot.
+
+  Args:
+    name: The name of the step.
+  """
+  print
+  print '@@@SEED_STEP %s@@@' % name
+  print '@@@STEP_CURSOR %s@@@' % name
+  print '@@@STEP_STARTED@@@'
+  print
+  sys.stdout.flush()
+
+
+def OutputAnnotationStepClosed():
+  """Outputs appropriate annotation to signal the closing of a step to
+  a trybot."""
+  print
+  print '@@@STEP_CLOSED@@@'
+  print
+  sys.stdout.flush()
+
+
+def OutputAnnotationStepLink(label, url):
+  """Outputs appropriate annotation to print a link.
+
+  Args:
+    label: The name to print.
+    url: The url to print.
+  """
+  print
+  print '@@@STEP_LINK@%s@%s@@@' % (label, url)
+  print
+  sys.stdout.flush()
+
+
+def LoadExtraSrc(path_to_file):
+  """Attempts to load an extra source file. If this is successful, uses the
+  new module to override some global values, such as gclient spec data.
+
+  Returns:
+    The loaded src module, or None."""
+  try:
+    global GCLIENT_SPEC_DATA
+    global GCLIENT_SPEC_ANDROID
+    extra_src = imp.load_source('data', path_to_file)
+    GCLIENT_SPEC_DATA = extra_src.GetGClientSpec()
+    GCLIENT_SPEC_ANDROID = extra_src.GetGClientSpecExtraParams()
+    return extra_src
+  except ImportError, e:
+    return None
+
+
+def IsTelemetryCommand(command):
+  """Attempts to discern whether or not a given command is running telemetry."""
+  return ('tools/perf/run_' in command or 'tools\\perf\\run_' in command)
+
+
+def CreateAndChangeToSourceDirectory(working_directory):
+  """Creates a directory 'bisect' as a subdirectory of 'working_directory'.  If
+  the function is successful, the current working directory will change to that
+  of the new 'bisect' directory.
+
+  Returns:
+    True if the directory was successfully created (or already existed).
+  """
+  cwd = os.getcwd()
+  os.chdir(working_directory)
+  try:
+    os.mkdir('bisect')
+  except OSError, e:
+    if e.errno != errno.EEXIST:
+      return False
+  os.chdir('bisect')
+  return True
+
+
+def SubprocessCall(cmd, cwd=None):
+  """Runs a subprocess with specified parameters.
+
+  Args:
+    params: A list of parameters to pass to gclient.
+    cwd: Working directory to run from.
+
+  Returns:
+    The return code of the call.
+  """
+  if os.name == 'nt':
+    # "HOME" isn't normally defined on windows, but is needed
+    # for git to find the user's .netrc file.
+    if not os.getenv('HOME'):
+      os.environ['HOME'] = os.environ['USERPROFILE']
+  shell = os.name == 'nt'
+  return subprocess.call(cmd, shell=shell, cwd=cwd)
+
+
+def RunGClient(params, cwd=None):
+  """Runs gclient with the specified parameters.
+
+  Args:
+    params: A list of parameters to pass to gclient.
+    cwd: Working directory to run from.
+
+  Returns:
+    The return code of the call.
+  """
+  cmd = ['gclient'] + params
+
+  return SubprocessCall(cmd, cwd=cwd)
+
+
+def RunRepo(params):
+  """Runs cros repo command with specified parameters.
+
+  Args:
+    params: A list of parameters to pass to gclient.
+
+  Returns:
+    The return code of the call.
+  """
+  cmd = ['repo'] + params
+
+  return SubprocessCall(cmd)
+
+
+def RunRepoSyncAtTimestamp(timestamp):
+  """Syncs all git depots to the timestamp specified using repo forall.
+
+  Args:
+    params: Unix timestamp to sync to.
+
+  Returns:
+    The return code of the call.
+  """
+  repo_sync = REPO_SYNC_COMMAND % timestamp
+  cmd = ['forall', '-c', REPO_SYNC_COMMAND % timestamp]
+  return RunRepo(cmd)
+
+
+def RunGClientAndCreateConfig(opts, custom_deps=None, cwd=None):
+  """Runs gclient and creates a config containing both src and src-internal.
+
+  Args:
+    opts: The options parsed from the command line through parse_args().
+    custom_deps: A dictionary of additional dependencies to add to .gclient.
+    cwd: Working directory to run from.
+
+  Returns:
+    The return code of the call.
+  """
+  spec = GCLIENT_SPEC_DATA
+
+  if custom_deps:
+    for k, v in custom_deps.iteritems():
+      spec[0]['custom_deps'][k] = v
+
+  # Cannot have newlines in string on windows
+  spec = 'solutions =' + str(spec)
+  spec = ''.join([l for l in spec.splitlines()])
+
+  if 'android' in opts.target_platform:
+    spec += GCLIENT_SPEC_ANDROID
+
+  return_code = RunGClient(
+      ['config', '--spec=%s' % spec, '--git-deps'], cwd=cwd)
+  return return_code
+
+
+def IsDepsFileBlink():
+  """Reads .DEPS.git and returns whether or not we're using blink.
+
+  Returns:
+    True if blink, false if webkit.
+  """
+  locals = {'Var': lambda _: locals["vars"][_],
+            'From': lambda *args: None}
+  execfile(FILE_DEPS_GIT, {}, locals)
+  return 'blink.git' in locals['vars']['webkit_url']
+
+
+def OnAccessError(func, path, exc_info):
+  """
+  Source: http://stackoverflow.com/questions/2656322/python-shutil-rmtree-fails-on-windows-with-access-is-denied
+
+  Error handler for ``shutil.rmtree``.
+
+  If the error is due to an access error (read only file)
+  it attempts to add write permission and then retries.
+
+  If the error is for another reason it re-raises the error.
+
+  Args:
+    func: The function that raised the error.
+    path: The path name passed to func.
+    exc_info: Exception information returned by sys.exc_info().
+  """
+  if not os.access(path, os.W_OK):
+    # Is the error an access error ?
+    os.chmod(path, stat.S_IWUSR)
+    func(path)
+  else:
+    raise
+
+
+def RemoveThirdPartyDirectory(dir_name):
+  """Removes third_party directory from the source.
+
+  At some point, some of the third_parties were causing issues to changes in
+  the way they are synced. We remove such folder in order to avoid sync errors
+  while bisecting.
+
+  Returns:
+    True on success, otherwise False.
+  """
+  path_to_dir = os.path.join(os.getcwd(), 'third_party', dir_name)
+  try:
+    if os.path.exists(path_to_dir):
+      shutil.rmtree(path_to_dir, onerror=OnAccessError)
+  except OSError, e:
+    print 'Error #%d while running shutil.rmtree(%s): %s' % (
+        e.errno, path_to_dir, str(e))
+    if e.errno != errno.ENOENT:
+      return False
+  return True
+
+
+def _CleanupPreviousGitRuns():
+  """Performs necessary cleanup between runs."""
+  # If a previous run of git crashed, bot was reset, etc... we
+  # might end up with leftover index.lock files.
+  for (path, dir, files) in os.walk(os.getcwd()):
+    for cur_file in files:
+      if cur_file.endswith('index.lock'):
+        path_to_file = os.path.join(path, cur_file)
+        os.remove(path_to_file)
+
+
+def RunGClientAndSync(cwd=None):
+  """Runs gclient and does a normal sync.
+
+  Args:
+    cwd: Working directory to run from.
+
+  Returns:
+    The return code of the call.
+  """
+  params = ['sync', '--verbose', '--nohooks', '--reset', '--force']
+  return RunGClient(params, cwd=cwd)
+
+
+def SetupGitDepot(opts, custom_deps):
+  """Sets up the depot for the bisection. The depot will be located in a
+  subdirectory called 'bisect'.
+
+  Args:
+    opts: The options parsed from the command line through parse_args().
+    custom_deps: A dictionary of additional dependencies to add to .gclient.
+
+  Returns:
+    True if gclient successfully created the config file and did a sync, False
+    otherwise.
+  """
+  name = 'Setting up Bisection Depot'
+
+  if opts.output_buildbot_annotations:
+    OutputAnnotationStepStart(name)
+
+  passed = False
+
+  if not RunGClientAndCreateConfig(opts, custom_deps):
+    passed_deps_check = True
+    if os.path.isfile(os.path.join('src', FILE_DEPS_GIT)):
+      cwd = os.getcwd()
+      os.chdir('src')
+      if not IsDepsFileBlink():
+        passed_deps_check = RemoveThirdPartyDirectory('Webkit')
+      else:
+        passed_deps_check = True
+      if passed_deps_check:
+        passed_deps_check = RemoveThirdPartyDirectory('libjingle')
+      if passed_deps_check:
+        passed_deps_check = RemoveThirdPartyDirectory('skia')
+      os.chdir(cwd)
+
+    if passed_deps_check:
+      _CleanupPreviousGitRuns()
+
+      RunGClient(['revert'])
+      if not RunGClientAndSync():
+        passed = True
+
+  if opts.output_buildbot_annotations:
+    print
+    OutputAnnotationStepClosed()
+
+  return passed
+
+
+def SetupCrosRepo():
+  """Sets up cros repo for bisecting chromeos.
+
+  Returns:
+    Returns 0 on success.
+  """
+  cwd = os.getcwd()
+  try:
+    os.mkdir('cros')
+  except OSError, e:
+    if e.errno != errno.EEXIST:
+      return False
+  os.chdir('cros')
+
+  cmd = ['init', '-u'] + REPO_PARAMS
+
+  passed = False
+
+  if not RunRepo(cmd):
+    if not RunRepo(['sync']):
+      passed = True
+  os.chdir(cwd)
+
+  return passed
+
+
+def CopyAndSaveOriginalEnvironmentVars():
+  """Makes a copy of the current environment variables."""
+  # TODO: Waiting on crbug.com/255689, will remove this after.
+  vars_to_remove = []
+  for k, v in os.environ.iteritems():
+    if 'ANDROID' in k:
+      vars_to_remove.append(k)
+  vars_to_remove.append('CHROME_SRC')
+  vars_to_remove.append('CHROMIUM_GYP_FILE')
+  vars_to_remove.append('GYP_CROSSCOMPILE')
+  vars_to_remove.append('GYP_DEFINES')
+  vars_to_remove.append('GYP_GENERATORS')
+  vars_to_remove.append('GYP_GENERATOR_FLAGS')
+  vars_to_remove.append('OBJCOPY')
+  for k in vars_to_remove:
+    if os.environ.has_key(k):
+      del os.environ[k]
+
+  global ORIGINAL_ENV
+  ORIGINAL_ENV = os.environ.copy()
+
+
+def SetupAndroidBuildEnvironment(opts, path_to_src=None):
+  """Sets up the android build environment.
+
+  Args:
+    opts: The options parsed from the command line through parse_args().
+    path_to_src: Path to the src checkout.
+
+  Returns:
+    True if successful.
+  """
+
+  # Revert the environment variables back to default before setting them up
+  # with envsetup.sh.
+  env_vars = os.environ.copy()
+  for k, _ in env_vars.iteritems():
+    del os.environ[k]
+  for k, v in ORIGINAL_ENV.iteritems():
+    os.environ[k] = v
+
+  path_to_file = os.path.join('build', 'android', 'envsetup.sh')
+  proc = subprocess.Popen(['bash', '-c', 'source %s && env' % path_to_file],
+                           stdout=subprocess.PIPE,
+                           stderr=subprocess.PIPE,
+                           cwd=path_to_src)
+  (out, _) = proc.communicate()
+
+  for line in out.splitlines():
+    (k, _, v) = line.partition('=')
+    os.environ[k] = v
+  # envsetup.sh no longer sets OS=android to GYP_DEFINES env variable
+  # (CL/170273005). Set this variable explicitly inorder to build chrome on
+  # android.
+  try:
+    if 'OS=android' not in os.environ['GYP_DEFINES']:
+      os.environ['GYP_DEFINES'] = '%s %s' % (os.environ['GYP_DEFINES'],
+                                              'OS=android')
+  except KeyError:
+    os.environ['GYP_DEFINES'] = 'OS=android'
+
+  if opts.use_goma:
+    os.environ['GYP_DEFINES'] = '%s %s' % (os.environ['GYP_DEFINES'],
+                                           'use_goma=1')
+  return not proc.returncode
+
+
+def SetupPlatformBuildEnvironment(opts):
+  """Performs any platform specific setup.
+
+  Args:
+    opts: The options parsed from the command line through parse_args().
+
+  Returns:
+    True if successful.
+  """
+  if 'android' in opts.target_platform:
+    CopyAndSaveOriginalEnvironmentVars()
+    return SetupAndroidBuildEnvironment(opts)
+  elif opts.target_platform == 'cros':
+    return SetupCrosRepo()
+
+  return True
+
+
+def CheckIfBisectDepotExists(opts):
+  """Checks if the bisect directory already exists.
+
+  Args:
+    opts: The options parsed from the command line through parse_args().
+
+  Returns:
+    Returns True if it exists.
+  """
+  path_to_dir = os.path.join(opts.working_directory, 'bisect', 'src')
+  return os.path.exists(path_to_dir)
+
+
+def CreateBisectDirectoryAndSetupDepot(opts, custom_deps):
+  """Sets up a subdirectory 'bisect' and then retrieves a copy of the depot
+  there using gclient.
+
+  Args:
+    opts: The options parsed from the command line through parse_args().
+    custom_deps: A dictionary of additional dependencies to add to .gclient.
+  """
+  if not CreateAndChangeToSourceDirectory(opts.working_directory):
+    raise RuntimeError('Could not create bisect directory.')
+
+  if not SetupGitDepot(opts, custom_deps):
+    raise RuntimeError('Failed to grab source.')
diff --git a/tools/auto_bisect/post_perf_builder_job.py b/tools/auto_bisect/post_perf_builder_job.py
new file mode 100644
index 0000000..97c6ecc
--- /dev/null
+++ b/tools/auto_bisect/post_perf_builder_job.py
@@ -0,0 +1,372 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Post a try job request via HTTP to the Tryserver to produce build."""
+
+import getpass
+import json
+import optparse
+import os
+import sys
+import urllib
+import urllib2
+
+# Link to get JSON data of builds
+BUILDER_JSON_URL = ('%(server_url)s/json/builders/%(bot_name)s/builds/'
+                    '%(build_num)s?as_text=1&filter=0')
+
+# Link to display build steps
+BUILDER_HTML_URL = ('%(server_url)s/builders/%(bot_name)s/builds/%(build_num)s')
+
+# Tryserver buildbots status page
+TRY_SERVER_URL = 'http://build.chromium.org/p/tryserver.chromium.perf'
+
+# Hostname of the tryserver where perf bisect builders are hosted. This is used
+# for posting build request to tryserver.
+BISECT_BUILDER_HOST = 'master4.golo.chromium.org'
+# 'try_job_port' on tryserver to post build request.
+BISECT_BUILDER_PORT = 8341
+
+
+# From buildbot.status.builder.
+# See: http://docs.buildbot.net/current/developer/results.html
+SUCCESS, WARNINGS, FAILURE, SKIPPED, EXCEPTION, RETRY, TRYPENDING = range(7)
+
+# Status codes that can be returned by the GetBuildStatus method.
+OK = (SUCCESS, WARNINGS)
+# Indicates build failure.
+FAILED = (FAILURE, EXCEPTION, SKIPPED)
+# Inidcates build in progress or in pending queue.
+PENDING = (RETRY, TRYPENDING)
+
+
+class ServerAccessError(Exception):
+
+  def __str__(self):
+    return '%s\nSorry, cannot connect to server.' % self.args[0]
+
+
+def PostTryJob(url_params):
+  """Sends a build request to the server using the HTTP protocol.
+
+  Args:
+    url_params: A dictionary of query parameters to be sent in the request.
+                In order to post build request to try server, this dictionary
+                should contain information for following keys:
+                'host': Hostname of the try server.
+                'port': Port of the try server.
+                'revision': SVN Revision to build.
+                'bot': Name of builder bot which would be used.
+  Returns:
+    True if the request is posted successfully. Otherwise throws an exception.
+  """
+  # Parse url parameters to be sent to Try server.
+  if not url_params.get('host'):
+    raise ValueError('Hostname of server to connect is missing.')
+  if not url_params.get('port'):
+    raise ValueError('Port of server to connect is missing.')
+  if not url_params.get('revision'):
+    raise ValueError('Missing revision details. Please specify revision'
+                     ' information.')
+  if not url_params.get('bot'):
+    raise ValueError('Missing bot details. Please specify bot information.')
+
+  # Pop 'host' and 'port' to avoid passing them as query params.
+  url = 'http://%s:%s/send_try_patch' % (url_params.pop('host'),
+                                         url_params.pop('port'))
+
+  print 'Sending by HTTP'
+  query_params = '&'.join('%s=%s' % (k, v) for k, v in url_params.iteritems())
+  print 'url: %s?%s' % (url, query_params)
+
+  connection = None
+  try:
+    print 'Opening connection...'
+    connection = urllib2.urlopen(url, urllib.urlencode(url_params))
+    print 'Done, request sent to server to produce build.'
+  except IOError, e:
+    raise ServerAccessError('%s is unaccessible. Reason: %s' % (url, e))
+  if not connection:
+    raise ServerAccessError('%s is unaccessible.' % url)
+  response = connection.read()
+  print 'Received %s from server' % response
+  if response != 'OK':
+    raise ServerAccessError('%s is unaccessible. Got:\n%s' % (url, response))
+  return True
+
+
+def _IsBuildRunning(build_data):
+  """Checks whether the build is in progress on buildbot.
+
+  Presence of currentStep element in build JSON indicates build is in progress.
+
+  Args:
+    build_data: A dictionary with build data, loaded from buildbot JSON API.
+
+  Returns:
+    True if build is in progress, otherwise False.
+  """
+  current_step = build_data.get('currentStep')
+  if (current_step and current_step.get('isStarted') and
+      current_step.get('results') is None):
+    return True
+  return False
+
+
+def _IsBuildFailed(build_data):
+  """Checks whether the build failed on buildbot.
+
+  Sometime build status is marked as failed even though compile and packaging
+  steps are successful. This may happen due to some intermediate steps of less
+  importance such as gclient revert, generate_telemetry_profile are failed.
+  Therefore we do an addition check to confirm if build was successful by
+  calling _IsBuildSuccessful.
+
+  Args:
+    build_data: A dictionary with build data, loaded from buildbot JSON API.
+
+  Returns:
+    True if revision is failed build, otherwise False.
+  """
+  if (build_data.get('results') in FAILED and
+      not _IsBuildSuccessful(build_data)):
+    return True
+  return False
+
+
+def _IsBuildSuccessful(build_data):
+  """Checks whether the build succeeded on buildbot.
+
+  We treat build as successful if the package_build step is completed without
+  any error i.e., when results attribute of the this step has value 0 or 1
+  in its first element.
+
+  Args:
+    build_data: A dictionary with build data, loaded from buildbot JSON API.
+
+  Returns:
+    True if revision is successfully build, otherwise False.
+  """
+  if build_data.get('steps'):
+    for item in build_data.get('steps'):
+      # The 'results' attribute of each step consists of two elements,
+      # results[0]: This represents the status of build step.
+      # See: http://docs.buildbot.net/current/developer/results.html
+      # results[1]: List of items, contains text if step fails, otherwise empty.
+      if (item.get('name') == 'package_build' and
+          item.get('isFinished') and
+          item.get('results')[0] in OK):
+        return True
+  return False
+
+
+def _FetchBuilderData(builder_url):
+  """Fetches JSON data for the all the builds from the tryserver.
+
+  Args:
+    builder_url: A tryserver URL to fetch builds information.
+
+  Returns:
+    A dictionary with information of all build on the tryserver.
+  """
+  data = None
+  try:
+    url = urllib2.urlopen(builder_url)
+  except urllib2.URLError, e:
+    print ('urllib2.urlopen error %s, waterfall status page down.[%s]' % (
+        builder_url, str(e)))
+    return None
+  if url is not None:
+    try:
+      data = url.read()
+    except IOError, e:
+      print 'urllib2 file object read error %s, [%s].' % (builder_url, str(e))
+  return data
+
+
+def _GetBuildData(buildbot_url):
+  """Gets build information for the given build id from the tryserver.
+
+  Args:
+    buildbot_url: A tryserver URL to fetch build information.
+
+  Returns:
+    A dictionary with build information if build exists, otherwise None.
+  """
+  builds_json = _FetchBuilderData(buildbot_url)
+  if builds_json:
+    return json.loads(builds_json)
+  return None
+
+
+def _GetBuildBotUrl(builder_host, builder_port):
+  """Gets build bot URL based on the host and port of the builders.
+
+  Note: All bisect builder bots are hosted on tryserver.chromium i.e.,
+  on master4:8328, since we cannot access tryserver using host and port
+  number directly, we use tryserver URL.
+
+  Args:
+    builder_host: Hostname of the server where the builder is hosted.
+    builder_port: Port number of ther server where the builder is hosted.
+
+  Returns:
+    URL of the buildbot as a string.
+  """
+  if (builder_host == BISECT_BUILDER_HOST and
+      builder_port == BISECT_BUILDER_PORT):
+    return TRY_SERVER_URL
+  else:
+    return 'http://%s:%s' % (builder_host, builder_port)
+
+
+def GetBuildStatus(build_num, bot_name, builder_host, builder_port):
+  """Gets build status from the buildbot status page for a given build number.
+
+  Args:
+    build_num: A build number on tryserver to determine its status.
+    bot_name: Name of the bot where the build information is scanned.
+    builder_host: Hostname of the server where the builder is hosted.
+    builder_port: Port number of ther server where the builder is hosted.
+
+  Returns:
+    A tuple consists of build status (SUCCESS, FAILED or PENDING) and a link
+    to build status page on the waterfall.
+  """
+  results_url = None
+  if build_num:
+    # Gets the buildbot url for the given host and port.
+    server_url = _GetBuildBotUrl(builder_host, builder_port)
+    buildbot_url = BUILDER_JSON_URL % {'server_url': server_url,
+                                       'bot_name': bot_name,
+                                       'build_num': build_num
+                                      }
+    build_data = _GetBuildData(buildbot_url)
+    if build_data:
+      # Link to build on the buildbot showing status of build steps.
+      results_url = BUILDER_HTML_URL % {'server_url': server_url,
+                                        'bot_name': bot_name,
+                                        'build_num': build_num
+                                       }
+      if _IsBuildFailed(build_data):
+        return (FAILED, results_url)
+
+      elif _IsBuildSuccessful(build_data):
+        return (OK, results_url)
+  return (PENDING, results_url)
+
+
+def GetBuildNumFromBuilder(build_reason, bot_name, builder_host, builder_port):
+  """Gets build number on build status page for a given build reason.
+
+  It parses the JSON data from buildbot page and collect basic information
+  about the all the builds and then this uniquely identifies the build based
+  on the 'reason' attribute in builds's JSON data.
+  The 'reason' attribute set while a build request is posted, and same is used
+  to identify the build on status page.
+
+  Args:
+    build_reason: A unique build name set to build on tryserver.
+    bot_name: Name of the bot where the build information is scanned.
+    builder_host: Hostname of the server where the builder is hosted.
+    builder_port: Port number of ther server where the builder is hosted.
+
+  Returns:
+    A build number as a string if found, otherwise None.
+  """
+  # Gets the buildbot url for the given host and port.
+  server_url = _GetBuildBotUrl(builder_host, builder_port)
+  buildbot_url = BUILDER_JSON_URL % {'server_url': server_url,
+                                     'bot_name': bot_name,
+                                     'build_num': '_all'
+                                    }
+  builds_json = _FetchBuilderData(buildbot_url)
+  if builds_json:
+    builds_data = json.loads(builds_json)
+    for current_build in builds_data:
+      if builds_data[current_build].get('reason') == build_reason:
+        return builds_data[current_build].get('number')
+  return None
+
+
+def _GetQueryParams(options):
+  """Parses common query parameters which will be passed to PostTryJob.
+
+  Args:
+    options: The options object parsed from the command line.
+
+  Returns:
+    A dictionary consists of query parameters.
+  """
+  values = {'host': options.host,
+            'port': options.port,
+            'user': options.user,
+            'name': options.name
+           }
+  if options.email:
+    values['email'] = options.email
+  if options.revision:
+    values['revision'] = options.revision
+  if options.root:
+    values['root'] = options.root
+  if options.bot:
+    values['bot'] = options.bot
+  if options.patch:
+    values['patch'] = options.patch
+  return values
+
+
+def _GenParser():
+  """Parses the command line for posting build request."""
+  usage = ('%prog [options]\n'
+           'Post a build request to the try server for the given revision.\n')
+  parser = optparse.OptionParser(usage=usage)
+  parser.add_option('-H', '--host',
+                    help='Host address of the try server.')
+  parser.add_option('-P', '--port', type='int',
+                    help='HTTP port of the try server.')
+  parser.add_option('-u', '--user', default=getpass.getuser(),
+                    dest='user',
+                    help='Owner user name [default: %default]')
+  parser.add_option('-e', '--email',
+                    default=os.environ.get('TRYBOT_RESULTS_EMAIL_ADDRESS',
+                                           os.environ.get('EMAIL_ADDRESS')),
+                    help=('Email address where to send the results. Use either '
+                          'the TRYBOT_RESULTS_EMAIL_ADDRESS environment '
+                          'variable or EMAIL_ADDRESS to set the email address '
+                          'the try bots report results to [default: %default]'))
+  parser.add_option('-n', '--name',
+                    default='try_job_http',
+                    help='Descriptive name of the try job')
+  parser.add_option('-b', '--bot',
+                    help=('IMPORTANT: specify ONE builder per run is supported.'
+                          'Run script for each builders separately.'))
+  parser.add_option('-r', '--revision',
+                    help=('Revision to use for the try job; default: the '
+                          'revision will be determined by the try server; see '
+                          'its waterfall for more info'))
+  parser.add_option('--root',
+                    help=('Root to use for the patch; base subdirectory for '
+                          'patch created in a subdirectory'))
+  parser.add_option('--patch',
+                    help='Patch information.')
+  return parser
+
+
+def Main(argv):
+  parser = _GenParser()
+  options, _ = parser.parse_args()
+  if not options.host:
+    raise ServerAccessError('Please use the --host option to specify the try '
+                            'server host to connect to.')
+  if not options.port:
+    raise ServerAccessError('Please use the --port option to specify the try '
+                            'server port to connect to.')
+  params = _GetQueryParams(options)
+  PostTryJob(params)
+
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv))
+