xvfb Namespace Reference

Functions
	xvfb_display_index (_child_build_name)
	xvfb_pid_filename (child_build_name)
	start_virtual_x (child_build_name, build_dir)
	stop_virtual_x (child_build_name)

Detailed Description

Functions to setup xvfb, which is used by the linux machines.

Function Documentation

start_virtual_x()

xvfb.start_virtual_x	(		child_build_name,
			build_dir
	)

Start a virtual X server and set the DISPLAY environment variable so sub
processes will use the virtual X server.  Also start openbox. This only works
on Linux and assumes that xvfb and openbox are installed.

Args:
  child_build_name: The name of the build that we use for the pid file.
      E.g., webkit-rel-linux.
  build_dir: The directory where binaries are produced.  If this is non-empty,
      we try running xdisplaycheck from |build_dir| to verify our X
      connection.

Definition at line 27 of file xvfb.py.

def start_virtual_x(child_build_name, build_dir):
  """Start a virtual X server and set the DISPLAY environment variable so sub
  processes will use the virtual X server.  Also start openbox. This only works
  on Linux and assumes that xvfb and openbox are installed.
 
  Args:
    child_build_name: The name of the build that we use for the pid file.
        E.g., webkit-rel-linux.
    build_dir: The directory where binaries are produced.  If this is non-empty,
        we try running xdisplaycheck from |build_dir| to verify our X
        connection.
  """
  # We use a pid file to make sure we don't have any xvfb processes running
  # from a previous test run.
  stop_virtual_x(child_build_name)
 
  xdisplaycheck_path = None
  if build_dir:
    xdisplaycheck_path = os.path.join(build_dir, 'xdisplaycheck')
 
  display = ':%s' % xvfb_display_index(child_build_name)
  # Note we don't add the optional screen here (+ '.0')
  os.environ['DISPLAY'] = display
 
  # Parts of Xvfb use a hard-coded "/tmp" for its temporary directory.
  # This can cause a failure when those parts expect to hardlink against
  # files that were created in "TEMPDIR" / "TMPDIR".
  #
  # See: https://crbug.com/715848
  env = os.environ.copy()
  if env.get('TMPDIR') and env['TMPDIR'] != '/tmp':
    print('Overriding TMPDIR to "/tmp" for Xvfb, was: %s' % (env['TMPDIR'],))
    env['TMPDIR'] = '/tmp'
 
  if xdisplaycheck_path and os.path.exists(xdisplaycheck_path):
    print('Verifying Xvfb is not running ...')
    checkstarttime = time.time()
    xdisplayproc = subprocess.Popen([xdisplaycheck_path, '--noserver'],
                                    stdout=subprocess.PIPE,
                                    stderr=subprocess.STDOUT,
                                    env=env)
    # Wait for xdisplaycheck to exit.
    logs = xdisplayproc.communicate()[0]
    if xdisplayproc.returncode == 0:
      print('xdisplaycheck says there is a display still running, exiting...')
      raise Exception('Display already present.')
 
    xvfb_lock_filename = '/tmp/.X%s-lock' % xvfb_display_index(child_build_name)
    if os.path.exists(xvfb_lock_filename):
      print('Removing stale xvfb lock file %r' % xvfb_lock_filename)
      try:
        os.unlink(xvfb_lock_filename)
      except OSError as err:
        print('Removing xvfb lock file failed: %s' % err)
 
  # Figure out which X server to try.
  cmd = 'Xvfb'
 
  # Start a virtual X server that we run the tests in.  This makes it so we can
  # run the tests even if we didn't start the tests from an X session.
  proc = subprocess.Popen([
      cmd, display, '-screen', '0', '1280x800x24', '-ac', '-dpi', '96', '-maxclients', '512',
      '-extension', 'MIT-SHM'
  ],
                          stdout=subprocess.PIPE,
                          stderr=subprocess.STDOUT,
                          env=env)
  pid_filename = xvfb_pid_filename(child_build_name)
  open(pid_filename, 'w').write(str(proc.pid))
 
  # Wait for Xvfb to start up.
  time.sleep(10)
 
  # Verify that Xvfb has started by using xdisplaycheck.
  if xdisplaycheck_path and os.path.exists(xdisplaycheck_path):
    print('Verifying Xvfb has started...')
    checkstarttime = time.time()
    xdisplayproc = subprocess.Popen([xdisplaycheck_path],
                                    stdout=subprocess.PIPE,
                                    stderr=subprocess.STDOUT)
    # Wait for xdisplaycheck to exit.
    logs = xdisplayproc.communicate()[0]
    checktime = time.time() - checkstarttime
    if xdisplayproc.returncode != 0:
      print('xdisplaycheck failed after %d seconds.' % checktime)
      print('xdisplaycheck output:')
      for line in logs.splitlines():
        print('> %s' % line)
      return_code = proc.poll()
      if return_code is None:
        print('Xvfb still running, stopping.')
        proc.terminate()
      else:
        print('Xvfb exited, code %d' % return_code)
 
      print('Xvfb output:')
      for line in proc.communicate()[0].splitlines():
        print('> %s' % line)
      raise Exception(logs)
 
    print('xdisplaycheck succeeded after %d seconds.' % checktime)
    print('xdisplaycheck output:')
    for line in logs.splitlines():
      print('> %s' % line)
    print('...OK')
 
  # Some ChromeOS tests need a window manager.
  subprocess.Popen('openbox', stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
  print('Window manager (openbox) started.')
 
 

stop_virtual_x()

xvfb.stop_virtual_x

(

child_build_name

)

Try and stop the virtual X server if one was started with StartVirtualX.
When the X server dies, it takes down the window manager with it.
If a virtual x server is not running, this method does nothing.

Definition at line 138 of file xvfb.py.

def stop_virtual_x(child_build_name):
  """Try and stop the virtual X server if one was started with StartVirtualX.
  When the X server dies, it takes down the window manager with it.
  If a virtual x server is not running, this method does nothing."""
  pid_filename = xvfb_pid_filename(child_build_name)
  if os.path.exists(pid_filename):
    xvfb_pid = int(open(pid_filename).read())
    print('Stopping Xvfb with pid %d ...' % xvfb_pid)
    # If the process doesn't exist, we raise an exception that we can ignore.
    try:
      os.kill(xvfb_pid, signal.SIGKILL)
    except OSError:
      print('... killing failed, presuming unnecessary.')
    os.remove(pid_filename)
    print('Xvfb pid file removed')

xvfb_display_index()

xvfb.xvfb_display_index

(

_child_build_name

)

Definition at line 15 of file xvfb.py.

def xvfb_display_index(_child_build_name):
  return '9'
 
 

xvfb_pid_filename()

xvfb.xvfb_pid_filename

(

child_build_name

)

Returns the filename to the Xvfb pid file.  This name is unique for each
builder. This is used by the linux builders.

Definition at line 19 of file xvfb.py.

def xvfb_pid_filename(child_build_name):
  """Returns the filename to the Xvfb pid file.  This name is unique for each
  builder. This is used by the linux builders."""
  return os.path.join(
      tempfile.gettempdir(), 'xvfb-' + xvfb_display_index(child_build_name) + '.pid'
  )