testing/xvfb.py

   1 #!/usr/bin/env python
   2 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5
   6 """Runs tests with Xvfb and Openbox on Linux and normally on other platforms."""
   7
   8 import os
   9 import platform
  10 import signal
  11 import subprocess
  12 import sys
  13 import threading
  14
  15 import test_env
  16
  17
  18 def _kill(proc, send_signal):
  19   """Kills |proc| and ignores exceptions thrown for non-existent processes."""
  20   try:
  21     os.kill(proc.pid, send_signal)
  22   except OSError:
  23     pass
  24
  25
  26 def kill(proc, timeout_in_seconds=10):
  27   """Tries to kill |proc| gracefully with a timeout for each signal."""
  28   if not proc or not proc.pid:
  29     return
  30
  31   _kill(proc, signal.SIGTERM)
  32   thread = threading.Thread(target=proc.wait)
  33   thread.start()
  34
  35   thread.join(timeout_in_seconds)
  36   if thread.is_alive():
  37     print >> sys.stderr, 'Xvfb running after SIGTERM, trying SIGKILL.'
  38     _kill(proc, signal.SIGKILL)
  39
  40   thread.join(timeout_in_seconds)
  41   if thread.is_alive():
  42     print >> sys.stderr, 'Xvfb running after SIGTERM and SIGKILL; good luck!'
  43
  44
  45 def wait_for_xvfb(xdisplaycheck, env):
  46   """Waits for xvfb to be fully initialized by using xdisplaycheck."""
  47   try:
  48     subprocess.check_output([xdisplaycheck], stderr=subprocess.STDOUT, env=env)
  49   except OSError:
  50     print >> sys.stderr, 'Failed to load %s with cwd=%s' % (
  51         xdisplaycheck, os.getcwd())
  52     return False
  53   except subprocess.CalledProcessError as e:
  54     print >> sys.stderr, ('Xvfb failed to load (code %d) according to %s' %
  55                           (e.returncode, xdisplaycheck))
  56     return False
  57
  58   return True
  59
  60
  61 def should_start_xvfb(env):
  62   """Xvfb is only used on Linux and shouldn't be invoked recursively."""
  63   return sys.platform == 'linux2' and env.get('_CHROMIUM_INSIDE_XVFB') != '1'
  64
  65
  66 def start_xvfb(env, build_dir, xvfb_path='Xvfb', display=':9'):
  67   """Start a virtual X server that can run tests without an existing X session.
  68
  69   Returns the Xvfb and Openbox process Popen objects, or None on failure.
  70   The |env| dictionary is modified to set the DISPLAY and prevent re-entry.
  71
  72   Args:
  73     env:       The os.environ dictionary [copy] to check for re-entry.
  74     build_dir: The path of the build directory, used for xdisplaycheck.
  75     xvfb_path: The path to Xvfb.
  76     display:   The X display number to use.
  77   """
  78   assert should_start_xvfb(env)
  79   assert env.get('_CHROMIUM_INSIDE_XVFB') != '1'
  80   env['_CHROMIUM_INSIDE_XVFB'] = '1'
  81   env['DISPLAY'] = display
  82   xvfb_proc = None
  83   openbox_proc = None
  84
  85   try:
  86     xvfb_cmd = [xvfb_path, display, '-screen', '0', '1024x768x24', '-ac',
  87                 '-nolisten', 'tcp', '-dpi', '96']
  88     xvfb_proc = subprocess.Popen(xvfb_cmd, stdout=subprocess.PIPE,
  89                                  stderr=subprocess.STDOUT)
  90
  91     if not wait_for_xvfb(os.path.join(build_dir, 'xdisplaycheck'), env):
  92       rc = xvfb_proc.poll()
  93       if rc is None:
  94         print 'Xvfb still running after xdisplaycheck failure, stopping.'
  95         kill(xvfb_proc)
  96       else:
  97         print 'Xvfb exited (code %d) after xdisplaycheck failure.' % rc
  98       print 'Xvfb output:'
  99       for l in xvfb_proc.communicate()[0].splitlines():
 100         print '> %s' % l
 101       return (None, None)
 102
 103     # Some ChromeOS tests need a window manager.
 104     openbox_proc = subprocess.Popen('openbox', stdout=subprocess.PIPE,
 105                                     stderr=subprocess.STDOUT, env=env)
 106   except OSError as e:
 107     print >> sys.stderr, 'Failed to start Xvfb or Openbox: %s' % str(e)
 108     kill(xvfb_proc)
 109     kill(openbox_proc)
 110     return (None, None)
 111
 112   return (xvfb_proc, openbox_proc)
 113
 114
 115 def run_executable(cmd, build_dir, env):
 116   """Runs an executable within Xvfb on Linux or normally on other platforms.
 117
 118   Returns the exit code of the specified commandline, or 1 on failure.
 119   """
 120   xvfb = None
 121   openbox = None
 122   if should_start_xvfb(env):
 123     (xvfb, openbox) = start_xvfb(env, build_dir)
 124     if not xvfb or not xvfb.pid or not openbox or not openbox.pid:
 125       return 1
 126   try:
 127     return test_env.run_executable(cmd, env)
 128   finally:
 129     kill(xvfb)
 130     kill(openbox)
 131
 132
 133 def main():
 134   if len(sys.argv) < 3:
 135     print >> sys.stderr, (
 136         'Usage: xvfb.py [path to build_dir] [command args...]')
 137     return 2
 138   return run_executable(sys.argv[2:], sys.argv[1], os.environ.copy())
 139
 140
 141 if __name__ == "__main__":
 142   sys.exit(main())