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build/android/pylib/chrome_test_server_spawner.py

Index: build/android/pylib/chrome_test_server_spawner.py
diff --git a/build/android/pylib/chrome_test_server_spawner.py b/build/android/pylib/chrome_test_server_spawner.py
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+# Copyright 2013 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.
+
+"""A "Test Server Spawner" that handles killing/stopping per-test test servers.
+
+It's used to accept requests from the device to spawn and kill instances of the
+chrome test server on the host.
+"""
+# pylint: disable=W0702
+
+import BaseHTTPServer
+import json
+import logging
+import os
+import select
+import struct
+import subprocess
+import sys
+import threading
+import time
+import urlparse
+
+from pylib import constants
+from pylib import ports
+
+from pylib.forwarder import Forwarder
+
+
+# Path that are needed to import necessary modules when launching a testserver.
+os.environ['PYTHONPATH'] = os.environ.get('PYTHONPATH', '') + (':%s:%s:%s:%s:%s'
+    % (os.path.join(constants.DIR_SOURCE_ROOT, 'third_party'),
+       os.path.join(constants.DIR_SOURCE_ROOT, 'third_party', 'tlslite'),
+       os.path.join(constants.DIR_SOURCE_ROOT, 'third_party', 'pyftpdlib',
+                    'src'),
+       os.path.join(constants.DIR_SOURCE_ROOT, 'net', 'tools', 'testserver'),
+       os.path.join(constants.DIR_SOURCE_ROOT, 'sync', 'tools', 'testserver')))
+
+
+SERVER_TYPES = {
+    'http': '',
+    'ftp': '-f',
+    'sync': '',  # Sync uses its own script, and doesn't take a server type arg.
+    'tcpecho': '--tcp-echo',
+    'udpecho': '--udp-echo',
+}
+
+
+# The timeout (in seconds) of starting up the Python test server.
+TEST_SERVER_STARTUP_TIMEOUT = 10
+
+def _WaitUntil(predicate, max_attempts=5):
+  """Blocks until the provided predicate (function) is true.
+
+  Returns:
+    Whether the provided predicate was satisfied once (before the timeout).
+  """
+  sleep_time_sec = 0.025
+  for _ in xrange(1, max_attempts):
+    if predicate():
+      return True
+    time.sleep(sleep_time_sec)
+    sleep_time_sec = min(1, sleep_time_sec * 2)  # Don't wait more than 1 sec.
+  return False
+
+
+def _CheckPortAvailable(port):
+  """Returns True if |port| is available."""
+  return _WaitUntil(lambda: ports.IsHostPortAvailable(port))
+
+
+def _CheckPortNotAvailable(port):
+  """Returns True if |port| is not available."""
+  return _WaitUntil(lambda: not ports.IsHostPortAvailable(port))
+
+
+def _CheckDevicePortStatus(device, port):
+  """Returns whether the provided port is used."""
+  return _WaitUntil(lambda: ports.IsDevicePortUsed(device, port))
+
+
+def _GetServerTypeCommandLine(server_type):
+  """Returns the command-line by the given server type.
+
+  Args:
+    server_type: the server type to be used (e.g. 'http').
+
+  Returns:
+    A string containing the command-line argument.
+  """
+  if server_type not in SERVER_TYPES:
+    raise NotImplementedError('Unknown server type: %s' % server_type)
+  if server_type == 'udpecho':
+    raise Exception('Please do not run UDP echo tests because we do not have '
+                    'a UDP forwarder tool.')
+  return SERVER_TYPES[server_type]
+
+
+class TestServerThread(threading.Thread):
+  """A thread to run the test server in a separate process."""
+
+  def __init__(self, ready_event, arguments, device, tool):
+    """Initialize TestServerThread with the following argument.
+
+    Args:
+      ready_event: event which will be set when the test server is ready.
+      arguments: dictionary of arguments to run the test server.
+      device: An instance of DeviceUtils.
+      tool: instance of runtime error detection tool.
+    """
+    threading.Thread.__init__(self)
+    self.wait_event = threading.Event()
+    self.stop_flag = False
+    self.ready_event = ready_event
+    self.ready_event.clear()
+    self.arguments = arguments
+    self.device = device
+    self.tool = tool
+    self.test_server_process = None
+    self.is_ready = False
+    self.host_port = self.arguments['port']
+    assert isinstance(self.host_port, int)
+    # The forwarder device port now is dynamically allocated.
+    self.forwarder_device_port = 0
+    # Anonymous pipe in order to get port info from test server.
+    self.pipe_in = None
+    self.pipe_out = None
+    self.process = None
+    self.command_line = []
+
+  def _WaitToStartAndGetPortFromTestServer(self):
+    """Waits for the Python test server to start and gets the port it is using.
+
+    The port information is passed by the Python test server with a pipe given
+    by self.pipe_out. It is written as a result to |self.host_port|.
+
+    Returns:
+      Whether the port used by the test server was successfully fetched.
+    """
+    assert self.host_port == 0 and self.pipe_out and self.pipe_in
+    (in_fds, _, _) = select.select([self.pipe_in, ], [], [],
+                                   TEST_SERVER_STARTUP_TIMEOUT)
+    if len(in_fds) == 0:
+      logging.error('Failed to wait to the Python test server to be started.')
+      return False
+    # First read the data length as an unsigned 4-byte value.  This
+    # is _not_ using network byte ordering since the Python test server packs
+    # size as native byte order and all Chromium platforms so far are
+    # configured to use little-endian.
+    # TODO(jnd): Change the Python test server and local_test_server_*.cc to
+    # use a unified byte order (either big-endian or little-endian).
+    data_length = os.read(self.pipe_in, struct.calcsize('=L'))
+    if data_length:
+      (data_length,) = struct.unpack('=L', data_length)
+      assert data_length
+    if not data_length:
+      logging.error('Failed to get length of server data.')
+      return False
+    port_json = os.read(self.pipe_in, data_length)
+    if not port_json:
+      logging.error('Failed to get server data.')
+      return False
+    logging.info('Got port json data: %s', port_json)
+    port_json = json.loads(port_json)
+    if port_json.has_key('port') and isinstance(port_json['port'], int):
+      self.host_port = port_json['port']
+      return _CheckPortNotAvailable(self.host_port)
+    logging.error('Failed to get port information from the server data.')
+    return False
+
+  def _GenerateCommandLineArguments(self):
+    """Generates the command line to run the test server.
+
+    Note that all options are processed by following the definitions in
+    testserver.py.
+    """
+    if self.command_line:
+      return
+
+    args_copy = dict(self.arguments)
+
+    # Translate the server type.
+    type_cmd = _GetServerTypeCommandLine(args_copy.pop('server-type'))
+    if type_cmd:
+      self.command_line.append(type_cmd)
+
+    # Use a pipe to get the port given by the instance of Python test server
+    # if the test does not specify the port.
+    assert self.host_port == args_copy['port']
+    if self.host_port == 0:
+      (self.pipe_in, self.pipe_out) = os.pipe()
+      self.command_line.append('--startup-pipe=%d' % self.pipe_out)
+
+    # Pass the remaining arguments as-is.
+    for key, values in args_copy.iteritems():
+      if not isinstance(values, list):
+        values = [values]
+      for value in values:
+        if value is None:
+          self.command_line.append('--%s' % key)
+        else:
+          self.command_line.append('--%s=%s' % (key, value))
+
+  def _CloseUnnecessaryFDsForTestServerProcess(self):
+    # This is required to avoid subtle deadlocks that could be caused by the
+    # test server child process inheriting undesirable file descriptors such as
+    # file lock file descriptors.
+    for fd in xrange(0, 1024):
+      if fd != self.pipe_out:
+        try:
+          os.close(fd)
+        except:
+          pass
+
+  def run(self):
+    logging.info('Start running the thread!')
+    self.wait_event.clear()
+    self._GenerateCommandLineArguments()
+    command = constants.DIR_SOURCE_ROOT
+    if self.arguments['server-type'] == 'sync':
+      command = [os.path.join(command, 'sync', 'tools', 'testserver',
+                              'sync_testserver.py')] + self.command_line
+    else:
+      command = [os.path.join(command, 'net', 'tools', 'testserver',
+                              'testserver.py')] + self.command_line
+    logging.info('Running: %s', command)
+    # Pass DIR_SOURCE_ROOT as the child's working directory so that relative
+    # paths in the arguments are resolved correctly.
+    self.process = subprocess.Popen(
+        command, preexec_fn=self._CloseUnnecessaryFDsForTestServerProcess,
+        cwd=constants.DIR_SOURCE_ROOT)
+    if self.process:
+      if self.pipe_out:
+        self.is_ready = self._WaitToStartAndGetPortFromTestServer()
+      else:
+        self.is_ready = _CheckPortNotAvailable(self.host_port)
+    if self.is_ready:
+      Forwarder.Map([(0, self.host_port)], self.device, self.tool)
+      # Check whether the forwarder is ready on the device.
+      self.is_ready = False
+      device_port = Forwarder.DevicePortForHostPort(self.host_port)
+      if device_port and _CheckDevicePortStatus(self.device, device_port):
+        self.is_ready = True
+        self.forwarder_device_port = device_port
+    # Wake up the request handler thread.
+    self.ready_event.set()
+    # Keep thread running until Stop() gets called.
+    _WaitUntil(lambda: self.stop_flag, max_attempts=sys.maxint)
+    if self.process.poll() is None:
+      self.process.kill()
+    Forwarder.UnmapDevicePort(self.forwarder_device_port, self.device)
+    self.process = None
+    self.is_ready = False
+    if self.pipe_out:
+      os.close(self.pipe_in)
+      os.close(self.pipe_out)
+      self.pipe_in = None
+      self.pipe_out = None
+    logging.info('Test-server has died.')
+    self.wait_event.set()
+
+  def Stop(self):
+    """Blocks until the loop has finished.
+
+    Note that this must be called in another thread.
+    """
+    if not self.process:
+      return
+    self.stop_flag = True
+    self.wait_event.wait()
+
+
+class SpawningServerRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
+  """A handler used to process http GET/POST request."""
+
+  def _SendResponse(self, response_code, response_reason, additional_headers,
+                    contents):
+    """Generates a response sent to the client from the provided parameters.
+
+    Args:
+      response_code: number of the response status.
+      response_reason: string of reason description of the response.
+      additional_headers: dict of additional headers. Each key is the name of
+                          the header, each value is the content of the header.
+      contents: string of the contents we want to send to client.
+    """
+    self.send_response(response_code, response_reason)
+    self.send_header('Content-Type', 'text/html')
+    # Specify the content-length as without it the http(s) response will not
+    # be completed properly (and the browser keeps expecting data).
+    self.send_header('Content-Length', len(contents))
+    for header_name in additional_headers:
+      self.send_header(header_name, additional_headers[header_name])
+    self.end_headers()
+    self.wfile.write(contents)
+    self.wfile.flush()
+
+  def _StartTestServer(self):
+    """Starts the test server thread."""
+    logging.info('Handling request to spawn a test server.')
+    content_type = self.headers.getheader('content-type')
+    if content_type != 'application/json':
+      raise Exception('Bad content-type for start request.')
+    content_length = self.headers.getheader('content-length')
+    if not content_length:
+      content_length = 0
+    try:
+      content_length = int(content_length)
+    except:
+      raise Exception('Bad content-length for start request.')
+    logging.info(content_length)
+    test_server_argument_json = self.rfile.read(content_length)
+    logging.info(test_server_argument_json)
+    assert not self.server.test_server_instance
+    ready_event = threading.Event()
+    self.server.test_server_instance = TestServerThread(
+        ready_event,
+        json.loads(test_server_argument_json),
+        self.server.device,
+        self.server.tool)
+    self.server.test_server_instance.setDaemon(True)
+    self.server.test_server_instance.start()
+    ready_event.wait()
+    if self.server.test_server_instance.is_ready:
+      self._SendResponse(200, 'OK', {}, json.dumps(
+          {'port': self.server.test_server_instance.forwarder_device_port,
+           'message': 'started'}))
+      logging.info('Test server is running on port: %d.',
+                   self.server.test_server_instance.host_port)
+    else:
+      self.server.test_server_instance.Stop()
+      self.server.test_server_instance = None
+      self._SendResponse(500, 'Test Server Error.', {}, '')
+      logging.info('Encounter problem during starting a test server.')
+
+  def _KillTestServer(self):
+    """Stops the test server instance."""
+    # There should only ever be one test server at a time. This may do the
+    # wrong thing if we try and start multiple test servers.
+    if not self.server.test_server_instance:
+      return
+    port = self.server.test_server_instance.host_port
+    logging.info('Handling request to kill a test server on port: %d.', port)
+    self.server.test_server_instance.Stop()
+    # Make sure the status of test server is correct before sending response.
+    if _CheckPortAvailable(port):
+      self._SendResponse(200, 'OK', {}, 'killed')
+      logging.info('Test server on port %d is killed', port)
+    else:
+      self._SendResponse(500, 'Test Server Error.', {}, '')
+      logging.info('Encounter problem during killing a test server.')
+    self.server.test_server_instance = None
+
+  def do_POST(self):
+    parsed_path = urlparse.urlparse(self.path)
+    action = parsed_path.path
+    logging.info('Action for POST method is: %s.', action)
+    if action == '/start':
+      self._StartTestServer()
+    else:
+      self._SendResponse(400, 'Unknown request.', {}, '')
+      logging.info('Encounter unknown request: %s.', action)
+
+  def do_GET(self):
+    parsed_path = urlparse.urlparse(self.path)
+    action = parsed_path.path
+    params = urlparse.parse_qs(parsed_path.query, keep_blank_values=1)
+    logging.info('Action for GET method is: %s.', action)
+    for param in params:
+      logging.info('%s=%s', param, params[param][0])
+    if action == '/kill':
+      self._KillTestServer()
+    elif action == '/ping':
+      # The ping handler is used to check whether the spawner server is ready
+      # to serve the requests. We don't need to test the status of the test
+      # server when handling ping request.
+      self._SendResponse(200, 'OK', {}, 'ready')
+      logging.info('Handled ping request and sent response.')
+    else:
+      self._SendResponse(400, 'Unknown request', {}, '')
+      logging.info('Encounter unknown request: %s.', action)
+
+
+class SpawningServer(object):
+  """The class used to start/stop a http server."""
+
+  def __init__(self, test_server_spawner_port, device, tool):
+    logging.info('Creating new spawner on port: %d.', test_server_spawner_port)
+    self.server = BaseHTTPServer.HTTPServer(('', test_server_spawner_port),
+                                            SpawningServerRequestHandler)
+    self.server.device = device
+    self.server.tool = tool
+    self.server.test_server_instance = None
+    self.server.build_type = constants.GetBuildType()
+
+  def _Listen(self):
+    logging.info('Starting test server spawner')
+    self.server.serve_forever()
+
+  def Start(self):
+    """Starts the test server spawner."""
+    listener_thread = threading.Thread(target=self._Listen)
+    listener_thread.setDaemon(True)
+    listener_thread.start()
+
+  def Stop(self):
+    """Stops the test server spawner.
+
+    Also cleans the server state.
+    """
+    self.CleanupState()
+    self.server.shutdown()
+
+  def CleanupState(self):
+    """Cleans up the spawning server state.
+
+    This should be called if the test server spawner is reused,
+    to avoid sharing the test server instance.
+    """
+    if self.server.test_server_instance:
+      self.server.test_server_instance.Stop()
+      self.server.test_server_instance = None