sdk/platform-tools/systrace/catapult/devil/devil/android/ports.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 """Functions that deal with local and device ports."""
   6
   7 import contextlib
   8 import fcntl
   9 import httplib
  10 import logging
  11 import os
  12 import socket
  13 import traceback
  14
  15 logger = logging.getLogger(__name__)
  16
  17 # The net test server is started from port 10201.
  18 _TEST_SERVER_PORT_FIRST = 10201
  19 _TEST_SERVER_PORT_LAST = 30000
  20 # A file to record next valid port of test server.
  21 _TEST_SERVER_PORT_FILE = '/tmp/test_server_port'
  22 _TEST_SERVER_PORT_LOCKFILE = '/tmp/test_server_port.lock'
  23
  24
  25 # The following two methods are used to allocate the port source for various
  26 # types of test servers. Because some net-related tests can be run on shards at
  27 # same time, it's important to have a mechanism to allocate the port
  28 # process-safe. In here, we implement the safe port allocation by leveraging
  29 # flock.
  30 def ResetTestServerPortAllocation():
  31   """Resets the port allocation to start from TEST_SERVER_PORT_FIRST.
  32
  33   Returns:
  34     Returns True if reset successes. Otherwise returns False.
  35   """
  36   try:
  37     with open(_TEST_SERVER_PORT_FILE, 'w') as fp:
  38       fp.write('%d' % _TEST_SERVER_PORT_FIRST)
  39     return True
  40   except Exception:  # pylint: disable=broad-except
  41     logger.exception('Error while resetting port allocation')
  42   return False
  43
  44
  45 def AllocateTestServerPort():
  46   """Allocates a port incrementally.
  47
  48   Returns:
  49     Returns a valid port which should be in between TEST_SERVER_PORT_FIRST and
  50     TEST_SERVER_PORT_LAST. Returning 0 means no more valid port can be used.
  51   """
  52   port = 0
  53   ports_tried = []
  54   try:
  55     fp_lock = open(_TEST_SERVER_PORT_LOCKFILE, 'w')
  56     fcntl.flock(fp_lock, fcntl.LOCK_EX)
  57     # Get current valid port and calculate next valid port.
  58     if not os.path.exists(_TEST_SERVER_PORT_FILE):
  59       ResetTestServerPortAllocation()
  60     with open(_TEST_SERVER_PORT_FILE, 'r+') as fp:
  61       port = int(fp.read())
  62       ports_tried.append(port)
  63       while not IsHostPortAvailable(port):
  64         port += 1
  65         ports_tried.append(port)
  66       if (port > _TEST_SERVER_PORT_LAST or
  67           port < _TEST_SERVER_PORT_FIRST):
  68         port = 0
  69       else:
  70         fp.seek(0, os.SEEK_SET)
  71         fp.write('%d' % (port + 1))
  72   except Exception:  # pylint: disable=broad-except
  73     logger.exception('Error while allocating port')
  74   finally:
  75     if fp_lock:
  76       fcntl.flock(fp_lock, fcntl.LOCK_UN)
  77       fp_lock.close()
  78   if port:
  79     logger.info('Allocate port %d for test server.', port)
  80   else:
  81     logger.error('Could not allocate port for test server. '
  82                  'List of ports tried: %s', str(ports_tried))
  83   return port
  84
  85
  86 def IsHostPortAvailable(host_port):
  87   """Checks whether the specified host port is available.
  88
  89   Args:
  90     host_port: Port on host to check.
  91
  92   Returns:
  93     True if the port on host is available, otherwise returns False.
  94   """
  95   s = socket.socket()
  96   try:
  97     s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
  98     s.bind(('', host_port))
  99     s.close()
 100     return True
 101   except socket.error:
 102     return False
 103
 104
 105 def IsDevicePortUsed(device, device_port, state=''):
 106   """Checks whether the specified device port is used or not.
 107
 108   Args:
 109     device: A DeviceUtils instance.
 110     device_port: Port on device we want to check.
 111     state: String of the specified state. Default is empty string, which
 112            means any state.
 113
 114   Returns:
 115     True if the port on device is already used, otherwise returns False.
 116   """
 117   base_urls = ('127.0.0.1:%d' % device_port, 'localhost:%d' % device_port)
 118   netstat_results = device.RunShellCommand(
 119       ['netstat', '-a'], check_return=True, large_output=True)
 120   for single_connect in netstat_results:
 121     # Column 3 is the local address which we want to check with.
 122     connect_results = single_connect.split()
 123     if connect_results[0] != 'tcp':
 124       continue
 125     if len(connect_results) < 6:
 126       raise Exception('Unexpected format while parsing netstat line: ' +
 127                       single_connect)
 128     is_state_match = connect_results[5] == state if state else True
 129     if connect_results[3] in base_urls and is_state_match:
 130       return True
 131   return False
 132
 133
 134 def IsHttpServerConnectable(host, port, tries=3, command='GET', path='/',
 135                             expected_read='', timeout=2):
 136   """Checks whether the specified http server is ready to serve request or not.
 137
 138   Args:
 139     host: Host name of the HTTP server.
 140     port: Port number of the HTTP server.
 141     tries: How many times we want to test the connection. The default value is
 142            3.
 143     command: The http command we use to connect to HTTP server. The default
 144              command is 'GET'.
 145     path: The path we use when connecting to HTTP server. The default path is
 146           '/'.
 147     expected_read: The content we expect to read from the response. The default
 148                    value is ''.
 149     timeout: Timeout (in seconds) for each http connection. The default is 2s.
 150
 151   Returns:
 152     Tuple of (connect status, client error). connect status is a boolean value
 153     to indicate whether the server is connectable. client_error is the error
 154     message the server returns when connect status is false.
 155   """
 156   assert tries >= 1
 157   for i in xrange(0, tries):
 158     client_error = None
 159     try:
 160       with contextlib.closing(httplib.HTTPConnection(
 161           host, port, timeout=timeout)) as http:
 162         # Output some debug information when we have tried more than 2 times.
 163         http.set_debuglevel(i >= 2)
 164         http.request(command, path)
 165         r = http.getresponse()
 166         content = r.read()
 167         if r.status == 200 and r.reason == 'OK' and content == expected_read:
 168           return (True, '')
 169         client_error = ('Bad response: %s %s version %s\n  ' %
 170                         (r.status, r.reason, r.version) +
 171                         '\n  '.join([': '.join(h) for h in r.getheaders()]))
 172     except (httplib.HTTPException, socket.error) as e:
 173       # Probably too quick connecting: try again.
 174       exception_error_msgs = traceback.format_exception_only(type(e), e)
 175       if exception_error_msgs:
 176         client_error = ''.join(exception_error_msgs)
 177   # Only returns last client_error.
 178   return (False, client_error or 'Timeout')