remote_facade_factory.py revision 8b3c4269e847b8a1bc2f2de9d055b3a807b9bffa 
1# Copyright 2014 The Chromium OS 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
5import httplib
6import logging
7import socket
8import xmlrpclib
9import pprint
10import sys
11
12from autotest_lib.client.common_lib.cros import retry
13from autotest_lib.client.cros import constants
14from autotest_lib.server import autotest
15from autotest_lib.server.cros.multimedia import audio_facade_adapter
16from autotest_lib.server.cros.multimedia import browser_facade_adapter
17from autotest_lib.server.cros.multimedia import display_facade_adapter
18from autotest_lib.server.cros.multimedia import system_facade_adapter
19from autotest_lib.server.cros.multimedia import usb_facade_adapter
20
21
22class _Method:
23    """Class to save the name of the RPC method instead of the real object.
24
25    It keeps the name of the RPC method locally first such that the RPC method
26    can be evalulated to a real object while it is called. Its purpose is to
27    refer to the latest RPC proxy as the original previous-saved RPC proxy may
28    be lost due to reboot.
29
30    The call_method is the method which does refer to the latest RPC proxy.
31    """
32    def __init__(self, call_method, name):
33        self.__call_method = call_method
34        self.__name = name
35
36    def __getattr__(self, name):
37        # Support a nested method.
38        return _Method(self.__call_method, "%s.%s" % (self.__name, name))
39
40    def __call__(self, *args, **dargs):
41        return self.__call_method(self.__name, *args, **dargs)
42
43
44class RemoteFacadeProxy(object):
45    """An abstraction of XML RPC proxy to the DUT multimedia server.
46
47    The traditional XML RPC server proxy is static. It is lost when DUT
48    reboots. This class reconnects the server again when it finds the
49    connection is lost.
50
51    """
52
53    XMLRPC_CONNECT_TIMEOUT = 90
54    XMLRPC_RETRY_TIMEOUT = 180
55    XMLRPC_RETRY_DELAY = 10
56
57    def __init__(self, host):
58        """Construct a RemoteFacadeProxy.
59
60        @param host: Host object representing a remote host.
61        """
62        self._client = host
63        self._xmlrpc_proxy = None
64        self.connect(reconnect=False)
65
66
67    def __getattr__(self, name):
68        """Return a _Method object only, not its real object."""
69        return _Method(self.__call_proxy, name)
70
71
72    def __call_proxy(self, name, *args, **dargs):
73        """Make the call on the latest RPC proxy object.
74
75        This method gets the internal method of the RPC proxy and calls it.
76
77        @param name: Name of the RPC method, a nested method supported.
78        @param args: The rest of arguments.
79        @param dargs: The rest of dict-type arguments.
80        @return: The return value of the RPC method.
81        """
82        try:
83            # TODO(ihf): This logs all traffic from server to client. Make the spew optional.
84            rpc = (
85                '%s(%s, %s)' %
86                (pprint.pformat(name), pprint.pformat(args),
87                 pprint.pformat(dargs)))
88            try:
89                value = getattr(self._xmlrpc_proxy, name)(*args, **dargs)
90                if type(value) is str and value.startswith('Traceback'):
91                    raise Exception('RPC error: %s\n%s' % (name, value))
92                logging.info('RPC %s returns %s.', rpc, pprint.pformat(value))
93                return value
94            except (socket.error,
95                    xmlrpclib.ProtocolError,
96                    httplib.BadStatusLine):
97                # Reconnect the RPC server in case connection lost, e.g. reboot.
98                self.connect(reconnect=True)
99                # Try again.
100                logging.warning('Retrying RPC %s.', rpc)
101                value = getattr(self._xmlrpc_proxy, name)(*args, **dargs)
102                if type(value) is str and value.startswith('Traceback'):
103                    raise Exception('RPC error: %s\n%s' % (name, value))
104                logging.info('RPC %s returns %s.', rpc, pprint.pformat(value))
105                return value
106        except:
107            logging.error(
108                'Failed RPC %s with status [%s].', rpc, sys.exc_info()[0])
109            raise
110
111
112    def connect(self, reconnect):
113        """Connects the XML-RPC proxy on the client.
114
115        @param reconnect: True for reconnection, False for the first-time.
116        """
117        @retry.retry((socket.error,
118                      xmlrpclib.ProtocolError,
119                      httplib.BadStatusLine),
120                      timeout_min=self.XMLRPC_RETRY_TIMEOUT / 60.0,
121                      delay_sec=self.XMLRPC_RETRY_DELAY)
122        def connect_with_retries(reconnect):
123            """Connects the XML-RPC proxy with retries.
124
125            @param reconnect: True for reconnection, False for the first-time.
126            """
127            if reconnect:
128                command = constants.MULTIMEDIA_XMLRPC_SERVER_RESTART_COMMAND
129            else:
130                command = constants.MULTIMEDIA_XMLRPC_SERVER_COMMAND
131
132            self._xmlrpc_proxy = self._client.rpc_server_tracker.xmlrpc_connect(
133                    command,
134                    constants.MULTIMEDIA_XMLRPC_SERVER_PORT,
135                    command_name=(
136                        constants.MULTIMEDIA_XMLRPC_SERVER_CLEANUP_PATTERN
137                    ),
138                    ready_test_name=(
139                        constants.MULTIMEDIA_XMLRPC_SERVER_READY_METHOD),
140                    timeout_seconds=self.XMLRPC_CONNECT_TIMEOUT,
141                    logfile=constants.MULTIMEDIA_XMLRPC_SERVER_LOG_FILE)
142
143        logging.info('Setup the connection to RPC server, with retries...')
144        connect_with_retries(reconnect)
145
146
147    def __del__(self):
148        """Destructor of RemoteFacadeFactory."""
149        self._client.rpc_server_tracker.disconnect(
150                constants.MULTIMEDIA_XMLRPC_SERVER_PORT)
151
152
153class RemoteFacadeFactory(object):
154    """A factory to generate remote multimedia facades.
155
156    The facade objects are remote-wrappers to access the DUT multimedia
157    functionality, like display, video, and audio.
158
159    """
160
161    def __init__(self, host):
162        """Construct a RemoteFacadeFactory.
163
164        @param host: Host object representing a remote host.
165        """
166        self._client = host
167        # Make sure the client library is on the device so that the proxy code
168        # is there when we try to call it.
169        client_at = autotest.Autotest(self._client)
170        client_at.install()
171        self._proxy = RemoteFacadeProxy(self._client)
172
173
174    def ready(self):
175        """Returns the proxy ready status"""
176        return self._proxy.ready()
177
178
179    def create_audio_facade(self):
180        """Creates an audio facade object."""
181        return audio_facade_adapter.AudioFacadeRemoteAdapter(
182                self._client, self._proxy)
183
184
185    def create_display_facade(self):
186        """Creates a display facade object."""
187        return display_facade_adapter.DisplayFacadeRemoteAdapter(
188                self._client, self._proxy)
189
190
191    def create_system_facade(self):
192        """Creates a system facade object."""
193        return system_facade_adapter.SystemFacadeRemoteAdapter(
194                self._client, self._proxy)
195
196
197    def create_usb_facade(self):
198        """"Creates a USB facade object."""
199        return usb_facade_adapter.USBFacadeRemoteAdapter(self._proxy)
200
201
202    def create_browser_facade(self):
203        """"Creates a browser facade object."""
204        return browser_facade_adapter.BrowserFacadeRemoteAdapter(self._proxy)
205